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33 rd European Congress of Pathology – Abstracts

A Correction to this article was published on 12 November 2021

A Correction to this article was published on 25 October 2021

A Correction to this article was published on 23 September 2021

A Correction to this article was published on 21 September 2021

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OFP-01 | Autopsy Pathology

OFP-01-001

Myocardial pathology in pregnancy - an autopsy study

P. Zare*, P. Vaideeswar

*Seth G.S. Medical College and K.E.M. Hospital, India

Background & objectives: Peripartum cardiomyopathy (PPCM) is an idiopathic left ventricular systolic dysfunction leading to cardiac failure in last trimester of pregnancy or in the postpartum period. Aim is to identify the clinical presentation and pathological features of PPCM among the maternal deaths.

Methods: We conducted a retrospective autopsy study of pathologically diagnosed cases of PPCM in maternal deaths in tertiary centre from 2012 to 2020. Analysed details were demographics, duration and type of symptoms, clinical diagnosis and investigations. The hearts were dissected by the inflow-outflow method. Samples were taken from right and left ventricular myocardia and examined by routine and/or special staining techniques.

Results: Among the 425 autopsies performed, 25 patients (5.8%) were diagnosed as PPCM on clinico-pathological basis. The mean age was 26.9 years. Among these, 5 (20%) patients were clinically diagnosed as PPCM or dilated cardiomyopathy, where an echocardiology showed an ejection fraction <45%, presented with dyspnoea and had associated pregnancy-related disorders like eclampsia and acute fatty liver. In the remaining 20 patients (80%), the diagnosis was made on the assessment of cardiac pathological features. The patients had varied clinical presentation associated with preeclampsia, puerperal sepsis and postpartum haemorrhage. Histologically, 12 hearts (48%) had myocarditis, while 13 (52%) had histological features of dilated cardiomyopathy. Among the latter, 7 hearts had mural thrombi.

Conclusion: Recent research has suggested the important initiating and driving factor for PPCM is the shift in angiogenic balance and development of anti-angiogenic environment. Even with the substantial advancement in understanding the pathogenesis of this relatively uncommon condition, this enigmatic entity significantly causes morbidity and mortality so cautious diagnosis is of paramount importance. This study is an attempt to highlight the pathological features of PPCM cases to aid further understanding of this condition.

OFP-01-002

Minimally invasive tissue sampling findings in 12 patients with COVID-19

N. Rakislova*, M.T. Rodrigo-Calvo, J. Ordi, E. Ortiz, L. Marimon, M. Ferrando

*ISGlobal, Spain

Background & objectives: Complete autopsy is frequently not feasible in COVID-19. Minimally invasive tissue sampling (MITS) may be an alternative. We aimed to compare the MITS performance versus the complete autopsy in COVID-19 deaths and evaluate the safety of the procedure.

Methods: We conducted MITS to 12 adults who tested positive pre-mortem for COVID-19. MITS was performed in a standard well-ventilated autopsy room, and the personnel used only reinforced protective equipment. In nine cases, a complete autopsy was performed after the MITS. A thorough histological evaluation was conducted, and the presence of COVID-19 was evaluated by PCR in a range of samples.

Results: The diagnoses of the MITS matched almost perfectly those of the complete autopsy in COVID-19-associated deaths. In nine patients, COVID-19 was in the chain of events leading to death, being responsible for diffuse alveolar damage and mononuclear T-cell inflammatory response in the lungs. No specific COVID-19 features were identified by MITS nor complete autopsy in any organ. Three deaths were not related to COVID-19. All the personnel involved in the MITS tested repeatedly negative for COVID-19.

Conclusion: MITS is a useful tool to evaluate COVID-19-related deaths in settings where complete autopsy is not feasible. The results of this simplified and safer technique are comparable to those of the complete autopsy.

OFP-01-003

Pandemics of our times: AH1N1 influenza versus COVID-19 – features of fatal cases in Romania

C. Popp*, L. Nichita, M. Neagu, C. Constantin, C. Dumitru, M. Bușcă, M. Cioplea, L. Sticlaru, A. Cioroianu, C. Mogodici, S.A. Zurac

*Colentina University Hospital, Romania

Background & objectives: During the last two decades, we faced two severe pandemics of air-borne infections: 2009-2010 pandemic of AH1N1 influenza (AI) and the present COVID-19 pandemic. Both diseases had a high mortality, but there are significant differences of characteristics between fatal cases.

Methods: We examined records from 97 consecutive fatal cases of AI that underwent post-mortem examination in our department in 2009 and 2010 and from 125 consecutive fatal cases of COVID-19 from our hospital (only 8 of them underwent autopsy). Demographic, clinical and pathological data were compared.

Results: Significant differences (AI versus COVID-19) were found between sex ratio (M:F of 1.7:1 versus 1.1:1), age (medium age of 42.01 versus 69.91). Pregnancy and post-partum period was a risk factor only for AI (9 out 36 women versus none in COVID-19 group). Obesity was frequent in both groups: (20.6% versus 21.6 considering that Romania has an obesity incidence of 9.4%). Some comorbidities were found in both groups (AI versus COVID-19): diabetes (10.3% versus 39.2%), malignancies (6.2 versus 22.4), and cardiovascular diseases (20.6% versus 63.2%). Histologic findings showed differences regarding thrombosis: only 6 out 97 cases of AI and all 7 cases of COVID-19, while DAD was more extensive in AI.

Conclusion: AI fatal cases were younger, healthier persons with very few severe comorbidities. While pregnancy and post-partum period is a risk factor for death in AI, obesity was equally affecting both groups. Knowing these characteristics, we can better tailor prophylaxis and surveillance of population during infectious pandemics, reducing the number of fatal cases.

OFP-01-004

Multiple organ pathology in SARS-COV-2: reports of 232 autopsy cases

E. Kogan*, Y. Berezovskij, T. Demura, S. Demura

*Sechenov University, Russia

Background & objectives: Pathological anatomy of SARS Cov-2 infection is still being investigated.

Methods: We report data of 232 autopsy of patients died from the COVID-19 infection confirmed by PCR during life and/or by examining paraffin blocks of lung tissue. Majority of patients were more than 65 years and had comorbid conditions (diabetes mellitus, obesity, ischemic heart disease and etc). Using macro- and microscopic studies, specific features of pathological processes in organs were identified.

Results: Lungs - diffuse alveolar damage, disseminated coagulopathy; lymphocytic alveolitis, viral-bacterial pneumonia, interstitial fibrosis and disregeneration changes of the lung epithelium; heart – lymphocytic endomyocarditis and coronoratis with thrombosis, ischemic damage of cardiomyocytes; brain – degeneration of neurons, vesculitis, edema and encephalitis in 3 cases; kidney – collaptoid glomerulopathy and tubulonecrosis; liver – steatohepatitis, foci of necrosis; endocrine system – adrenalities, lymphocytic thyroiditis, insulinitis; skin and skeletal muscle tissue – vasculitis. Coagulopathy associated to SARS Cov-2 was found in all organs.

Conclusion: The obtained data reveal the mechanisms of organs damage and individual aspects of COVID-19 pathogenesis. The thanatogenesis of the disease and the main causes of death are discussed, including acute cardiopulmonary failure, acute renal failure, pulmonary thromboembolism, shock involving multiple organ failure and sepsis.

The critical importance of autopsy is emphasized, which provides valuable information on the morphological substrate for this infection closely associated with possible clinical manifestations.

OFP-02 | Breast Pathology

OFP-02-001

A multi-feature AI-based solution for cancer diagnosis in breast biopsies: a prospective blinded multi-site clinical study

A. Vincent-Salomon*, G. Bataillon, A. Nudelman, J. Sandbank, A. Albrecht Shach, L. Thibault, L. Bien, R. Mikulinsky, I. Krasnitsky, R. Heled, C. Linhart, M. Vecsler, D. Laifenfeld

*Department of Pathology, Institut Curie, Paris, France

Background & objectives: This study aimed to clinically validate the performance of a multi-feature AI-based solution on detection of invasive and in situ ductal carcinoma or atypical ductal hyperplasia against rigorous ground truth (GT) established by multiple blinded expert pathologists in breast biopsies.

Methods: Performance of the AI solution was prospectively tested on breast biopsies from 2 medical institutions in different geographies. AI results were compared against the ground truth (GT) established by consensus of two subspecialist breast pathologists. The study endpoints were detection of invasive carcinoma (IDC, ILC) and DCIS/ADH. ADH and DCIS low grade were pooled together because of similar clinical management.

Results: Six pathologists participated in the study and reported on 417 breast biopsies (872 H&E slides), including 135 invasive, 137 DCIS/ADH, and 145 benign diagnoses. 10 (2.4%) cases had discrepancies on invasive diagnosis, and 15 (3.6%) cases had discrepancies on DCIS/ADH diagnosis between the two specialist pathologists necessitating a third assessment by a specialist to establish GT. 4 of these cases also necessitated a committee decision since there was no majority even after 3 reviews. The AI solution demonstrated high performance when compared with the GT with AUC as high as 0.994 for the detection of invasive carcinoma, with specificity and sensitivity up to 95.4% and 98.4% respectively.

Conclusion: This blinded multi-site study reports the successful clinical validation of a multi-feature AI-based solution in detecting and automatically imparting clinically relevant diagnostic parameters regarding invasive and in situ breast carcinoma, offering an important tool for computer-aided diagnosis in routine pathology practice.

OFP-02-002

Digital pathologist training program on the evaluation of PD-L1 expression by VentanaPD-L1 (SP142) in triple negative breast cancer

M. Viegas*, D.F. Schmitt, H. Pereira, S. Pinto Torres, A.S. Rebelo, D. Matos, A. Dias

*Roche Diagnostics, Portugal

Background & objectives: Unresectable locally advanced or metastatic triple negative breast cancer may presents expression of PD-L1≥1 in the immune cells. Pathologist training is critical for right interpretation of PD-L1 expression. We report the results of the training in Portugal for the Ventana PD-L1 test (SP142).

Methods: In each training there were 10 to 12 pathologists-during 1 day-using a novel digital training platform–Pathomation. The Sessions consisted of 1) consensual analysis of 10 known cases 2) self study - 4 known cases followed by trainer-led group discussion 3) pre test – 8 unknown cases followed by trainer-led group discussion 4) proficiency test – 28 cases followed by discordant case review with the trainer.

Results: Between March 7, 2019 and February 19, 2020, 6 training sessions were held including 64 pathologists from 30 institutions nationwide. 100% of the pathologists met the approval criteria of the Roche International Pathologist Training Program (score ≥85% on the Proficiency Test). The overall percent agreement, positive percent agreement and negative percent agreement at the Proficiency test was 97%, 97.5% and 96.5%, respectively.

Conclusion: The assessment of PD-L1 expression on IC is a new concept for pathologists. This training program showed excellent pathologist’s concordance scores, establishing the feasibility and effectiveness of such trainings in triple negative breast cancer.

OFP-02-003

Correlation of tumour subtype with long-term outcome in small breast carcinomas: a Swedish population-based retrospective cohort study

G. Rask*, A. Nazemroaya, M. Jansson, C. Wadsten, G. Nilsson, C. Blomqvist, L. Holmberg, F. Wärnberg, M. Sund

*Department of Medical Biosciences/Pathology and Department of Surgery and Perioperative sciences/ Surgery Umeå University, Sweden

Background & objectives: Breast cancer (BC) is increasingly detected at stage 1, hence treatment decisions are more often influenced by tumour biology than stage. Our study aims to explore if there is any association between tumour subtype and outcome in these small tumours.

Methods: We classified samples from 445 women with unifocal, node negative BC <15 mm, treated 1986-2004 into surrogate molecular subtypes (Luminal A-like, Luminal B-like, Her2-positive, and triple negative breast cancer (TNBC)) by immunohistochemistry and in situ hybridization. Information on treatment, overall survival, breast cancer-specific survival (BCSS) and incidence of locoregional and distant metastasis were gathered from medical records.

Results: Median follow-up for women alive was 19.8 years and no patient was lost to follow up. Tumour subtype was not associated with overall survival. Luminal B-like and TNBC were associated with a two- and threefold higher incidence of distant metastasis at 20 years, in comparison to Luminal A-like BC, respectively. Women with TNBC and Luminal B-like tumours had worse breast cancer specific survival but this was not statistically significant. Her2-positive subtype had no certain association with any outcome despite the fact that no woman received Her2-targeted therapy.

Conclusion: TNBC or Luminal B-like tumours behave more aggressively than Luminal A-like tumours, even at stage 1. Prospective studies are needed to clarify if this means these women benefit from adjuvant chemotherapy. Women with Her2+/ER+-tumours do not seem to have an increased risk of distant metastasis or death, absent targeted treatment.

Funding: Lions Cancer Research Foundation, Swedish Breast Cancer Association, Percy Falk Foundation, Northern County Councils Regional Federation (grant: VISARENORR750491 and VISARENORR931408), ALF funding from Region Västerbotten.

OFP-02-004

Cystic neutrophilic granulomatous mastitis: a retrospective reassessment of granulomatous mastitis patients

Z.C. Olgun*, A. Aydin, H. Baysal, B. Baysal, G. Kir

*Medeniyet University, Prof. Dr. Suleyman Yalcin City Hospital, Department of Pathology, Turkey

Background & objectives: Cystic neutrophilic granulomatous mastitis (CNGM) is an increasingly recognised subtype of granulomatous mastitis often associated with Corynebacterium species. CNGM usually occurs in reproductive age women and typically characterised with pain, discharge, mass formation, nipple retraction and sinuses at unilateral breast.

Methods: A retrospective search for breast specimens with granulomatous inflammation from 2010 to 2020 was performed. Through this ten year period there were 108 female patients diagnosed with granulomatous mastitis whose slides were available for review. Haematoxylin and eosin slides were reviewed for typical histological features of CNGM. Slides which were suspicious of CNGM were stained with gram for microorganisms.

Results: Thirty-five (32,4%) cases were identified as CNGM with characteristic suppurative lipogranulomas that are composed of central lipid vacuoles rimmed by neutrophils and an outer cuff of epithelioid histiocytes. Mean age was 34,6 (23-51 years), all patients were at a reproductive age, except one. Gram stains revealed organisms in 14 (48,2%) of 29 cases. The patients had various management approaches, including surgery, steroids and antimicrobials. Nine (25.7%) patients received antibiotics, six (17.1%) patients received local and two (5.7%) patients received systemic steroids, nine (25.7%) patients underwent segmental mastectomy. Eight (22,9%) patients had recurrent disease.

Conclusion: Although there is no consensus in the treatment of CNGM, Prolonged antibiotic therapy with lipophilic antibiotics as Doxycycline, Clarithromycin, Rifampicin and Co-trimaxazole are used for mostly isolated Corynebacterium species. Collaborative communication between specialists to accurately diagnose and manage these patients is essential to decreasing potential morbidity.

OFP-02-005

Response and outcomes of invasive mucinous carcinoma of the breast after neoadjuvant chemotherapy

G. Kir, Z.C. Olgun*, H. Seneldir, S. Koca, I. Tosun, O. Alimoglu

*Medeniyet University, Prof. Dr. Suleyman Yalcin City Hospital, Department of Pathology, Turkey

Background & objectives: Mucinous breast carcinoma (MBC) accounts for approximately 2% of all breast cancers. There is limited data in the literature regarding the response and outcomes of MBC after neoadjuvant chemotherapy (NAC).

Methods: Eight patients with localized non-metastatic MBC who had been treated with NAC between 2010-2019 were identified. Paraffin blocks were available for all of the patients, as were H&E and immunohistochemistry slides of both their core biopsies and mastectomy or breast-conserving surgery specimens.

Results: Seven patients had a consistent pathologic response score at both the primary tumour site and the axillary lymph nodes after the NAC. Four patients had no pathologic response at both the primary tumour site and the axillary lymph nodes. Three patients had a partial pathologic response at both the primary tumour site and the axillary lymph nodes. One patient had a partial pathologic response at the primary tumour site but she did not have axillary lymph node involvement. Two patients, who had no pathologic response, had recurrent disease after 26 and 31 months of follow-up after surgery and they both died after 65 and 66 months of follow up, respectively.

Conclusion: In our series, none of the patients achieved a complete pathological response of the primary tumour and/or the axillary LNs. We observed that the pathological responses of the primary tumour and axillary LNs of the patients were correlated.

OFP-02-006

Lineage-specific methylation profiles in phyllodes tumours of the breast and their mimics

J. Hench, T. Vlajnic, S.D. Soysal, E. Obermann, S. Frank, S. Muenst*

*Institute of Pathology, University Hospital Basel, Switzerland

Background & objectives: Phyllodes tumour (PT) poses a diagnostic challenge, as there are no generally accepted criteria to distinguish PT from fibroadenoma (FA) or to separate between benign, borderline, and malignant PT. DNA methylation analysis represents an important tool to objectively classify tumours.

Methods: We used fresh/frozen as well as formalin-fixed, paraffin-embedded patient samples to determine DNA methylation patterns of 41 PT (22 initially diagnosed as benign, 8 borderline, 10 malignant, 1 not specified) on a standard microarray. 11 FA , 6 primary breast sarcomas and 1 metaplastic carcinoma were included as reference. Identified CNV aberrations were confirmed with fluorescence in situ hybridization (FISH).

Results: In analogy to other tumour entities, PT and FA show distinct DNA methylation profiles reflecting a breast-specific signature as well as tumour-derived patterns. PT/FA form a molecular subgroup distinct from normal breast tissue and invasive breast cancer. Whereas the histologically malignant PT are enriched for complex copy number alterations, the benign PT and FA feature less prominent to no copy number variants and their methylation signature shows a higher similarity to physiological breast tissue.

Conclusion: DNA methylation profiling allows distinction of two PT categories (benign/malignant). Of note, elimination of the diagnostically problematic category of borderline PT allows optimized prognostic patient stratification. The significant molecular overlap between benign PT and FA prompts for omission of their diagnostic distinction. Moreover, methylation and subsequent FISH analysis shows recurrent genomic aberrations limited to the neoplastic stromal cells, such as 1q gains (including the MDM4 locus), as well as CDKN2A deletions and EGFR amplifications, which may be exploited therapeutically.

Funding: Domarena Foundation Parrotia Foundation

OFP-02-007

Repeatable study of tumour infiltrating lymphocytes in breast cancer after neoadjuvant therapy based on artificial intelligence

M. Zhao, Y. Liu*

*The Fourth Hospital of Hebei Medical University, China

Background & objectives: Visual quantitative assessment of tumour-infiltrating lymphocyte(TILs) in breast cancer after neoadjuvant therapy lacks accuracy and repeatability. This study compared the difference and repeatability of visual assessment (VA) and Artificial intelligence(AI) assisted interpretation of TILs of breast cancer after neoadjuvant therapy under microscope.

Methods: This study included 50 patients with invasive breast cancer in the fourth hospital of Hebei Medical University from 2014 to 2015 and underwent surgical resection after neoadjuvant therapy. Nine pathologists of different levels used evaluate TILs of breast cancer after neoadjuvant therapy by VA and AI-assisted. In this study, SPSS 26.0 and GraphPad Prism 8.0.1 were used for statistical analysis.

Results: Nine pathologists in the VA group and the AI-assisted group found that the TILs of 50 cases of breast cancer after neoadjuvant therapy. The Friedman M test further showed that the interpretation results of the 9 pathologists in the VA group were significantly different (P<0.001), the interpretation results of the 9 pathologists in the AI-assisted group were no significant difference (P=0.416). There was no significant difference only between senior pathologists in the VA group in the TILs interpretation. The ICCs of TILs interpretation for breast cancer after neoadjuvant therapy between all pathologists in AI-assisted group and the gold standard were higher than 0.9.

Conclusion: AI significantly improves the consistency and repeatability of the interpretation results of TILs by pathologists. It can be seen that AI-assisted pathologists is a good way to improve the consistency and repeatability of the TILs interpretation results of breast cancer.

OFP-02-008

A nomogram for predicting the subgroups of ER low positive breast cancer based on clinicopathological characteristics

S. Niu, Y. Liu*

*The Fourth Hospital of Hebei Medical University, China

Background & objectives: The purpose is to establish a nomogram to predict the expression status of ER based on clinicopathological characteristics, and to identify patients with ER low positive whose clinicopathological characteristics are similar to ER-negative patients.

Methods: 450 invasive breast cancer patients who had surgical treatment in the Fourth Hospital of Hebei Medical University in 2012. ER-negative groups and ER-positive groups of patients were randomly divided into training cohort and verification cohort at a ratio of 7:3. The effectiveness of the nomogram is evaluated by calculating the area under the ROC curve (AUC).

Results: Tumours with obvious nuclear polymorphism, mitosis>20/10 HPF, tumour infiltrating lymphocytes>40%, and necrosis are often ER-negative. The AUC of the nomogram in the training cohort and validation cohort were 0.804 (95% CI 0.750-0.858) and 0.828 (95% CI 0.752-0.903), respectively. By calculating the Yorden index, the best cut-off value for predicting ER expression status is 0.59. The nomogram was used to predict subgroups of patients with ER low positive breast cancer. 164 (63.08%) patients had negative predicted results, and 96 (36.92%) patients had positive predicted results. Among patients with ER low positive, those with negative predicted results have lower expression of ESR1 mRNA, cannot benefit from endocrine therapy and have a poor prognosis.

Conclusion: Based on clinicopathological characteristics, we have developed and verified a nomogram that predicts the expression status of ER in patients with invasive breast cancer. It can be used to identify patients with ER low positive whose clinicopathological characteristics are similar to ER-negative patients and will help guide individualized and precise treatment of ER low positive breast cancer patients.

OFP-02-010

Molecular subtyping of invasive breast cancer using PAM50-based multigene expression testing - comparison with surrogate subtyping by immunohistochemistry and grading and influence on oncologist’s decision on systemic therapy in a real world setting

R. Erber*, M.A.a. Fulvia Ferrazzi, M.P. Lux, D.U.a. Enrico Pelz, A.B.R.F.W.a. Kurt W. Schmid, M.V.a. Christoph Thomssen, D.M.a. Thomas Kirchner, M.W.P.A.F.a. Matthias W. Beckmann, P.S.a. Albrecht Stenzinger, K.S.a. Karl Sotlar, O.H.a. Rainer Kimmig, R.W.a. Nadia Harbeck, R.S.a. Arndt Hartmann

*Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), CCC Erlangen-EMN, Germany

Background & objectives: In breast cancer (BC), therapy decision depends on prognostic and predictive biomarkers including surrogate subtyping by immunohistochemistry (IHC)& grading. In intermediate risk hormone receptor (HR) positive, HER2 negative BC, decision for adjuvant chemotherapy can be supported by multigene expression tests.

Methods: 142 BCs with intermediate clinico-pathological risk were investigated using Prosigna® testing in a prospective multicenter study. Prosigna® molecular subtyping was compared with local and two central (C1 and C6) surrogate subtypes [each IHC (HR, HER2, Ki-67) subtyping and von Minckwitz (IHC+grading) subtyping] utilizing inter-rater reliability (IRR) analysis. Moreover, impact of Prosigna® test results on treatment decision on chemotherapy was studied.

Results: For 119 cases, Prosigna® and surrogate subtyping were available. According to local IHC, 35.4% were Luminal A-like, 64.6% Luminal B-like (local von Minckwitz subtype: 31.9% Luminal A-like/68.1% Luminal B-like). In contrast to local and C1, C6 surrogate subtyping assigned >66.7% of cases to Luminal A-like. Best agreement occurred between Prosigna® (53.8% Luminal A/44.5% Luminal B) and C1 von Minckwitz subtyping (Cohen’s kappa= 0.455). Chemotherapy and endocrine therapy were recommended to 44.2% and 88.6% of Prosigna® Luminal A and Luminal B cases, respectively. For local Luminal A-like cases, chemotherapy and endocrine therapy were recommended if Prosigna® testing classified them as Luminal A with high/intermediate risk or upgraded to Luminal B subtype.

Conclusion: IRR between Prosigna® subtypes and surrogate subtyping was fair to moderate depending on surrogate subtyping method and center. Cases of high Prosigna® risk group were mostly of Prosigna® Luminal B subtype. For Luminal A-like subtypes of breast cancer assessed locally using IHC/von Minckwitz subtyping, adjuvant chemotherapy and endocrine therapy were recommended if multigene expression analysis using Prosigna® assay classified those cases as Prosigna® Luminal A at high/intermediate risk or upgraded to Prosigna® Luminal B breast cancer.

OFP-02-011

Prognostic factors of luminal A and luminal B intrinsic breast cancer subtypes of Croatian patients: a 5-year experience from Osijek

R. Gudelj*, J. Rajc, M. Bakula, R. Alaghehbandan

*Department of Pathology and Forensic Medicine, Osijek University Hospital and Faculty of Medicine, University of Osijek, Croatia

Background & objectives: Prognosis and treatment of breast cancers are associated with clinico-pathologic and biological characteristics of the tumour. The aim of this study was to assess the frequency and prognostic parameters of luminal breast cancers among Croatian breast cancer population.

Methods: A large retrospective cross-sectional study including 1248 cases of primary breast cancer treated at Osijek University Hospital was conducted during 2016–2020. The clinico-pathologic and immunohistochemical (IHC) and dual in situ hybridization (DISH) data were extracted from pathology reports to study the luminal subtypes A and B. The cross-tabulated statistics of the observed characteristics were performed between the two subtypes.

Results: Luminal cancers comprised 89% (1006/1130) of the total number of cases. Of 1006 cases of luminal cancers, 717 cases (71.3%) were luminal B, while 289 (28.7%) were luminal A. Age profile of Luminal A and B cancers were similar (62.8 vs 62.7 years). Luminal B cancers were associated with higher grade (22.9% grade III in luminal B compared to 6.6% in luminal A), micropapillary and metaplastic histology, and high frequency of nodal metastasis (39.8% in luminal B compared to 23.3% in luminal A).

Conclusion: Luminal B is the most frequent subtype of breast cancer in Croatian patients. They were associated with adverse clinico-histologic parameters such as higher grade and nodal metastasis. Our findings suggest that, despite lack of molecular studies in routine practice, IHC/ISH-based typing are sufficient for prognostic and therapeutic stratifications in breast cancers in Croatia.

OFP-02-012

Immunohistochemical markers in breast cancer brain metastases: the role of the cancer stem cell marker CD44 in prognosis

J. Gama*, R. Oliveira Caetano, J. Gama, P. Figueiredo, O. Rebelo, M.A. Cipriano

*Pathology Department, Hospitais da Universidade de Coimbra, Centro Hospitalar e Universitário Coimbra, Portugal

Background & objectives: Up to 30% of women with breast cancer develop brain metastases (BCBM), and the overall prognosis remains poor.

Different markers are on trial for guiding treatment and provide prognostic information.

Methods: A retrospective transversal study was completed using archival biological material from 114 patients with BCBM, diagnosed between 2000 and 2016 at the Coimbra University Hospital. Expression of CD44, CD133, ALDH1, PD-L1, Her-2, ER, PR, CA9 marks were assessed by immunohistochemistry. Clinical and pathological data was retrieved from the hospital database. The local ethical committee (CHUC-136-20) approved this study.

Results: One hundred and one (89%) metastases were located in the brain parenchyma and 13 (11%) in the bone. The most common site was the cerebellum (34.7%). The median age of presentation was 56 years (32-80 years). After a median follow-up of 10 months (0-225months) the overall survival (OS) was of 10±1.3months. The overexpression of CD44 was associated with a worse OS (7±2.2vs 12±1.8months, p = 0.047), on univariate analysis; however multivariate analysis did not confirm this finding (HR 1,543, 95%CI 0.99-2.4, p=0.055). The remaining markers did not exhibit statistical correlation.

Conclusion: BCBM have a very poor outcome. Cancer stem cell markers, such as CD44, may have prognostic impact on survival in patients BCBM. The conjugation with other markers may help in patients’ stratification and therapy.

OFP-02-013

Tumour-associated macrophages characterisation in invasive breast carcinoma

J. Filipe*, D. Pereira, A. Pinto, S. André

*Serviço de Anatomia Patológica, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisboa, Portugal

Background & objectives: Tumour-associated macrophages (TAM) may have a significant role in carcinogenesis and could be a potential therapeutic target in breast carcinoma (BC). We evaluated the clinicopathological features and correlated them with TAM M1(pro-inflammatory) and M2(immunosuppressive) in molecular subgroups of BC.

Methods: We evaluated 60 untreated BCs; 20 Triple-negative (TN), 20 HER2-enriched (HER2+) and 20 Luminal (ER+). Medical records and histological slides were reviewed. Immunohistochemistry for CD68, pan-macrophage; CD163, CD206, M2 and CD80, M1, was performed. Expression was determined by counting the absolute number of intra-tumoral macrophages in ten high-power-field “hot-spots”. Fisher’s exact test was used for groups comparison.

Results: Patients´ median age was 62,7 years. The median follow-up was 75,65 months (9-250). TN tumours presented with higher stages than ER+ tumours (p=0.026), were frequently bilateral (30%) and BRCA1/2 mutated (30%). TN carcinomas were larger than ER+/HER2+ carcinomas (p=0.008; p=0.041) and more necrotic than ER+ carcinomas (p<0.001). Ki67 was not significantly different among TN/HER2+ tumours but it was higher than ER+ tumours (p<0.001). The number of CD68/CD163 positive cases was higher in TN than ER+ tumours (p=0.008). No statistical difference was found between TN and HER2+ groups. CD80 and CD206 TAM were rare and neither relevant nor different among the 3 groups.

Conclusion: CD163 is more frequent in TN tumours, confirming the relationship between M2 macrophages and tumour aggressiveness in BC. CD163 allows a better estimation of M2 macrophages than CD206. CD80 was not useful in the evaluation of BC TAM.

OFP-02-014

B3 lesions diagnosed on core needle biopsy and diagnostic upgrade at excision: a single institution experience from 2002 to 2018

N. Espejo-Herrera*, E. Guerra, E. Quirós, A. De Carvalho, A. Petit, J. Azcárate, E. Dorca, M.E. Fernández Montoli, M. Vicente Quilez, X. Matias-Guiu, M.T. Soler-Monsó

*Pathology Department, Bellvitge Universitary Hospital, IDIBELL, Spain

Background & objectives: On core needle biopsies (CNB), B3 diagnostic category involves a spectrum of lesions with uncertain malignant potential. We aim to describe B3 lesions, diagnosed on CNB between 2002- 2018, and the final diagnosis on vacuum-assisted biopsy (VAB) and/or tumourectomy (TM).

Methods: We collected information on CNB, VAB and TM of patients diagnosed with: in-situ lobular carcinoma/atypical lobular hyperplasia (LCIS/ALH), radial scar (RS), papillary lesion with/without atypia (PAP), flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH), and fibroepithelial lesion with stromal hypercellularity (FELSH). We contrasted diagnoses of CNB and excision, comparing the percentage of intraductal (IDC) and invasive carcinoma (INVC) by B3 groups.

Results: We identified 410 patients (mean age 48,4 years) diagnosed with LCIS/ALH: 30(7,3%); RS: 63(15,4%); PAP: 66(16,1%); FEA: 60(14,6%); ADH: 74(18,1%), and FELSH: 117(28,5%). 382 (85,9%) showed pure B3 lesions, and 58 (14,1%) combined. Among the 305 (74,4%) patients with excision data: 53 (12,9%) underwent to VAB-only, 238 (58,1%) TT, and 14 (3,1%) VAB+TT. None of the patients treated by VAB-only showed carcinoma. On excision (VAB/TT), diagnoses included: 57 (18,7%) benign lesions (B2), 184 (60,3%) B3 lesions, and 64 (20,9%) carcinoma: 30 (9,8%) INVC, and 34 (11,2%) IDC. Patients with LCIS/ALH showed the highest percentage of INVC (24%) at excision, and those with ADH showed the highest percentage of IDC (33,3%).

Conclusion: In our series, the most frequent B3 diagnoses on CNB were fibroepithelial lesions, and atypical ductal hyperplasia. Most of the lesions identified were pure. Overall, the percentage of upgrade, including invasive and intraductal carcinoma, among our patients with B3 diagnosis was 20,9%, being higher among those with LCIS/ALH and ADH.

OFP-02-015

The impact of COVID-19 on the practice of breast pathologists; a survey of the United Kingdom Breast Pathologists

M. Elghobashy*, L. Wahab, A. Gunavardhan, E. O'Sullivan, E. Provenzano, R. Deb, S. Pritchard, S. Di Palma, I. Ellis, C. Boyd, S. Pinder, A.M. Shaaban

*University of Birmingham, United Kingdom

Background & objectives: There is little information on the impact of COVID-19 on breast pathologists. This survey assesses the effect of the COVID-19 pandemic on UK and Ireland-based breast pathologists in order to optimise working environments and ensure preparedness for potential future pandemics.

Methods: A 35-question survey on working practices during the COVID 19 first wave including redeployment, professional development, training, health and safety & wellbeing was distributed to consultant breast pathologists on the National Coordinating Committee for Breast Pathology and the Association of Breast Pathology databases, and responses collected anonymously.

Results: There were 135 responses from breast pathologists based in the UK and Ireland. Most participants (75.6%) stated that their workload had decreased, and their productivity dropped. 86/135 were given the option of working from home and 36% of those who did reported improved efficiency. Multidisciplinary team meetings (MDTMs) largely moved to virtual platforms (77.8%) with fewer members present (41.5%). Online education including webinars and courses were popular and utilised by 92.6%. 16.3% of pathologists reported shortages of masks, visors or gowns as the commonest health and safety concern. 33.3% felt that COVID had a significant negative impact on their physical and mental health. 10.4% were redeployed/retrained.

Conclusion: Going forward, most respondents were keen to adopt flexible working hours, virtual MDTMs, remote working and digital pathology. 57% felt their pathology departments were not adequately prepared for a potential surge in activities due to patient treatment backlogs.

The COVID-19 pandemic significantly impacted on UK breast pathologists and their practice. It is important to apply flexible working patterns and environments that improve productivity and mental health. The changes suggested should be considered for long-term shaping of breast pathology services.

OFP-02-016

Leptomeningeal metastasis of breast carcinoma

E. Dvindenko*, D. Gracez, D. Pereira, S. André

*Instituto Português de Oncologia de Lisboa Francisco Gentil, Portugal

Background & objectives: Leptomeningeal carcinomatosis (LMC) is an uncommon complication of breast carcinoma (BC) associated with poor outcome. We evaluated the clinicopathological features of BC associated with LMC and correlated them with patient survival.

Methods: We performed a retrospective study of patients with LMC from BC diagnosed in cerebrospinal fluid (CSF) from 2000 to 2019 with available histology of primary BC. Clinical data (age, genetic susceptibility, neoadjuvant therapy, metastasis, and follow-up) was accessed from clinical records. CSF slides were reviewed as well as slides from primary BC and other distant metastasis.

Results: Thirty-one female patients with mean age at diagnosis of 51 years (29-81) were included. BRCA1/2 mutations were confirmed in 25% of the patients. Twelve patients had neoadjuvant chemotherapy. Besides LMC, fifteen patients had M1 disease, mostly lung (33.3%). Mean interval between BC diagnosis and LMC (MID) was 56 months (4-161). The median overall survival after LMC (OSLMC) was 3 months (0–13); six months OSLMC was 19.3%. Most tumours were invasive carcinoma of no special type (87.1%), 55.5% grade 3. The proportion of Luminal, HER2+ and TN was 74.2%, 12.9% and 16.1%, the respective MID was 60.8, 31.8 and 34.4 months and the OSLMC was 3.6, 1 and 1.2 months.

Conclusion: The percentage of patients with confirmed BRCA1/2 mutations is high in this series. As described in literature, prognosis of patients with LMC is poor, as less than 20% of the patients were alive 6 months after positive CSF. Luminal subtype represented the majority of cases, had the longest interval between BC diagnosis and LMC and the longest survival after positive CSF.

OFP-02-018

In situ-like morphology in invasive ductal carcinoma: association with HER2 gene aberrations and neuroendocrine differentiation

M. Bugdayci Uner*, S. Yıldırım, K. Kösemehmetoğlu

*Department of Pathology, Hacettepe University Faculty of Medicine, Turkey

Background & objectives: Invasive ductal carcinoma, NOS may exhibit a unique ductal carcinoma in-situ-like morphology characterized by lack of myoepithelial layer. Herein we described clinicopathological and immunohistochemical features, as well as hormonal and HER2 status of these tumours.

Methods: Slides of tissue microarrays constructed using 3-mm cores of 26 tumours of 15 female patients were immune-stained for SMA, synaptophysin, and c-erbB2 and subjected to dual HER-2 Gene amplification FISH Probe Kit (Health Care). All slides were scored by two pathologists and also scanned and reviewed via Olympus VS120 automated slide scanner.

Results: The mean age was 51,1(25-76). Mean tumour size was 3,2(0,1-14) cm. Fifteen tumours were grade 3; 9 were grade 2; 2 were grade 1. Seven (58%) cases showed synaptophysin expression, one of which diffuse and strong, while 6 cases had focal synaptophysin expression. All but 3 cases(2 c-erbB2+ and 1 triple-negative) were ER/PR+. Two cases(%29) revealed HER2 overexpression (Her2/Cep 17 ratio >4, group 5), while 5 cases fell into group 4 (Her2/Cep 17 ratio <2, HER2>4 and <6), and the rest were non-amplified (group 5). Nine(64%) tumours, 4 of which expressed synaptophysin, showed polyploidy in a range of 3 to 6 CEP17 copy numbers. Seven(47%) cases showed lymph node metastasis.

Conclusion: Given the fact that neuroendocrine marker expression in breast carcinoma is around 10-30%, synaptophysin expression seems to be slightly overrepresented in this group of tumours. Besides, tumours with HER2 polyploidy revealed higher neuroendocrine differentiation (44%) than the euploid ones. There are some overlapping morphological and immunophenotypical features with invasive solid papillary carcinoma. In our study group with this particular morphological appearance, synaptophysin expression and chromosome 17 polyploidy seem to be a unique-promising finding for further research.

OFP-02-019

Malignant breast papillary neoplasm: a clinico-pathological study of 27 cases

A. Bchir*, S. Chaieb, z. Nfikha, Y. Fejji, T. Tlili, N. Abdessayed, T. Zahmoul, H. Hamchi, B. Sriha, M. Mokni

*Department of Pathology, Farhat Hached Hospital, Tunisia

Background & objectives: Malignant breast papillary neoplasm is a rare type of invasive breast carcinoma. It is characterized by predominant papillary architecture.

The aim of our study was to discuss the clinicopathological features of malignant breast papillary neoplasms.

Methods: In a retrospective study, we report 27 cases of malignant breast papillary neoplasm between 2001 and 2020 obtained from files of Pathology Department of Farhat Hached University Hospital (Sousse, Tunisia).

Results: The patients mean age was 57.35 years. The mean size of tumours was 3.89 cm (ranged between 2.2 and 14 cm). There were 15 cases of invasive papillary carcinoma, 8 cases of encapsulated papillary carcinoma (including 3 with adjacent invasive carcinoma of no special type), 3 cases of solid papillary carcinoma and one papilloma with ductal carcinoma in situ.

Immunostaining with myoepithelial markers, including Ck5/6 and p63 demonstrated the absence of myoepithelial cells both in the papillary fronds and at the periphery of the lesion in encapsulated papillary carcinoma.

Hormonal receptors were positive in 7 cases of invasive papillary carcinoma and 6 cases of encapsulated papillary carcinoma.

Conclusion: The diagnostic of papillary malignant tumours is challenging due to their broad spectrum of clinical, imaging, and histologic characteristics. Their prognosis is better than the invasive carcinoma of no specific type, but their evaluation remains a problematic. Although many of them can be categorized based on H&E-stained sections alone, others require immunostaining. Further studies are needed to elucidate the pathogenesis of these lesions and the potential tools to stratify them.

OFP-02-020

Upgrade rate and risk factors associated with malignancy in breast papillary lesions diagnosed on core biopsy in Greater Vancouver, Canada: a preliminary analysis

S. Koonmee, L. Ali, O. Ondic, K. Pivovarcikova, C. Aphivatanasiri, P. Ungarreevittaya, R. Bhan, J. Rogola, R. Alaghehbandan*

*Department of Pathology and Laboratory Medicine, University of British Columbia, Royal Columbian Hospital, Canada

Background & objectives: Papillary lesions of the breast are a heterogeneous group. The histologic distinction between papillary breast lesions remains challenging. The aim of this study was to determine the rate of malignancy in excised papillary lesions and associated factors in Vancouver, Canada.

Methods: This is a retrospective study of all breast papillary lesions diagnosed on core biopsy between 2017 and 2019 in Fraser Health in Greater Vancouver area, with a 1.8 million population. Cases were categorized into benign, atypical, and malignant. Patient demographics, histopathologic, and radiologic findings were analysed.

Results: This is a preliminary analysis of 57 cases of papillary lesions, including 29 (50.9%) benign, 26 (45.6%) atypical, and 2 (3.5%) ductal carcinoma in situ (DCIS). Mean age was 59.3 years. The age profile of those with benign pathology was significantly younger (53.3 years) than those with malignant (63.5 years) (p=002). The upgrade rate in benign lesions to atypia/malignancy was 17.2% (5/29). Atypia on core needle biopsy was significantly associated with a final malignancy diagnosis (p<0.001). Upgrade rate to invasive carcinoma was found in 4/28 (14.3%) lesions with atypia. Final resection diagnosis with atypia/malignancy was significantly associated with lesions >10 mm and patients older than 55 years (p<0.01).

Conclusion: The overall risk of malignancy is significantly associated with older age, larger lesion, and the presence of atypia on core needle biopsy. The indications for surgical resection can be justified as age > 55 years and mass size > 10 mm, even in benign lesions in core biopsy. We suggest that close observation without surgery is sufficient for younger women with a small papilloma without atypia.

OFP-03 | Cardiovascular Pathology

OFP-03-001

Vitamin D deficiency and its correlation with morphological changes in peripheral arteries in the patients with a critical limb ischemia

S. Temirov, B. Magrupov*, B. Tursunov

*Center for the development of professional skills of medical staff, Republican Research Center of Emergency Medicine, Uzbekistan

Background & objectives: Assessment of the vitamin D deficiency and morphological changes of arterial wall may help to clarify the reasons of aggressive course of the peripheral arterial disease (PAD) in patients with diabetes mellitus (DM).

Methods: A morphological analysis performed in 44 arteries of 17 amputated lower limbs in patients with DM. Evaluated in 30 patients with CLI levels of Vitamin D, parathyroid hormone, calcium, phosphorus, and cholesterol in the blood. Patients divided into two groups: patients with CLI and DM (19) and patients with CLI by pure atherosclerotic lesion of peripheral arteries (11).

Results: In 14 out of 17 vessels, calcification of the middle layer of the tibial arteries was revealed. The level of vitamin D is 11.16 ng / ml, in patients with diabetes - 8.42 ng / ml and without diabetes - 17.10 ng / ml. In chronic renal failure, vitamin D levels were below normal. In patients with chronic renal failure and diabetes, severe vitamin D deficiency in 85.8%, and without diabetes - 33.3%. The content of calcium, phosphorus, cholesterol is within normal limits. The level of parathyroid hormone is increased in patients with diabetes - 79.17 ± 11.7, in patients without diabetes - 62.86 ± 22.11 pg / ml.

Conclusion: Thus, this allows one to suspect a direct connection between vitamin D deficiency and CLI, especially in patients with DM. Given the presence of severe medicalcinosis, apparently it is necessary to reconsider the algorithm of therapy in patients with DM with CLI, by including Vit D for long life therapy.

OFP-03-002

COVID-19-associated pathology of heart

A. Kukleva*, E. Kogan, O. Blagova, Y. Berezovskij

*Sechenov University, Russia

Background & objectives: New coronavirus infection is accompanied by the development of a wide range of cardiovascular lesions. We studied the clinical and morphological features of SARS-CoV-2-associated pathology of heart, determining the presence of viral RNA and proteins in myocardial tissue.

Methods: The study was based on 55 autopsies with a confirmed coronavirus RNA in the myocardium (paraffin blocks). The average age of the patients was 72.8±14.1 years. Men predominated (52,7%). Immunohistochemical determination of the surface markers of CD3, CD20, CD45, CD 68, perforin, TLR-4, TLR-9 and SARS-CoV-2 nucleocapsid and spike-protein were presented.

Results: Lymphocytic viral myocarditis was detected in 35 cases (63.3%), including 8 cases with lymphocytic pericarditis and 11 cases with lymphocytic endocarditis. Coronariitis was found in 37 cases (67%) and endotheliitis in 8 cases (14.5%). Lymphomacrophage infiltration of myocardium (more than 7 CD3+ T-lymphocytes, more than 14 CD45+ lymphocytes and more than 7 CD68+ macrophages per 1 mm2) were found in cases with myocarditis. Virus proteins were identified in macrophages of the inflammatory infiltrate and endothelial cells. Chronic ischemic heart disease and hypertensive cardiomyopathy were detected in 32 cases. There were also of sludge phenomenon, coronary artery thrombosis and DIC syndrome in all cases.

Conclusion: Morphological and molecular findings confirm that COVID-19-associated pathology of heart may be presented by viral myocarditis, endo- and pericarditis.

Funding: The research was supported by RFBR grant №20-315-90021

OFP-03-003

Post-Covid syndrome with persistence of SARS-Cov-2 in the myocardium and development of chronic myoendocarditis

E. Kogan*, O. Blagova, A. Kukleva, T. Demura, N. Zharkov, V. Fomin

*Sechenov University, Russia

Background & objectives: Possibility of the development of post-COVID-19 myoendocarditis is discussed in the literature. Purpose: to study morphological and molecular features of myoendocarditis and its possible mechanisms (including persistence of SARS-Cov-2 in the myocardium) in the long-term period after acute COVID-19.

Methods: Five males (age 45.8±14.4) diagnosed with post covid myocarditis were included in the study. The diagnosis of COVID-19 was confirmed by positive PCR in myocardial biopsy. The average time of admission after COVID-19 was 4 months. The diagnosis of myocarditis was confirmed by right ventricular endomyocardial biopsy. The PCR for cardiotropic viruses and PCR with immunohistochemical study for SARS-Cov2 were used

Results: Three patients had no evidence of heart disease prior to COVID-19; another two patients had moderate arrhythmias or heart failure in the absence of evidence of myocarditis. The symptoms started 2-9 months following COVID-19. SARS-Cov-2 RNA was detected in 5 biopsies. The longest period of virus persistence after COVID-19 was 9 months. By using antibodies to spike and nucleocapsid antigenes, coronavirus was detected in cardiomycytes, endothelium and macrophages. Lymphocytic myocarditis was confirmed immunohistochemically; giant cell myocarditis with atrial standstill was detected in one more case. Three patients had also signs of endocarditis, one case of infective endocarditis and two cases nonbacterial lymphocytic endocarditis with parietal thrombosis.

Conclusion: COVID-19 can lead to chronic myoedocarditis of varying severity. Post covid myocarditis manifests itself as isolated arrhythmias or systolic dysfunction with heart failure and characterized by prolonged persistence of coronavirus (up to 9 months) in combination with high immune activity. Prolonged post covid endocarditis associated with myocarditis, presents as non-bacterial thromboendocarditis or meets the criteria of infective endocarditis. SARS-Cov-2 persistence and autoimmune mechanisms play a significant role.

OFP-03-004

Aortic dissection and sudden cardiac death in the young

M. De Gaspari*, S. Rizzo, G. Thiene, C. Basso

*Università di Padova, Italy

Background & objectives: The link between bicuspid aortic valve (BAV) and aortic dissection (AD) was raised by early autopsy studies leading to the concept of BAV-related aortopathy. To assess the burden of BAV in juvenile SD and its histopathologic features.

Methods: The juvenile SCD Registry was searched for AD. Aortic diameters were measured at 4 different levels. Histopathological analysis was performed on the ascending aorta. Histopathologic changes of the tunica media in terms of mucoid extracellular matrix accumulation (MEMA), elastic fibre fragmentation and/or loss, and smooth muscle cell (SMC) nuclei loss were assessed.

Results: Among 816 SCD cases, 27 had aortic rupture including 24 AD (29.4%). Risk factors were BAV in 9 (37.5%), hypertension in 5 (21%), isolated isthmic coarctation in 2, pregnancy in 2, Marfan syndrome in 2, Turner Syndrome in 1, familial aortic dissection in 1 and idiopathic in 2. BAV-AD had significantly larger aortic diameters than BAV-non AD (P< 0.05). The proximal ascending aorta was significantly larger in Marfan-AD than in BAV-AD (p=0.03). Among histopathological changes of the tunica media, MEMA and elastic fragmentation were higher in Marfan (0.005 and 0.004) and SMC nuclei loss was higher in BAV (0.008). SMC apoptosis was higher in BAV than in controls (p= 0.004).

Conclusion: Juvenile SCD due to AD mostly recognizes a congenital or genetic background, with BAV identified in 37.5% of cases. Significantly smaller aortic diameters are observed in BAV than in Marfan syndrome patients and SMC loss is the more distinctive histopathologic feature.

OFP-04 | Cytopathology

OFP-04-001

Adequacy of cytology samples for molecular alterations in lung non-small cell carcinoma

K. Tilley*, M. Elgoweini

*NHS Greater Glasgow and Clyde, Department of Pathology, United Kingdom

Background & objectives: Ancillary studies are essential for therapeutic guidance in non-small cell lung carcinoma (NSCC). Cytology is frequently the only material available for mutational analysis. The aim was to evaluate the adequacy of cytological samples for mutational alteration detection in lung NSCC.

Methods: A search was performed electronically on the departmental database for cytology samples with a diagnosis of NSCC for 18 months from April 2019. The data collected from cytology reports included the amount and type of the sample, type and adequacy of tumour as well as the results of ancillary investigations including PDL1, ROS1, ALK and EGFR.

Results: 117 cytology samples with NSCC were received during this period. A total of 87 cases required mutational analysis. However, these tests were not requested by the reporting pathologist in 6/87 cases (7%) due to insufficient tumour content. 74 of the remaining 81 cases (91.4%) were fully adequate for all requested tests. 7/81 samples (8.6%) showed partial to complete inadequacy, with PDL1 having the highest inadequacy rate (100%) while EGFR showed the lowest (20%). 2 out of the 3 samples with complete inadequacy were from bronchial washings/ brushings in which 12 and 15mls of fluid was received. While the third, was 20mls from a lymph node by transbronchial fine needle aspiration.

Conclusion: Cytology is a minimally invasive approach for the diagnosis and staging of non-small cell lung carcinoma. Our results demonstrate that cytology samples can provide sufficient material for detection of mutational alterations especially when biopsy is not available.

OFP-04-002

The prevalence and age distribution of high-risk human papillomavirus infection from Turkish women with normal cytology

H. Seneldir*, G. Kir

*Istanbul Medeniyet University, Turkey

Background & objectives: The aim of this study was to investigate the prevalence and age distribution of high-risk human papillomavirus (hrHPV) infection from Turkish women with normal cytology.

Methods: Our study population consisted of 6273 women with normal cytology and adequate hrHPV molecular testing.

The cases were divided into 6 groups according to their age ranges as under 25 years old, 25-29 years old, 30-45 years old, 45-54, 55-65 and over 65 years old. Groups were compared with hrHPV positivity and type 16/18 positivity.

Results: HrHPV was detected in 689 (10.98 %) of 6273 cases. The positivity of hrHPV were 26.3% in group 1 (<25 years), 16.83% in group 2 (25-29 years), 10.7% in group 3 (30-45 years), 8.46% in group 4 (45-54 years), 10.72% in group 5 (55-65 years) and 4.65% in group 6 (> 65). There was statistically significant difference in the rates of hrHPV between group1 and the other groups (p <0.05). There was statistically significant difference in the rates of hrHPV of group2 and the other groups (p <0.05) . There was statistically significant difference in the rates of type 16 between groups 1 and the other groups (p <0.05) .

Conclusion: According to meta-analysis studies, hrHPV positivity was reported to be approximately 6.6% in women with normal cytology. This rate ranges from 1.4% to 25.6%; more frequently in societies with low-medium socioeconomic status. In our study, regardless of age groups, this rate was found to be 10.98%, and it can be found in accordance with the literature.

OFP-04-003

The results of human papillomavirus testing and cytology with reflex mRNA expression analysis in the practice of liquid-based cytology in postmenopausal women

N. Melnikova*, I. Antonova, N. Bolotina, N. Akopova, N. Yarovaya, E. Shayhaev, M. Zakharenko, V. Bozhenko

*RSCRR, Russia

Background & objectives: The goal of this study was to determine the accuracy of liquid-based Pap test and HPV genotyping for high-grade squamous intraepithelial lesions (HSIL) or severe and opportunity of the reflex mRNA expression analysis by quantitative PCR among postmenopausal women.

Methods: Histological follow-up results of 31 postmenopausal women with Pap test CellPrep and HPV testing results with HPV QUANT-21 Quantitative Real-Time PCR Kit were analysed. All cases were tested for the expression of the 21 genes (Ki-67, STK-15, CCNB1, CCND1, MYC, MYBL2, P16INK4A, PTEN, BIRC5, BCL2, BAG1, TERT, NDRG1, ESR1, PGR, HER2, GRB7, MGB1, MMP11, CTSL2, CD68) in a residual media.

Results: We discovered that in histologically confirmed HSIL cases (n=10) there was the highest prevalence (100%) of hrHPV types with significant load of hrHPV 16 and 33. HPV-associated were 2 (100%) squamous cell carcinomas and 1 (50%) endocervical adenocarcinomas. At the threshold of LSIL positivity for histologically confirmed HSIL +, considering false positive conclusions about the presence of HPV in the case of a benign process (n = 10), the sensitivity was 88.24% for HPV DNA testing and 87.50% for cytology. The combined evaluation of the 21- gene expression panel allows, according to the discriminant analysis, to carry out the correct differentiation for HSIL+ from LSIL or less in 100%.

Conclusion: The evaluation of Pap test CellPrep media for hrHPV genotyping with viral load and cytology among postmenopausal women complement each other and therefore increase the diagnostic sensitivity of precancerous processes and cervical cancer, mainly squamous epithelial origin. The expression analysis of 21-gene panel by quantitative PCR may introduce like a reflex testing for severe cervical lesions including endocervical adenocarcinoma without association with HPV and requires further studying.

OFP-04-004

Metastatic Merkel Cell Carcinoma presenting as a solid pancreatic mass

J. Madeira*, J. Gama, F. Ramalhosa, C. Faria, G. Fernandes, M.A. Cipriano

*Serviço de Anatomia Patológica, Centro Hospitalar e Universtário de Coimbra, Portugal

Background & objectives: Merkel Cell Carcinoma (MCC) is a rare skin cancer that frequently exhibits locoregional and distant recurrence, without a clearly defined treatment. Few cases of pancreatic metastases from MCC have been reported in the literature.

Methods: We present a case of a 63-year-old man with an enlarged right inguinal lymph node. Excisional biopsy diagnosed a metastatic MCC. Additional workup did not reveal the primary lesion and he was submitted to adjuvant radiotherapy. A follow-up computed tomography(CT) scan revealed a tissue densification in the right inguinal region and a 12x9cm mass involving the pancreatic body and tail.

Results: A positron emission tomography (PET) scan showed intense pancreatic uptake. An endoscopic ultrasound (EUS) was performed, showing an 8.6x8.3cm, hypoecoic, heterogeneous, ill-circumscribed lesion with local vascular spread. EUS-elastography revealed a predominantly hard pattern. A EUS-guided fine-needle aspiration with cytoblock was performed. Morphologically, the tumour displayed neuroendocrine architecture with mostly solid formations of small to medium round cells, with a high nuclear-cytoplasm ratio. It was mitotically highly active (>10 mitoses/mm2) and contained abundant necrosis. Immunostains for chromogranin and synaptophysin showed granular cytoplasmic staining and cytokeratin 20 demonstrated a dot-like perinuclear pattern, supporting the diagnosis of metastatic MCC. The patient was evaluated for systemic therapy.

Conclusion: MCC is a rare and aggressive neuroendocrine tumour of the skin that typically affects Caucasian patients over the age of 65 years. It commonly appears as a red to violaceous, indurated dome-shaped nodule or plaque on sun-exposed areas of the head and neck, with a high incidence of local recurrence, regional lymph node, and distant metastases. Metastatic spread to the pancreas is exceptional and its impact on prognosis and surveillance is unknown.

OFP-04-005

Pleomorphic adenoma: What features accompany false-positive and false-negative cases in cytological specimens?

I. Kholova*, E. Tommola, S. Tommola

*Pathology Department, Fimlab Laboratories, Tampere, Finland

Background & objectives: Fine needle aspiration (FNA) is a well-established tool for preoperative diagnosis for salivary gland lesions. Pleomorphic adenoma (PA) is the most common salivary gland tumour comprising 45-74% of all salivary gland tumours with diagnostic accuracy of FNA to be 89.5-96.2%.

Methods: Specimens from parotid gland and submandibular gland with both cytological diagnosis and histological follow-up were searched over a ten-year-period (2009–2018) from a laboratory information system of Pathology Department, Fimlab Laboratories, Tampere and PA cytological and histological diagnoses were matched to determine concordant and discordant cases.

Results: Either cytological or histological PA diagnosis was given in 189 cases with 174 concordant cases and 14 discordant cases: 4 false-positive cases and 10 false-negative cases. Cell type predominance was more often myoepithelial in true-positive cases (65%, 13/20) and epithelial both in false-negative cases (73%, 8/11, p=0.001) and in false-positive cases (75%, 3/4, p=0.013). Only 10% (2/20) of true positive cases did not show matrix in cytology whereas 64% (7/11) of false-negative cases did not show matrix in cytology (p<0.001). Nuclear changes were rare in true positive cases (10%, 2/20) and common in false-negative cases (73%, 8/11, p=0.002) and false positive cases (75%, 3/4, p=0.018).

Conclusion: Statistical analysis showed diagnostic accuracy of 96.6% for FNA cytology regarding PA diagnosis. Sensitivity and specificity were, respectively, 94.6% and 98.2%. Positive predictive value and negative predictive value were, respectively, 97.8% and 95.6%.

Funding: VTR X5211

OFP-04-006

Cytomorphology, immunophenotype and cytogenetic profile of leukemic serous effusions

K. Kaur*, T. Patel, S. Patra, P. Trivedi

*Gujarat cancer and research institute, India

Background & objectives: Serous effusions in leukaemia can be due to infections, therapy, volume overload, lymphatic obstruction or malignancy having implications on treatment and mortality. The objective of the present study is to highlight the cytomorphology, immunophenotype and cytogenetics in leukemic serous effusions.

Methods: Present study is retrospective and descriptive. We reviewed all the serous effusions which were reported as suspicious or positive of leukemic infiltration from 2016 to 2019 for cytomorphological features. CSF and effusions involved by lymphomas were excluded. Cyto-diagnosis was compared with primary proven diagnosis (by ancillary techniques) and disconcordant cases were analysed.

Results: Out of total 9723 effusions, only 0.4% (n=40) showed leukemic involvement and included 9 cases of AML, 3 of B-ALL, 13 T-ALL, 2 MPAL, 6 CML, 5CLL, one each of CMML and AML with myelodysplasia. The most common site of involvement was the pleural cavity (n =30), followed by the peritoneal cavity (n=7) and the pericardial cavity (n =3). T –ALL (41.9%) was the most common leukaemia involving pleural fluid followed by AML (23.3%). CML (42.8%) was the most common leukaemia involving the ascitic fluid followed by B-ALL (28.6%). Accurate diagnosis was given on cytomorphology in 72.5% (29/40) cases and 15.0% (6/40) were reported as NHL.

Conclusion: Cytology is an effective tool available to make a diagnosis of LSE. Nuclear indentations in large atypical cells and cells with eosinophilic granular cytoplasm with sparse or abundant eosinophils in the background are an important clue in favour of leukaemia over lymphoma.

OFP-04-007

Comparison of conventional and liquid-based cytology using The Paris System for reporting Urinary Cytology

D. Goutas*, K. Savvidou, K. Vrettou, E. Meletis, P. Levis, C. Constantinides, A.C. Lazaris, P. Mikou

*First Department of Pathology, School of Medicine, The National and Kapodistrian University of Athens - "Laikon" General Hospital of Athens, Greece

Background & objectives: This is a retrospective study conducted in the Cytopathology Department of Laiko Hospital in order to compare the conventional cytospin method and the liquid-based urinary cytology in diagnosing bladder cancer by using The Paris System of urinary cytology classification.

Methods: We have searched our laboratory files in 2020 and we have retrieved 100 cases of void urinary cytology classified according TPS and including 35 TPS2, 25 TPS3, 20 TPS4 and 20 TPS5 cases. The number of cases chosen from each category was arbitrarily decided in order to compare the two methods in a meaningful manner.

Results: In the study material risk of malignancy (ROM) was 5.7% for TPS2, 28% for TPS3, 55% for TPS4 and 95% for TPS5. Agreement rate between cytospin and the original diagnosis was 86% and between Thinprep and the original diagnosis 82%. No significant differences were observed among the two techniques and their combination regarding sensitivity and specificity, with a mild advantage for the cytospin method. Intra-observer reproducibility and repeatability for the TPS was high.

Conclusion: Our study demonstrated that no significant differences exist concerning sensitivity and specificity among the two techniques used, when applying the TPS criteria. The TPS is a reliable classification scheme for either conventional/cytospin or liquid-based cytology or even the combination of them.

OFP-04-008

Immunocytochemical expression of Galectin 3 in the thyroid fine-needle aspiration (FNA) specimens

S. Erdogan-Durmus*

*Basaksehir Cam and Sakura City Hospital, Department of Pathology, Cytopathology Division, Turkey

Background & objectives: Galectin3 is a human lectin that is related to malignant transformation in thyroid gland and its expression in thyroid carcinomas was known. The aim of this study to examine the diagnostic utility of Galectin3 in the thyroid FNA specimens.

Methods: Fifteen papillary thyroid carcinomas (PTC) and 5 benign follicular nodules that diagnosed cytolomorphologically from 19 patients were evaluated. All slides prepared by liquid based cytology (LBC) (Surepath, BD®) and there were no cell blocks.

Immunocytochemical (ICC) analysis was performed with avidin-biotin-peroxidase complex on second slides that prepared by LBC, using the antibody Galectin 3 (Ventana Medical Systems®, Clon: 9C4).

Results: The mean age of patients was 44.1 ± 14.8 (Range 22-72 years). There were 4 male 15 female patients. Fourteen (93.3%) of the 15 PTC aspirates showed strong cytoplasmic and/or nuclear immunoreactivity for Galectin 3. The all of benign aspirates were negative. Focal positivity was seen in 2 of 14 immunoreactive PTC aspirates. If we consider cytomorphology the gold standard in this restricted study group the sensitivity and the specificity for Galectin 3 immunostainig were 93.3% and 100%, respectively.

Conclusion: A positive immunostain for Galectin 3 on a thyroid FNA is a strong supporter for PTC, whereas a negative result for Galectin 3 favor a benign nodule. With LBC additional slides can be obtained for additional studies such as immunocytochemistry. The Galectin 3 can be effectively applied to LBC slides of thyroid FNAs and can be a valuable ancillary marker in the cytologic diagnosis of PTC especially in FNAs with limited material.

OFP-04-009

Cytohistological correlation of salivary gland lesions

J. Dos Santos*, G. Miranda, T. Amaro, F. Magalhães, M. Honavar

*Serviço de Anatomia Patológica, Hospital Pedro Hispano (ULSM), Portugal

Background & objectives: Fine needle aspiration (FNA) is an accurate minimally invasive technique used in the management of salivary gland tumours. Our aim is to study the utility of FNA in the diagnosis of salivary glands lesions through cytohistological correlation.

Methods: A total of 124 patients (69 women and 55 men; aged 22-92 years) with salivary gland lesions underwent surgery between 2010 and 2020: 68 had previous FNA. These FNA diagnosis were categorized according to the The Milan System for Reporting Salivary Gland Cytopathology and correlated with the surgical specimen diagnosis. The risk of malignancy (ROM) for each category was determined.

Results: FNA results: 11 non-diagnostic (ND), 1 non-neoplastic (NN), 3 atypia of undetermined significance (AUS), 44 benign neoplasms (BN), 8 salivary gland of uncertain malignant potential (SUMP), 0 suspicious for malignancy (SM) and 1 malignant (M). Histopathological follow-up: 55 benign tumours (32 pleomorphic adenomas, 16 Warthin tumours, 3 basal cell adenomas, 1 canalicular adenoma, 1 papilloma, 1 myoepithelioma, 1 sialolipoma), 6 malignant tumours (2 acinic cell carcinomas, 3 mucoepidermoid carcinomas, 1 carcinoma ex adenoma pleomorphic) and 7 inflammatory conditions. Excluding the ND, AUS and SUMP, 41 out of 46 (89%) cytological diagnoses had concordant histology. ROM for each category: ND 9.1%, NN 100%; AUS 0%; BN 6.8%, SUMP 0%, M 100%.

Conclusion: The percentage of concordant cases are within the range of published data. ROM by categories were different from the ones recommended by The Milan System for Reporting Salivary Gland Cytopathology. These results can be attributed, at least in part, to the small sample size. Most of the salivary gland lesions can be accurately diagnosed via FNA. In difficult cases, FNA is a useful diagnostic tool for risk stratification of these lesions.

OFP-04-010

Secretory carcinoma of the parotid gland: a tumour with many diagnostic clues

A. Ali*, A. Kempalingaiah, F. Al-Hashimi

*Broomfield Hospital, United Kingdom

Background & objectives: Secretory carcinoma is a rare tumour mostly affecting the parotid gland. It remains under-reported in the literature. We present a secretory carcinoma diagnosed on a cytology to increase awareness of its unique cytological features, key diagnostic, and molecular characteristics.

Methods: An ultrasound-guided fine needle aspiration of a parotid lump was obtained from a non-smoker elderly woman with past medical history of breast cancer. She presented with a history of a unilateral progressively enlarging parotid lump over several months.

Results: The cytology sample showed clusters and papillary configuration of small to medium sized uniform cells with vacuolated cytoplasm. The lesions cells characteristically lacked zymogen granules. The cells exhibit prominent hobnailing. The cells show pale vacuolated to eosinophilic cytoplasm. Immunocytochemistry showed positive staining for S100 and CK7, and patchy positivity for Mammoglobin. The cells were negative staining for DOG-1. Molecular testing confirmed the diagnostic ETV6-NTRK3 fusion.

Conclusion: Cytological diagnosis of salivary gland tumours possess major challenge, even for head and neck specialists. Diagnosing a rare tumour like secretory carcinoma requires a high index of suspicion and awareness of its characteristic cytological and histological diagnostic features. Confirming ETV6-NTRK3 fusion remains the gold standard for diagnosis, which can be done on both cell block and tissue samples.

OFP-04-011

Simulation module for palpation of lesions suitable for fine needle aspiration cytology. Validation study

E. Alcaraz-Mateos*, F. Stefano-Galdame, F. Caballero-Alemán, M.J. Parraga-Ramirez, E. Poblet

*Department of Pathology, Morales Meseguer University Hospital, Spain

Background & objectives: Physical examination continues to be essential in clinical diagnosis. Adequate examination is a basic prerequisite for performing the fine needle aspiration (FNA) cytology technique on palpable lesions. With the goal of contributing to medical training, a simulation module was designed.

Methods: Taking advantage of the FioNA® simulator for FNA, modifications to the model were made. Handmade simulated lesions were designed, creating different clinical scenarios (neoplasms, cysts, and adenopathies) and providing a variety of tactile sensations (shape/size/consistency/demarcation/movement). It was evaluated for face and content validity by 30 specialists. Additionally, 23 third-year medical students were assessed after receiving basic theoretical training in palpation.

Results: The external aspect (appearance, location, degree of realism, and tactile sensation) of the modified model used to acquire palpation skills received an average rating of 8.9/10 (σ 0,78); the item that received the lowest valuation was the feeling when palpating (8.4/10; σ 1.9). The educational value (use for training, variety of exercises, and preparation for real-life procedures) was validated by all of the specialists. All but one of the physicians rated the variety of exercises as adequate. Moreover, the simulator was perceived as intuitive (9.2/10).

Regarding participant assessment, average student scores were 3.6/5 (range 1.2-4.6; σ 0.97); only 4 students received an unsatisfactory result (a score less than 2.5)

Conclusion: It is possible to adapt a palpation module to the FioNA® simulator for skills assessment.

This study showed face and content validity of this prototype for exploratory purposes.

Given that FNA is a routine medical procedure, formal training to acquire palpation skills seems appropriate.

OFP-04-012

Malignancy rate of atypia of undetermined significance/follicular lesion of undetermined significance in thyroid FNA in Greater Vancouver, Canada: a preliminary analysis

L. Ali, S. Koonmee, O. Ondic, K. Pivovarcikova, C. Aphivatanasiri, P. Ungarreevittaya, A. Khayat, R. Bhan, J. Rogola, R. Alaghehbandan*

*Department of Pathology and Laboratory Medicine, University of British Columbia, Royal Columbian Hospital, Canada

Background & objectives: Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance (AUS/FLUS) is a challenging category comprised of a heterogeneous group of lesions. This study’s objective was to evaluate the malignancy rate of the AUS/FLUS in fine needle aspiration (FNA) of thyroid nodules.

Methods: This is a retrospective cross-sectional study assessing malignancy rate in thyroid nodules FNA performed in Fraser Health in Greater Vancouver area, with a 1.8 million population, during a six-year period (2014-2019). FNA results were correlated with clinical outcome in subsequent years including repeat FNA, surgery, and clinical/imaging follow-up. Clinical and radiologic factors were compared to identify malignancy-related features.

Results: This is a preliminary analysis of 61 cases of AUS/FLUS. Mean age was 60.2 years, with 50/61 (82%) being female. Repeat FNA was performed on 21 (34.4%) nodules, and 30 (49.2%) underwent surgery. Of 21 repeat FNAs, 5 were AUS/FLUS, 7 benign, and 5 suspicious for follicular neoplasm or malignancy. 7 of 30 patients who underwent immediate surgery had papillary or follicular thyroid carcinoma. The upgrade rate to malignancy was 11.5% (7/61). There were no significant differences in age, sex, and nodule size between benign and malignant cases. The rate of malignancy was 14.3% (3/21) in patients underwent surgery, while it was 10% (4/40) for patients underwent repeat FNA (P>0.05).

Conclusion: The malignancy rate of AUS/FLUS in the study is consistent with the recommended range proposed by the 2017 Bethesda System for Reporting Thyroid Cytopathology. Demographic and radiologic findings were not significantly associated with upgrade malignancy risk. No significant difference was found in malignancy risk between those who underwent immediate operation following the AUS/FLUS diagnosis versus patients with repeated FNA after the initial diagnosis.

OFP-05 | Dermatopathology

OFP-05-001

Cutaneous metastases of internal malignancies: a single institution experience

A. Vernemmen*, X. Li, G. Roemen, A. zur Hausen, V. Winnepenninckx, I. Samarska

*Department of Pathology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center+, The Netherlands

Background & objectives: Cutaneous metastases of internal malignancies are infrequent. Therefore, the diagnosis can sometimes be challenging, especially in cases with an unknown primary cancer. This clinicopathological study aimed to review the cases of cutaneous metastases of internal malignancies in our institution.

Methods: The retrospective review included all cases of skin metastases from non-cutaneous primary neoplasms diagnosed in the Department of Pathology at the Maastricht University Medical Center+ from 2006 to 2021. The clinicopathological data were collected, and appropriate immunohistochemical or molecular procedures were performed to confirm the primary origin of the metastases.

Results: We identified 132 cases of cutaneous metastases of non-cutaneous internal malignancies (74 female; 31 male patients; median age of 68.5 years [range 29 to 90 years]). Among the female patients, the most common primary tumour was breast cancer (46.2%), followed by lung (15.0%), tumours of gynecological (7.5%) and gastrointestinal origin (5.4%). Among the male patients, the most common primary sites were gastrointestinal and lung origin (altogether 46% of the specimen). In the majority of the cases, a primary tumour was known. However, in 11 cases, the cutaneous metastasis seemed to be the first presentation of the clinically silent malignancy (8.3%), leading to the diagnosis of a primary non-cutaneous malignancy.

Conclusion: Breast and gynecological tumours are the leading origins of cutaneous metastases in female patients, which is in line with previously published data. Lung and gastrointestinal cancer are among the most common primary tumours, demonstrating skin metastases in both female and male patients. Infrequently, cutaneous manifestation could be the first sign of a clinically silent visceral malignancy; therefore, broad immunohistochemical profiling and a high level of awareness are necessary for a precise diagnosis.

OFP-05-002

Nuclear protein in testis (NUT) expression and loss of C-terminus yes-associated protein 1 (YAP1) in a subset of hidradenomas

A. Sykaras*, C. Vourlakou, E. Gioti, N. Stavrinou, I. Nitsios, C. Kouvidou

*Evangelismos General Hospital, Greece

Background & objectives: YAP1-NUTM1 fusion transcripts were recently identified in poromas, porocarcinomas, poroid hidradenomas and poroid hidradenocarcinomas. Adnexal tumours harbouring YAP1-NUTM1 fusions display immunohistochemical loss of YAP1 C-terminus and expression of NUT. Our aim was to analyse YAP1 and NUT expression in hidradenomas.

Methods: Our cohort included sixteen hidradenomas. We performed IHC for YAP1 (using an antibody specific for C-terminus YAP1) and NUT on formalin-fixed paraffin embedded sections. We considered as YAP1 C-terminus negative cases with total loss of YAP1 C-terminus in tumour cells and positive staining in internal control (stromal and endothelial cells). NUT1 positive cases displayed strong and diffuse nuclear NUT expression.

Results: Four hidradenomas (4/16) had abolished YAP1 C-terminus expression whereas the rest (12/16) displayed cytoplasmic and nuclear (to a lesser extent) staining of comparable intensity to internal positive control. Robust nuclear NUT expression was detected in all (4/4) YAP1-negative hidradenomas. All cases that retained YAP1 C-terminus expression were negative for NUT (0/12). In summary, 25% of hidradenomas had a YAP1 negative/ NUT positive immunohistochemical profile.

Conclusion: YAP1-NUTM1 fusions are implicated in the pathogenesis of benign and malignant adnexal tumours. Immunohistochemical expression of NUT with parallel loss of YAP1 C-terminus in these tumours is a useful diagnostic tool and represents a surrogate marker for the presence of YAP1-NUTM1 fusion. Our findings indicate that a YAP1-NUTM1 fusion may be present in hidradenomas. Combined immunohistochemical and molecular analysis facilitates the diagnosis and may shed light to the genetic events driving the development of hidradenomas.

OFP-05-004

Clinicopathologic features and overal survival relationship in metastatic melanoma

S. Kestel*, P. Uyar Göçün, Ö. Erdem

*Gazi University Hospital, Pathology Department, Turkey

Background & objectives: Melanoma can metastasize both hematogenous and lymphatic routes. Five-year survival for melanoma with distant metastasis was reported as 22.5%. The present study evaluates the relationship between clinicopathologic parameters and overall survival for metastatic melanoma patients.

Methods: In this study, 122 metastatic melanoma cases (45 F, 77 M) that were metastatic at the time of diagnosis or consulted for molecular pathological analysis in the Gazi University Hospital, Pathology Department, were included. Pigmentation, necrosis, perivascular pseudorosette, tumour-infiltrating lymphocytes (TILs), pleomorphism, cell type, cytoplasmic and nuclear features, mitotic count were evaluated. Survival analysis was calculated using the Kaplan-Meier method.

Results: The mean age of diagnosis at the time of metastasis was 55.95 ± 1.35 years (range 19-89). At the end of the study, 26 (21.3%) of the patients were alive, whereas 96 (78.7%) were deceased. The diagnosis age of greater than 60 years had shorter overall survival than the patients with the diagnosis age of 31-60 years (p=0.013). Lung and central nervous system metastasis had a worse overall survival than lymph node, skin, and subcutaneous soft tissue. In contrast, liver, bone marrow, and paranasal sinus metastasis had shorter overall survival than lymph node metastasis. Perivascular pseudorosette formation was noticed in 64 metastatic melanoma cases and reduced overall survival time (p=0.002).

Conclusion: Ishida et al. described the perivascular pseudorosette formation of primary melanoma as a case report. Lugassy and Barnhill reported that angiotropism is seen more frequently in metastatic melanoma than melanoma without metastasis. This difference leads to an argument that melanoma metastasis pathways could include other options besides lymphovascular invasion. The reduced overall survival in metastatic melanoma that formed perivascular pseudorosette might support the idea of melanoma extravascular metastasis pathway in which melanocytes have a perivascular arrangement and show angiotropism.

OFP-05-005

NTRK - fused spitz tumours – histopathological, immunohistochemical and molecular features

H. Jawad*, K. Pilson, A. Casey, S. Ni Mhaolcatha, S. L McCarron, C. O'Brien, S. Finn, C.C. Heffron

*Cork University Hospital, Ireland

Background & objectives: Kinase fusions have been identified in Spitz tumours with subsequent studies aiming to characterise morphological features which may correspond to these fusions. The aim of our study was to examine the immunohistochemical and histopathological features of NTRK-fused Spitz tumours.

Methods: Immunohistochemical analysis of NTRK, ALK, ROS1 and BRAF with follow up molecular analysis was performed on 153 Spitz tumours over 8 years. We examined the histopathological features of the nine Spitz lesions with an NTRK fusion and compared them with those with ALK (7 cases) or ROS1 fusions (9 cases) and those without a kinase fusion to determine discriminating features.

Results: NTRK fusions were identified in 5.8% (9/153) of our Spitz tumours. The majority of Spitz tumours with an NTRK fusion occured on the extremities (77.8%). The majority of the NTRK-fused tumours (55.6%) were compound with spindle cell morphology. Filigree-like rete ridges were noticed in 55.6% of the lesions. 71.4% of the cases demonstrated a lobulated nest while only 16.7 % of the cases shows rosette-like configuration. In all the cases, immunohistochemistry for the pan NTRK antibody showed membranous and cytoplasmic staining in all cells. In 88.9% of the cases the intensity of the staining was strong (3+). Molecular studies confirmed 8/9 of the cases to have an NTRK fusion.

Conclusion: NTRK-fused Spitz tumours have distinctive histological features including lobulated nests and filigree-like rete ridges. The pan NTRK immunohistochemical antibody showed strong membranous and cytoplasmic staining in lesional cells and thus may be a useful tool in the arsenal in the diagnosis of Spitz tumours particularly when access to molecular testing may be limited.

OFP-05-006

Retrospective study of 31 cases of pityriasis lichenoides from a Portuguese dermatopathology department and review of the literature

C. Faria*, J. Calvão, O. Tellechea, M.J. Julião, J.C. Cardoso

*Centro Hospitalar e Universitário, Portugal

Background & objectives: Pityriasis lichenoides is an infrequent dermatosis whose clinical spectrum encompasses an acute form characterized by haemorrhagic, crusted and/or necrotic papules that resolve with varioliform scars, and a chronic form presenting with scaly papules. Histopathological diagnosis can be challenging.

Methods: We describe 31 patients with histopathologically confirmed diagnosis of pityriasis lichenoides diagnosed from 2010 to 2020. Our series had a female predilection, representing 61% of total patients and a broad age distribution at the time of diagnosis, between 5 and 67 years-old. Twenty three percent of the cases were diagnosed at paediatric age.

Results: Pityriases lichenoides et varioliformis acuta (PLEVA) represents 19,4% (six cases), including a 5-year-old boy and a 67 year-old woman. Histopathology revealed a dense dermal inflammatory cell infiltrate with extension into the epidermis, showing basal vacuolar change, focal spongiosis, apoptotic keratinocytes and focal epidermal necrosis. Edema of the papillary dermis and leukocytoclastic vasculitis were also common findings.

Pytiriasis lichenoides chronica (PLC) accounts for 80,6% of cases, with characteristic macules and papules with central mica-like scale. Microscopically it showed a predominantly lymphocytic perivascular infiltrate without vasculitis and minimal exocytosis of lymphocytes. Occasional extravasated erythrocytes were present.

No cases of the ulceronecrotic variant of PLEVA were reported and no cases progressed to lymphoma.

Conclusion: The diagnosis can be difficult, because clinical correlation is essential to confirm both forms, especially PLC, that presents more subtle histopathological findings. Erythema multiforme and lymphomatoid papulosis are the main differential diagnosis in PLEVA.

Our study also reveals that the majority of cases presented exacerbations and remissions in both forms of the disease (81%) with appearance of new lesions that were responsive to treatment, predominantly oral antibiotics and topical corticosteroids.

OFP-05-007

Primary and Metastatic Cutaneous Lymphomas: a 10-year study from a tertiary center in Coimbra

C. Faria*, J. Calvão, O. Tellechea, M.J. Julião, J.C. Cardoso

*Centro Hospitalar e Universitário, Portugal

Background & objectives: Primary cutaneous lymphomas represent a diverse group of extranodal lymphomas and should be distinguished from secondary involvement, although the histopathology might be identical in both cases. Careful assessment of histology and clinical features are the mainstay of diagnosis.

Methods: Retrospective study of 118 patients with histopathological diagnosis of primary and metastatic cutaneous lymphomas from 2010 to 2020. There was not a significant sex predilection, with 51,6% being male patients; the youngest patient had 7 years old and the oldest one had 90 years old at the time of diagnosis.

Results: Primary cutaneous lymphomas represent 68,6%, while secondary involvement represents 31,4%. Mycosis fungoides is the most common diagnosis (33%), followed by primary cutaneous CD30-positive T-cell lymphoproliferative disorders (16,9%). Primary cutaneous diffuse large B-cell lymphoma, leg type represents 5,9%, primary cutaneous follicle center lymphoma and peripheral T-cell lymphoma NOS account for 3,4% each, extranodal marginal zone lymphoma 2,5%, and intravascular large B-cell lymphoma, subcutaneous panniculitis-like T-cell lymphoma, extranodal NK/T-cell lymphoma, nasal type, and primary cutaneous gamma delta T-cell lymphoma represent 0,8% each.

Diffuse large B-cell lymphoma (11%), follicular lymphoma (7,6%), extranodal marginal zone lymphoma (3,4%) and angioimmunoblastic T-cell lymphoma (1,7%) were the most frequent cases with secondary skin involvement.

Conclusion: The majority of primary cutaneous lymphomas has a good prognosis. In our series, mortality rate was 17,3% for primary lymphomas associated to progression of disease and late stage diagnosis and 54% for secondary involvement.

Primary cutaneous or secondary diffuse large B-cell lymphoma and peripheral T-cell lymphoma NOS had the worse outcome. However, more than half of mycosis fungoides had recurrent disease, seven of each died due to other comorbidities related to immunosuppression, such as organ transplantation and other non-lymphoproliferative neoplasms.

OFP-05-008

Detection of NTRK fusions in atypical Spitz tumours

R. Cappellesso*, S. Simi, F. Castiglione, F. Nozzoli, V. De Giorgi, F. Zito Marino, R. Franco, D. Massi, Italian Melanoma Intergroup (IMI) study group

*University Hospital of Padua, Italy

Background & objectives: Atypical Spitz tumours (AST) are melanocytic proliferations with uncertain malignant potential. Activating NTRK1/NTRK3 fusions act as oncogenic events in Spitz lesions and are targetable with kinase inhibitors. We aimed to define the optimal approach for their detection in ASTs.

Methods: 180 FFPE AST samples were screened with pan-TRK immunohistochemistry. The positive cases were further analysed with FISH (NTRK1, NTRK2, and NTRK3 probes), two different NGS panels for solid tumours, and specific real time RT-PCR panel to confirm the presence of NTRK fusions.

Results: Overall, 26 ASTs showed pan-TRK immunostaining. NTRK1 fusions were detected in 14 of these cases showing cytoplasmic immunoreaction, whereas NTRK3 was detected in the only case showing nuclear immunoreaction. The molecular tests resulted all positive in only 2 ASTs (included the NTRK3 translocated one), whereas FISH and real time RT-PCR were concurrently positive in another 2 cases. In 6 ASTs NTRK1 fusions were detected only by FISH, in 3 cases by both NGS and real time RT-PCR, and in the remaining one only by real time RT-PCR.

Conclusion: The frequency of NTRK fusions in ASTs is 8%, with a clear prevalence of NTRK1 compared to NTRK3 alterations. Pan-TRK immunohistochemistry is a good test to screen ASTs. The confirmation of NTRK fusions may require the use of different techniques.

OFP-05-009

Reflectance confocal microscopy (RCM) features of inflammatory skin disorders overlap with horizontal histopathological sections (HHSs)

R. Caltabiano*, G. Broggi, F. Lacarrubba, A.E. Verzì, G. Micali

*University of Catania Section of Anatomic Pathology, Italy

Background & objectives: RCM shows the epidermal layers and papillary dermis with a horizontal “point of view”. The aim of this study was to compare the RCM features of skin inflammatory diseases with HHSs, that reflected the same observation plane as RCM.

Methods: Two 5-mm punch biopsies were performed in 19 selected patients (7 females and 12 males) affected by psoriasis (five cases), eczema (five cases), discoid lupus erythematosus (DLE) (3 cases) and molluscum contagiosum (MC) (6 cases). One biopsy was processed for vertical histopathology for diagnostic confirmation, one underwent extra paraffin-embedding for horizontal histopathology.

Results: A strong correlation between RCM features and HHSs was seen. RCM in eczema cases showed at the level of stratum spinosum hyporefractive areas with broadband intercellular spaces, with scattered round-polygonal mildly refractive cells, reflecting the spongiotic features and the presence of scattered lymphocytes intermingled with keratinocytes, seen on HHSs. On both techniques, dermal psoriasiform papillae were superficially visible, dilated and filled with tortuous vessels. DLE RCM epidermal images showed roundish areas filled with hyper-refractive amorphous material (follicular plugging) and partial disappearance of the dermal papillae. RCM in MC cases exhibited roundish lobules filled with bright cells, corresponding to the histopathological lobulated squamous-cell hyperplasia, composed of large keratinocytes with Henderson-Paterson bodies.

Conclusion: This comparative study between horizontal histopathology and RCM imaging is useful to further validate the diagnostic use of RCM in dermatological clinical practice. The possibility to create a panel of morphological matches between these two techniques may also improve the accuracy of the dermatologists in choosing the best site for biopsy sample, or in promptly recognizing a potential relapse of disease.

OFP-05-010

Does the sampling method have any impact on the evaluation of skin biopsies?

B. Calim Gurbuz*, B. Aytekin, T. Soylemez Akkurt

*Basaksehir Cam and Sakura City Hospital, Turkey

Background & objectives: Skin diseases are common health problems. They are evaluated with punch biopsies, especially in clinically challenging situations. There are different sampling methods for skin biopsies. The aim of this study is to compare two different techniques with the clinicopathologic findings.

Methods: 608 skin punch biopsies of 529 patients between May 2020 and March 2021 were included in the study. 339 biopsies were sampled without cutting, while 269 biopsies were cut into two equal parts. The site, diameter, preliminary diagnosis were collected from the clinical data. The histopathological findings were obtained from pathology reports. The results were statistically analysed.

Results: Of the 529 patients, 54% were female and the average age was 42,8+ 19,8 (range 0-91). The lower extremity was the most common biopsy site (229 patients, 43%). The average biopsy diameter was 1.05 cm (range 0.1-2 cm). Perivascular dermatitis was the most common histopathologic diagnosis (176 biopsies, 29%). The number of serial sections were significantly lower in the group which underwent macroscopic cutting technique (p=0.001). Clinicopathologic discordance was seen in 103 biopsies (17%). More sections were significantly requested in case of clinicopathologic incompatibility (p=0.01). When compared to interphase and psoriasiform group, more extra sections were evaluated in bullous dermatitis (p=0.01).

Conclusion: In this study, we evaluated big number of biopsies with different sampling methods. Our findings suggested that dividing biopsies into two equal parts reduced the necessity of extra sections. Besides the sampling methods, one of the reason for extra sections was clinicopathologic discordance. The other reason was some lesions tend to appear in focal areas and they can show up in extra sections. If suitable conditions are provided, applying the cutting method can reduce expenses and shorten pathology report time.

OFP-06 | Digestive Diseases Pathology - GI

OFP-06-001

MLH1/PMS2 expression could tell classical NTRKs fusion in fluorescence in situ hybridization positive colorectal carcinomas

Y. Fu*, X. Pu, X. Fan

*Department of Pathology, China

Background & objectives: To gain insight into the clinicopathologic profile of colorectal carcinomas harbouring oncogenic NTRK fusions based on eastern populations as well as make the best testing algorithm for the screen.

Methods: We use pan-Trk immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) respectively to screen NTRK fusions in a large, unselected cohort of 819 colon cancers, either IHC or FISH positive cases were further detected by next-generation sequencing (NGS).

Results: IHC staining was observed in ten cases, FISH positive was observed in 13 cases, total of 18 cases were under both a DNA-based and an RNA-based NGS assay. For clinicopathologic characteristics, besides MMR status (p=0.001), there is no difference between NTRK fusion-positive and negative cases. Nevertheless, classical fusion cases prefer to low differentiation (p=0.001) and different pattern of growth(p˂0.001). Besides, we found all five classical NTRK fusion cases and only one sub-classical case were harbouring MLH1/PMS2 deficiency. When combining FISH and MMR status, besides one sub-classical case, all five classical fusion were all detected, which means MLH1/PMS2 expression could further narrow classical fusions in FISH NTRK fusion positive cases.

Conclusion: Combine FISH and MLH1/PMS2 IHC would be a good testing algorithm for the screen effective NTRK fusions. Finally, if patients are going to undergo TRK-based targeted therapy only RNA-based NGS for detection of the specific fusion could tell the precise rearrangement information.

OFP-06-002

Human epidermal growth factor receptor 2 positivity in gallbladder carcinoma is associated with papillary structure and shows bidirectional prognostic value

L. Chen*, Y. Hou, J. Huang

*Zhongshan Hospital, China

Background & objectives: Gallbladder carcinoma (GBC) is associated with poor prognosis. HER2 is a promising therapeutic targe for GBC. The objective of this study is to explore HER2 status in a cohort of patients with GBC and its correlations with clinicopathological features.

Methods: High-output tissue microarrays were constructed for 306 cases of GBCs. HER2 expression was assessed using immunohistochemistry (IHC), and HER2 gene amplification was analysed using fluorescence in situ hybridization (FISH) in accordance with the up-to-date consensus for HER2 testing in gastric cancer. Correlations between HER2 status, clinicopathological parameters, and survival data were analysed.

Results: Of 306 GBC cases, 223 (72.9%) were adenocarcinomas, of which, 62 (27.8%) cases were papillary adenocarcinomas or had partial papillary structure. HER2 positivity was observed in 16.1% (36/223) of patients with adenocarcinomas. However, HER2 positivity was higher in adenocarcinomas with papillary structures (41.9%, 26/62, P < 0.001). Survival data were available for 143 radical resected primary gallbladder adenocarcinoma cases with 24 HER2-positive tumours; the five-year survival rate was 52.9%. In stage 0-II, the HER2-positive group had a similar prognosis to that of the HER2-negative group (P = 0.354). The HER2-positive group had a lower mortality rate in stage III (P = 0.005), but higher mortality in stage IV (P =0.005).

Conclusion: HER2 positivity was significantly higher in patients with gallbladder adenocarcinoma with a papillary structure. The prognostic value of HER2 was discordant among different clinical stage in GBC, showing no predication in the early stages, better in stage III, but worse in stage IV.

OFP-06-003

BRAF mutational testing practices in metastatic colorectal cancer

M. Hummel*, S. Hegewisch-Becker, J.H. Neumann, A. Vogel, K. Jöhrens

*Institute of Pathology, Charité - Universitätsmedizin, Berlin, Germany

Background & objectives: The metastatic colorectal cancer (mCRC) treatment landscape is rapidly evolving. Molecular testing is critical for guiding treatment decisions according to current guidelines. Determining BRAF mutation status is of diagnostic and therapeutic relevance. Many methods exist for BRAF mutational testing.

Methods: BRAF mutation testing practices in BEACON CRC study and BRAF ring trial (Quality Assurance in Pathology, QuIP) for mCRC 2020 were reviewed. We evaluated the methods used for BRAF status determination from 510 samples in BEACON CRC study, the largest Phase III trial in BRAFV600E-mutant mCRC. We evaluated real-world BRAF diagnostic testing practices in mCRC across 53 sites in Germany.

Results: In the BEACON CRC study, 50.5% of BRAF tests were performed alongside those for other gene alterations. Single gene detection was used in 48.8% of samples; IHC employing antibodies for detecting the mutated BRAF protein was used in 0.7% of samples. Discrepancies were observed between local and central testing, with confirmation of a locally detected BRAFV600E mutation in 90.7% of samples. Most discrepancies were due to insufficient neoplastic tissue in the sample. In the BRAF ring trial for mCRC, a broad range of methods for BRAF testing were used (NGS, PCR, IHC), with varying reliability. Molecular testing was the most reliable method (100% of positive tests vs 67% for IHC).

Conclusion: BRAF mutational testing is necessary in all patients with mCRC before initiation of first-line treatment. There are a large number of methods available for determining BRAF mutational status; however, the reliability of the tests vary. The BRAF ring trial for mCRC demonstrated the need for standardization of diagnostic procedures. Other tests are preferred over IHC for testing of genetic alterations in mCRC; the BRAF antibody IHC test may be useful for screening, however, molecular testing is the gold standard.

Funding: BEACON trial NCT02928224 sponsored by Pfizer and conducted with support from Merck KGaA, ONO Pharmaceutical, Pierre Fabre. BRAF ring trial funded by Pierre Fabre Germany.

OFP-06-004

Ex vivo sentinel lymph node mapping and one-step nucleic acid amplification (OSNA) for ultrastaging in gastric cancer

B. Märkl*, B. Grosser*, K. Bauer, D. Vlasenko, G. Schenkhirsch, A. Probst, B. Kriening

*Institute of Pathology and Molecular Diagnostics, University Hospital Augsburg, Germany

Background & objectives: One-step nucleic acid amplification (OSNA) is an established method for molecular lymph node (LN) staging by detecting cytokeratin 19 (CK19) mRNA. In this study, the effectiveness of OSNA with ex vivo SLN mapping is compared with conventional histology including immunohistochemistry.

Methods: LNs were retrieved from gastrectomy specimens in an unfixed state and after ex vivo SLN mapping using methylene-blue. LNs were sectioned to provide samples for histological investigation and OSNA. After fixation, further LNs were dissected to gain sufficient LN counts.

Results: In total, 334 LNs were retrieved in fresh state from 41 patients. SLN detection was successful in 29 out of 40 cases, with a correct LN status prediction in 23 cases (79%). The low ex vivo SLN detection rate resulted in an overall accuracy of only 58%. Excluding one case with failure likely caused by processing error, OSNA showed a high effectiveness with sensitivity, specificity, and accuracy rates of 85.4%, 93.5%, and 92.4%, respectively. The LN status could be predicted in all but one case, in which the single positive LN was not eligible for OSNA testing. OSNA evaluation led to upstaging from N0 to N+ in three cases (14%).

Conclusion: The ex vivo SLN protocol used resulted in a relatively poor detection rate. However, the OSNA method was not compromised by this detection rate and proved to be a safe method for LN staging in gastric cancer. The OSNA method has the potential to surpass conventional techniques.

OFP-06-005

Predictive value of NLR, TILs (CD4+/CD8+) and PD-L1 expression for prognosis and response to neoadjuvant chemotherapy (NAD-CT) in locally advanced Gastric Cancer (LAGC)

M. Martini*, I.V. Zurlo, A. Strippoli, A. Cocomazzi, G. Tortora, E. Bria, M. Basso

*Fondazione Policlinico Universitario A. Gemelli, IRCCS, UCSC, Italy

Background & objectives: The combination of perioperative chemotherapy plus complete surgical resection is currently accounted as the first-choice strategy in patients with LAGC. Nevertheless, the partial response rate makes it necessary to search parameters to select patients who would benefit most from NAD-CT.

Methods: We performed a retrospective analysis on a cohort of 65 LAGC cases, EBV negative and without MMR defect, submitted to NAD-CT plus surgical resection. We evaluated the neutrophil-lymphocytes ratio (NLR) in peripheral blood (before and after treatment) and the TILs density (CD4/CD8 tissue ratio) and PD-L1 expression by immunohistochemistry (IHC) on bioptic tissues before the treatment.

Results: Our results were correlated with the biological features, histological response (TRG) and clinical outcome (PFS and OS). We found that NLR, TILs and PD-L1 expression showed a significant correlation with TNM stage, lymphovascular invasion and response to NAD-CT (TRG). Correlating the NLR, TILs and PD-L1 expression with PFS and OS, we found that patients with lower NLR levels (<2.5 ratio), lower TILs (<0.2 ratio) and higher PD-L1 level (CPS≥1) had a significantly better PFS and OS than those with higher NLR, higher TILs and lower PDL1 expression (p<0.0001). Multivariate and multiple regression analyses confirmed the predictive and prognostic role of all three parameters, especially when all three parameters are combined.

Conclusion: Our study demonstrated that pre-treatment NLR, TILs and PD-L1 expression, are predictive and prognostic parameters in NAD-CT treated LAGC suggesting a pivotal role of the systemic and tumour microenvironment (TME) immunological profile in the response to chemotherapy.

Funding: Università Cattolica del Sacro Cuore (Linea D1 2017, 2018) for Dr. Maurizio Martini

OFP-06-006

Immunohistochemical expression of autophagy-related proteins in HER2 positive gastric carcinomas

A. Ieni*, C. Pizzimenti, G. Giuffrè, R.A. Caruso, G. Tuccari

*Department of Human Pathology in Adult and Developmental Age “Gaetano Barresi”, Section of Pathology, University of Messina, Italy

Background & objectives: Autophagic related proteins (ATGs) have been analysed in differentiation and cancer progression. The aim of the present study is to investigate a cohort of gastric carcinomas (GC) by five ATGs antisera evaluating their possible relationship with final outcome of patients.

Methods: 123 GCs has been studied by ATG antisera utilizing Masuda's criteria that define positive cases those in which at least two out of five protein expressions were documented. Sensitivity, specificity and efficiency (expressed as a result in percentage of what could be ideally expected, hence with 100% as ideal case) of each immunohistochemical expression of autophagy-related-proteins have been evaluated.

Results: The immunohistochemical signature for autophagy (A-IHC) was 49.59% as whole. The percentage of A-IHC ranged from 31% for poorly cohesive carcinomas to 56% for adenocarcinomas. High values for sensitivity, specificity and efficiency were recorded relatively to LC3A/B, Beclin-1 and p62. In univariate analysis of GC, grade, stage, Ki67 expression, HER2 status as well as A-IHC appeared as prognostic significant parameters with a high p-value (p < 0.001). Finally, in multivariate analysis HER2 status, stage and A-IHC emerged as independent prognostic variables. In the comparison of survival curves, GC cases immunoreactive for A-IHC exhibited a shorter survival with a worse outcome.

Conclusion: A-IHC could represents an additional morphological tool to provide prognostic elements in order to identify patients affected by aggressive with shorter survival and worse outcome.

OFP-06-007

Prognostic significance of the lymph node ratio in stage III colorectal adenocarcinoma

A.F. Beirat, J.Z. Amarin, H.H. Suradi, Y.Z. Qwaider, M. Al-Hussaini*

*King Hussein Cancer Center, Jordan

Background & objectives: The lymph node ratio (LNR) may offer superior prognostic stratification in colorectal adenocarcinoma compared with the N stage. However, candidate cut-off ratios require validation. Our aim was to study the prognostic significance of LNR at a cut-off ratio of 0.10.

Methods: We reviewed the pathology records of all patients with stage III colorectal adenocarcinoma who were managed at the King Hussein Cancer Center between January 2014 and December 2019. We then studied the clinical characteristics of the patients, correlates of the lymph node count, prognostic significance of positive lymph nodes, and value of sampling additional lymph nodes.

Results: We included 226 patients. The number of lymph nodes sampled was < 12 in 13 cases (5.8%) and ≥ 12 in 213 (94.2%). The median number of lymph nodes sampled varied according to tumour site, neoadjuvant therapy, and the pathologist’s level of training. According to the TNM system, 142 cases were N1 (62.8%) and 84 were N2 (37.2%). The LNR was < 0.10 in 98 cases (43.4%) and ≥ 0.10 in 128 (56.6%). Survival distributions differed according to LNR (p = 0.022) but not N stage (p = 0.065). In adjusted analyses, both N stage and LNR predicted overall survival (p = 0.044 and p = 0.010, respectively).

Conclusion: The LNR is a robust predictor of overall survival in patients with stage III colorectal adenocarcinoma. At a cut-off ratio of 0.10, the LNR offers better prognostic stratification compared with the N stage and is less susceptible to variation introduced by the number of lymph nodes sampled, which is influenced by both clinical characteristics and grossing technique.

OFP-06-008

Inter-laboratory variation in the assessment of lymphovascular invasion in T1 colorectal cancer in the Netherlands

L. van der Schee*, A. Verbeeck, I.A. Deckers, C.C. Kuijpers, G.J.A. Offerhaus, T.C. Seerden, F.P. Vleggaar, P.J. van Diest, L.M. Moons, P. Snaebjornsson, M.M. Laclé

*Department of Pathology, University Medical Center Utrecht, The Netherlands

Background & objectives: Lymphovascular invasion (LVI) is a risk factor for lymph node metastasis in T1 colorectal cancer (CRC). When LVI is present in the local resection, complementary surgery needs consideration. We aimed to study the inter-laboratory variation in the assessment of LVI.

Methods: All synoptic pathology reports of locally resected T1 CRCs between 2015 and 2019 were retrieved from the Dutch Pathology Registry (PALGA). Absolute proportions of LVI per laboratory were determined and compared between the laboratories. Multivariable logistic regression was performed to adjust for case mix. Additionally, a questionnaire about assessment methods and criteria for LVI was circulated among 50 pathologists.

Results: In total, 5917 T1 CRCs from 35 laboratories were included. Of these T1 CRCs, 18.3% were reported to have LVI (range 7.1% - 43.5%). After adjustment for case mix, still 37% of laboratories (n=13) reported a proportion of LVI outside the 95% confidence interval limits of the overall national proportion. In a subgroup of 3459 patients where LVI would have been the decisive factor for additional surgery (i.e., patients without other high-risk factors), case-mix adjusted proportions of LVI varied between the laboratories by a factor of nine (range 4.6% – 41.7%). The questionnaire showed considerable differences between pathologists in definitions and methods used to assess LVI.

Conclusion: The results of this nationwide study show that substantial inter-laboratory variation in the assessment of LVI in T1 CRC exists, independent of case mix. This variation might be partly explained by differences in assessment methods and criteria, suggested by the results of our questionnaire. This underlines the importance of standardization of the assessment of LVI, because the observed variation may lead to unwanted differences in treatment of patients with T1 CRC.

OFP-06-009

Shrinkage versus fragmentation response in neoadjuvant treated oesophageal adenocarcinoma: significant prognostic relevance

C. Graham Martínez*, S. Kus Öztürk, A. Al-Kaabi, J. Bokhorst, C. Rosman, H. Rütten, C. Wauters, P. Siersema, I. Nagtegaal, C. van der Post

*Radboud University Medical centre, The Netherlands

Background & objectives: No consensus exists on different tumour regression grading (TRG) systems for therapy effects of neoadjuvant chemoradiotherapy (nCRT) in oesophageal adenocarcinoma. The aim is to identify tumour regression patterns of oesophageal adenocarcinoma in response to nCRT, and their association with survival.

Methods: Patients with a potentially curable oesophageal adenocarcinoma (cT1-4N0-3M0) who achieved partial response to nCRT combined with surgery in the period 2005–2018 were included. Two representative H&E slides of the surgical specimen were selected per case for histomorphologic assessment of the regression pattern. Scoring of regression patterns was performed by two observers according to a pre-defined three-step flowchart.

Results: In total, 110 cases were included. Histopathology review showed two major regression patterns: fragmentation (60%) and shrinkage (40%). There was an excellent interobserver agreement using the flowchart (κ=0.87). Compared to patients with a shrinkage pattern, patients with a fragmented regression pattern had a significantly higher pathological stage (stage III/IV: 52% vs 16%; p<0.001), less downstaging (48% vs 91%; p<0.001), higher residual tumour cells in the muscularis (88% vs 32%; p<0.001) and subserosa (67% vs 16%; p<0.001), and a higher risk of disease recurrence (RR 2.83, 95% CI 1.5-5.5). Patients with a shrinkage pattern had a better overall survival compared to patients with a fragmentation pattern (5-years: 80% vs 30%, p=0.002).

Conclusion: We established a reproducible classification of tumour response that was associated with downstaging and better prediction of patient outcome.

Funding: This work was supported by an Alpe d'HuZes/KWF program grant (KWF UL 2013-6311)].

OFP-06-010

The prediction model for gastric cancer development based on gastritis assessment and miR-21 expression

A. Shimanskaya, S. Mozgovoi*, V. Rubtsov, E. Pomorgaylo, A. Kononov

*Omsk State Medical University, Russia

Background & objectives: The accuracy of gastric cancer risk evaluation can be increased by joint assessment of gastritis parameters, including corpus-predominant gastritis index (CGI), gastritis OLGA staging and miR-21 expression with gastric cancer risk stratification.

Methods: All parameters were assessed in 62 cases of chronic gastritis (CG) and 60 resected gastric samples (adenocarcinoma). Samples localization in both group corresponded to the OLGA staging protocol. miR-21 expression was evaluated by qRT-PCR, normalized to RNU6B. Multiple logistic regression was used for predictive potential assessment and nomogram construction.

Results: Predictor variables showed significant positive association with gastric cancer: OLGA stage (OR = 8.07, CI [1.52-42.85]; p= 0.013), CGI (OR = 11.77, CI [2.59-53.6]; p= 0.001) and miR-21 expression (OR= 13.56, CI [4.6-40.04]; p 0.000002). Parameters after model accuracy estimation were as follows: -2 Log likelihood - 58,3, criterion χ2 - 110,84 (p=0.00001), ROC curve AUC - 0.97, sensitivity 93%, specificity 90%. The constructed nomogram indicates gastric cancer risk by connection the value of OLGA stage (right axis) with the expression level of miR-21 (left axis) and tailored to the CGI value. Indication and stratification of gastric cancer risk based on the result value.

Conclusion: The predictive statistical model and the nomogram based on previously defined parameters allows to perform stratified assessment of gastric cancer risk with having high validity. This approach can be used in organizing strategies for secondary prevention of gastric cancer.

OFP-06-011

HER2 assessment for differential diagnosis in gastric precancerous lesions

S. Mozgovoi*, M. Keruchenko, A. Shimanskaya, S. Glatko, D. Lining, A. Kononov

*Omsk State Medical University, Russia

Background & objectives: Amplification of HER2 is suitable not only for gastric cancer, but for precancerous changes also. The aim of the study was to reveal the usefulness and patterns of HER2 protein and gene expression on the spectrum of carcinogenesis.

Methods: Gastric biopsy samples (n=111) were included in the study: atrophic gastritis (26), uncertain/indefinite dysplasia (21); intestinal type adenomas and non polipoid lesions with low-grade dysplasia (18) and high-grade dysplasia (23); early invasive adenocarcinoma (23). Serial sections of tissues were used for routine examination, HER2 immunohistochemistry and silver-enhanced in situ hybridization (SISH) with adapted manual tissue microarray technique.

Results: Overexpression of HER2 (2+ and 3+) with the presence of a membrane or basolateral immunohistochemical pattern were found in 14 cases: 5 among invasive carcinoma group with SISH confirmation of all 2+/3+ positive cases, 1 in indefinite, 3 in high grade dysplasia and 2 in low grade. The presence of non-conventional staining variants of HER2 expression were revealed in 52 cases: apical label (the apical edge of the cell), cytoplasmic (diffuse staining of cell cytoplasm), “strip form” (focal cytoplasmic staining of the cell, forming a strip) and nuclear staining. There were no statistically significant differences in the expression of HER2 between different categories of dysplasia and invasive adenocarcinoma (p<0,05).

Conclusion: We did not reveal the presence of classical significant HER2 overexpression during early precancerous changes. Non-conventional HER2-staining needs more data and additional analysis for practical interpretation and realisation of appropriate follow up strategy. These results defined the possibility of using this marker for differential diagnostics in the situations of small volume or low informative biopsy material according to its high specificity.

OFP-06-012

Identification of Epstein-Barr virus-encoded small RNAs (EBER) in gastric adenocarcinomas

I. Mikhailov*, N. Danilova, N. Oleynikova, A. Chayka, V. Khomyakov, P. Malkov

*Department of Pathology, Medical Research and Educational Center, Lomonosov Moscow State University, Russia

Background & objectives: Gastric adenocarcinoma associated with the Epstein-Barr virus is a separate molecular subtype of gastric cancer with a characteristic set of genetic disorders and clinical and morphological features. In this study we performed EBER identification in patients from the Russian Federation.

Methods: We used samples of surgical material from 233 patients from Russian Federation with a verified gastric cancer. EBER chromogenic hybridization in situ (EBER-CISH) was performed in each case. The results of EBER identification were compared with the main clinical and morphological characteristics of gastric cancer.

Results: A total of 18 EBER-positive gastric adenocarcinomas and 215 negative cases were identified using EBER-CISH. The frequency of occurrence (incidence) was 7.73%. As in other described patient populations the identified EBV-associated gastric adenocarcinomas were characterized by a less aggressive phenotype. EBER identification in gastric adenocarcinomas was statistically significantly associated with the absence of distant metastases (p=0.047). Among all 18 identified cases of EBV-associated adenocarcinomas there were no cases with distant metastases and, accordingly, IV stage tumours. There were no statistically significant differences for other TNM clinical stages. This fact can be explained by the significant dominance of 106 cases of III stage tumours in our sample.

Conclusion: It is known that the prevalence of EBV-associated gastric adenocarcinoma differs depending on the population. The results obtained showed that the incidence of EBV-associated gastric adenocarcinoma in the studied sample of cases from Russian Federation is 1.27% lower than the world average of 9%.

Funding: This work was supported by Russian Science Foundation (RSF) grant number 20-75-00037.

OFP-06-013

Immunohistochemical markers as additional criteria for evaluation of efficacy of GERD-related therapy

S. Mozgovoi*, I. Lapteva, I. Matoshina, M. Livzan

*Omsk State Medical University, Russia

Background & objectives: Pathogenesis of gastroesophageal reflux disease (GERD) has close association with intercellular contacts and appropriate level of epithelial proliferation. The aim was to determine the potential of histopathological changes and IHC markers for assessment of the effectiveness of GERD treatment.

Methods: 23 patients with GERD-related symptoms and endoscopic signs and 15 patients as controls were included. Standard proton pump inhibitor (control group) and in combination with chondroitin sulfate and hyaluronic acid on a bioadhesive carrier (study group) were used. Mucosal biopsies from distal esophagus were taken for analysis by histopathology and claudin-1, claudin-4 and Ki-67 expression assessment by immunohistochemistry.

Results: GERD-specific alterations in the esophageal mucosa were confirmed. Regression of clinical, endoscopic, and histopathological parameters was noted in both groups after 4 weeks from the onset of treatment (p < 0,05). In both groups expression levels of claudun-1 and claudin-4 were statistically higher after therapy (p < 0,05). Migration of claudin-1 expression towards the upper layers of esophageal mucosa was revealed also. The Ki-67 level was lower after treatment, especially at the margins of the erosions (p < 0,05). The expression levels of both claudins did not correlate with clinical features and had a weak correlation with histopathological parameters including dilated intercellular spaces.

Conclusion: The absence of significant differences between treatment options concerning reverse development of morphological parameters were established. Taken together, the expression of tight junction-related component (claudins) and Ki-67 can be used as additional criteria for evaluation of efficacy of GERD therapy.

OFP-06-014

Assessment of the density of the population of cancer-associated fibroblasts near the tumour budding in colorectal cancer

N. Oleynikova, I. Mikhailov*, P. Malkov, N. Danilova

*Department of Pathology, Medical Research and Educational Center, Lomonosov Moscow State University, Russia

Background & objectives: Cancer-associated fibroblasts (CAF) are cells with mesenchymal properties located in the tumour stroma. One of CAF`s marker is podoplanin (POD). Tumour budding (single cells are located in the invasive edge of the tumour) is an independent prognostic factor.

Methods: We used Double Stain IHC Kit: M&R on human tissue (ab210058) with antibodies PCK (Dako, to identify buds) and POD (Abcam, as CAF marker) in 43 colorectal cancer. POD expression was evaluated by quantitative method (by color separation and half-counting of the area in the field of view in the LAS X program) in invasive region and around buds.

Results: The aim was assessment of the density of CAF near the buds. POD around bud was negative in 30,4%, weak in 21,7%, moderate in 30,4% and significant (17,4%). A statistically significant relationship (p<0.01) was found between the level of POD around the tumour budding and its level in the invasive region. No significant differences in the density of CAF depending on the presence of the mucinous component, detected by the c2method(p=0.98). In most mucinous adenocarcinomas, a significant POD reaction was observed directly around the mucinous complexes and mucus lakes (p=0,85). We detected a relationship (p=0,023) between presence of buds and depth of tumour invasion(T), and on the presence of metastases(N).

Conclusion: Using the duplex stain technology, the expression of POD around tumour budding was demonstrated for the first time, which allows us to judge the density of CAF. It was shown that the density of the POD expression around the tumour budding significantly corresponds to the reaction in the invasive region, which indicates that there is no need to evaluate it specifically around the tumour buds. For the first time, we described a more significant reaction near mucinous complexes.

OFP-06-015

Lymph node molecular analysis of colorectal carcinoma in situ

M.T. Rodrigo Calvo*, S. Lopez-Prades, K. Saez De Gordoa, A. Diaz Lorca, I. Archilla, E. Ortiz, P. Alonso, S. Lahoz, M. Cuatrecasas

*Hospital del Clínic, Spain

Background & objectives: Colorectal carcinoma in situ (pTis) is considered to have little or no risk of lymph node (LN) metastasis. However, lymphatic vessels proliferate in the lamina propria through a process of "aberrant lymphangiogenesis". We aimed at characterizing pTis LNs with OSNA.

Methods: In this observational and retrospective study, LNs from pTis CRC surgical specimens were freshly dissected. Part of the LN was used for conventional histological stage with H&E (pN) and the rest used for analysis with the OSNA (One Step Nucleic Acid Amplification) molecular assay, based on RT-LAMP PCR, for amplification of CK19 mRNA.

Results: LNs from 39 CRC pTis were analysed by H&E and OSNA. Mean age was 68.6 years-old, 59% (23) men, 41% (16) women; 56% (22) were right-sided, 23% (9) transverse, 15% (6) left-sided, and 6% (2) rectal. All carcinomas were low grade. All cases were pN0 by H&E. OSNA was positive in 11 (28%) cases, with a total tumour load (TTL), defined by the amount of CK19 mRNA copies/μL in all LN of a given case, was between 400 and 4270 copies/μL. No patient received adjuvant therapy. All patients are alive without disease at 1 to 5 years follow-up.

Conclusion: We demonstrate the presence of tumour cells in regional lymph nodes in exceedingly early stages of the disease, detected only by molecular methods. We corroborate our previous observations of the prognostic value of the amount of tumour burden in LNs, demonstrating that TTL values <6000 copies/μL are not associated to risk of recurrence.

OFP-06-016

Entire Lymph Node Molecular Analysis (ELNMA) of colorectal carcinoma. Correlation with pN staging using immunostained cytology smears. A multicentre study

S. Lopez-Prades*, M.T. Rodrigo Calvo, K. Saez De Gordoa, Á. Romo Navarro, I. Archilla, J. Ruiz Martín, J. Tarragona, S. Lahoz, M. Cuatrecasas

*Hospital Clinic, Spain

Background & objectives: All lymph node (LN) molecular staging studies using OSNA from colorectal cancer (CRC) have used half LN obtaining 15-50% overstaging. We aimed at analysing the entire LN with OSNA as well as providing the pN staging with cytological smears.

Methods: This ongoing multicenter and prospective ELNMA (Entire Lymph Node Molecular Analysis) study includes non-metastatic CRC patients without neoadjuvant treatment. LNs are freshly dissected, cut in half and cytological smears are performed. Then, the whole LN is processed with the OSNA assay. Each slide contains smears from 6 LNs, which are stained with cytokeratin 19 (CK19) immunocytochemistry for pN staging.

Results: We analysed 980 fresh LNs from 53 patients (mean 18 LN/patient); 57% (30) men, with a mean age of 71.36 years. By cytology, 81% (43) cases were pN0, 15% (8) pN1a+b, and 4% (2) pN2a+b. The concordance between OSNA and cytology was 96% (51). All OSNA negative cases (41; 77%) were negative by cytology, and two presented isolated tumour cells (ITC) on cytology smears, pN0(i+). OSNA positive cases (12; 23%) had total tumour loads (TTL, amount of CK19 mRNA in all LNs/patient) of 410 to 88.000 copies/μL, with 83% (10) concordance with the cytology. The remaining 2 cases were pN0 by cytology, with TTL of 410 and 5800 copies.

Conclusion: LN cytology smears stained with CK19 immunocytochemistry allows performing the pN stage based on the number of positive LNs and enables to use the entire LN for the OSNA assay, with 96% concordance. LN molecular analysis identifies 4% (2) of patients who were pN0 by morphological methods. Although preliminary, these results show the utility of molecular LN staging, which could be used for stage II CRC, where conventional H&E pN staging is less sensitive for the detection of micrometastasis.

OFP-06-017

pT1 CRC patients at risk of recurrence are identified with lymph node molecular analysis. A multicentre study

K. Saez De Gordoa*, M. Rodrigo-Calvo, I. Archilla, S. Lopez-Prades, A. Diaz Lorca, J. Tarragona, I. Machado, J. Ruiz Martín, S. Lahoz, D. Zaffalon, M. Pellisé, M. Cuatrecasas

*Pathology Department, Hospital Clínic, Barcelona, Spain

Background & objectives: A high percentage of early colorectal carcinomas (pT1) undergo surgery, with no clear impact on survival. Molecular analysis of lymph nodes of pT1 surgical resections was performed in order to identify cases at risk of recurrence to optimize patient’s management.

Methods: In this multicentre retrospective study we analysed the lymph nodes (LN) from pT1 CRC surgical specimens treated either primary by endoscopic resection or by surgery using the OSNA (One Step Nucleic Acid Amplification) assay, which detects mRNA from CK19. LNs were freshly dissected, using half for the OSNA assay and the other half for H&E analysis.

Results: Eighty-nine pT1 CRCs were included, 50 treated with endoscopy followed by surgery and 39 treated primarily with surgery. Mean age 62.6 years, 55% male, 49% in the left colon, 37% right, and 14% rectal. 22 cases (25%) had positive LNs with OSNA, 5 of them also with H&E. The total tumour load (amount of CK19 mRNA in all LNs of a patient) was low, but for 3 cases with ≥6000 copies. LNs were positive with H&E in 9% (n=8), two of them were negative by OSNA. At follow-up (5 months to 8 years), 82 patients are alive without disease, 3 died of other causes, and 4 were lost to follow-up.

Conclusion: We detected 25% lymph node positivity with the OSNA assay, 16% more than with H&E. The total tumour loads (TTL) were low in all patients except in 3 cases with TTL > 6000 copies/μL, which is associated with a higher risk of recurrence and worse survival according to previous studies. These patients would be candidates for closer follow-up. Molecular LN analysis from early CRC provides more information than H&E about the real nodal status and could help in patient’s management.

OFP-06-018

The relationship of clinicopathological features and the Ki67 proliferation index with prognosis in colorectal carcinomas

T. Kebat, G. Dal*, M. Yıldırım, A. Argon

*Izmir Bozyaka Training Research Hospital, Pathology Department, Turkey

Background & objectives: Colorectal cancers are very common. Many histopathological and molecular features that can be used to predict the prognosis. It was aimed to investigate the prognostic significance of the histopathological features and the immunohistochemical Ki67 proliferation index in colorectal cancers.

Methods: A total of 196 patients who underwent resection for colorectal adenocarcinoma in one centre from 2006 to 2012 were included in this study. All of the cases were evaluated in terms of age, sex, localization, tumour size, growth pattern, histological grade, LVI and PNI, surgical margin positivity, pT, pN, stage, recurrence, metastasis, site of metastasis and immunohistochemical Ki67 proliferation index.

Results: In statistical analysis, female gender, polypoid growth pattern, medullary histological type, absence of lymphovascular and perineural invasion, negative surgical margin, low pN grade and no metastasis were found to be associated with long disease-free and overall survival time. Although high Ki67 proliferation index was associated with poor differentiation and surgical margin positivity, it was not associated with disease-free survival (DFS) and overall survival (OS).

Conclusion: The results of our study show that the Ki67 proliferation index is not more important in predicting DFS and OS than histological features. Our study has a feature to shed light on the literature in terms of being a study in which many histopathological features were evaluated in a large series. However, it should not be forgotten that the search for new target molecules that will predict the behaviour of tumours and prevent the progression of the tumour continues.

OFP-06-019

Incidental primary tumours of the appendix: analysis of 4047 appendectomy specimens in a 15-year retrospective study

C. Alves-Vale*, M. Brito Pereira, F. Tortosa, P. Borralho

*Pathology Department, CUF Descobertas Hospital, Lisbon, Portugal

Background & objectives: Acute inflammation is the most frequent finding in appendectomy specimens. Nonetheless, it is well known that tumours may be incidentally found. The main goal of this study was to characterise the primary tumours diagnosed in appendectomies performed in our institution.

Methods: A retrospective review was conducted for all appendectomies received in our department between January 2006 and December 2020. Patients with clinical and radiological suspicion for neoplasm were excluded. Reports with incidental histopathological diagnosis of neoplasm were further analysed, and nomenclature was updated according to the 5th edition of WHO Classification of Tumours (Digestive System).

Results: A total of 4047 surgical specimens were retrieved. Appendiceal tumours were found in 73 cases (overall incidence of 1,80%), including appendectomies performed for acute appendicitis or at staging procedures for extra-appendiceal malignancies. The median age was 52 years (range 14-95), without age predilection (M/F ratio =1,03). Neuroendocrine tumours were the most frequent entity (n=29, comprising 39,72% of all incidental findings). Additional diagnoses include low-grade mucinous neoplasm (n=17), high-grade mucinous neoplasm (n=1), adenocarcinoma (n=8, comprising 3 goblet cell adenocarcinomas, 3 adenocarcinomas NOS and 2 mucinous adenocarcinomas), and diffuse large B-cell lymphoma (n=1, initial presentation). Sessile serrated lesions (n=15, low-grade dysplasia in 4) and hyperplastic polyps (n=2) were also described.

Conclusion: Incidental primary tumours of the appendix are rare. Our incidence correlates with that described in the literature. These neoplasms may be diagnosed in different clinical settings, isolated or in combination with additional histopathological processes. Therefore, careful macroscopic and microscopic examination should be performed in all appendectomy specimens, independently of the preoperative diagnosis.

OFP-06-020

RAS and BRAF mutational study in synchronous colorectal cancer

B. Sepodes*, J. Gama, A. Gomes, P. Teixeira, Â. Jesus, G. Fontinha, J. Madeira, F. Ramalhosa, C. Faria, M.B. Pimentão, V. Almeida, R. Oliveira Caetano, M.A. Cipriano

*CHUC, Portugal

Background & objectives: Colon cancer comprises molecular alterations that guide treatment in advanced stages. Regarding synchronous tumours, there is no consensus about testing all or only the advanced CRC. We aim to assess mutational concordance in synchronous CRC.

Methods: In the last two years, at our institution, eight patients, aged between 44 and 79 year-old with synchronous CRC were tested for KRAS and BRAF mutations. Clinical and pathological data was retrieved from the hospital database. The local ethical committee (CHUC 137-20) approved this study.

Results: Seven patients presented two synchronous tumours, in which three had mutational concordance: one was wild-type for KRAS/BRAF, other had the same mutation in KRAS (p.Gly12Asp) and the remaining one was wild-type for KRAS, having both neoplasms BRAF V600E mutation.

The group composed of four patients with mutation discrepancy only had KRAS mutation in one tumour: two patients with pGly13Asp mutation, one patient had p.Gly12Asp and p.Gin61Arg and the last one p.Gly12Val.

The youngest patient presented a three synchronous tumours with mutational discordancy: two had NRAS mutation and the other KRAS mutation.

Conclusion: Synchronous colorectal neoplasias seem to exhibit a different gene mutational signature. As the treatment approach is tailored according to this information, as such, it is crucial to test all tumours in synchronous cases.

OFP-06-021

Sessile serrated lesions (SSL) of the colon and their way towards malignancy - immunohistochemical features

D. Raduta*, S. Zurac, C. Socoliuc, B. Mateescu, A. Bengus, M. Filip, R. Ardeleanu, A. Cernat, C. Popp

*Colentina Clinical Hospital, Romania

Background & objectives: Serrated neoplasia pathway leads to approximately 30% of all colorectal carcinomas.

The aim of this study was to evaluate MLH1, BRAF and p53 status by immunohistochemistry in sessile serrated lesions and to identify molecular alterations as steps towards malignancy.

Methods: We designated a retrospective case control study, including 11 sessile serrated lesions with dysplasia. For each patient with dysplasia we included a non-dysplasia patient matching sex and age.

Immunostaining of MLH1, BRAF and p53 was done on all 22 cases and we evaluated the percent of nuclear loss of MLH1, cytoplasmic positivity of BRAF and nuclear positivity of p53.

Results: Fourteen patients had microsatellite instability with surprisingly higher nuclear loss of MLH1 in non-dysplastic crypts (65%), comparative to the rate found in those dysplastic (55%).

p53 mutation was noticed in 9 lesions, mostly dysplastic with a double nuclear positive rate (30%) compared to only 15% in non-dysplastic crypts. One third of p53 mutated SSL are microsatellite stable (MSS), all of them with dysplasia.

Half of the SSL with intense cytoplasmic positivity of BRAF were also p53 positive, almost all cases being dysplastic.

Almost 1/3 of cases were MSS (5 non-dysplastic and 3 dysplastic) with BRAF cytoplasmic positivity in 70% of the cells in dysplastic crypts and 54% in non-dysplastic.

Conclusion: Our results suggest that loss of MLH1 expression in non-dysplastic crypts in SSL could precedes the development of MLH1-deficient dysplasia and further to adenocarcinoma. SSL with microsatellite stability, but BRAF mutated, has poor prognostic. p53 mutation is common in MSS/BRAF mutant SSL.

Including immunohistochemical evaluation of BRAF V600E and Tp53 mutation and loss of MLH1 expression may be the key to identify sessile serrated lesions with higher potential to progression into carcinoma.

OFP-06-022

Density of CD8+ infiltration in the peritumoral mucosa in gastric cancer is significantly associated with lymphovascular invasion

I. Mikhailov*, N. Danilova, N. Oleynikova, P. Malkov

*Department of Pathology, Medical Research and Educational Center, Lomonosov Moscow State University, Russia

Background & objectives: The immune microenvironment of peritumoral tissues is an important trend in gastric cancer research, as immune cells in peritumoral tissues probably take part in epithelial-mesenchymal transition, metastasis and other processes of tumour progression.

Methods: We used samples of surgical material from 134 patients with a verified gastric cancer. Immunostaining for CD8 (clone C8/144B) were performed in each case. The immunostaining results were evaluated using an automatic LASX morphometric analysis system. The results of the morphometric analysis are presented as the average area of the selected colour range objects in three fields of view.

Results: By conducting morphometric analysis it was found that the average area of CD8+ cells in the peritumoral mucosa in tumours with lymphovascular invasion is 6598.01 sq. microns, and in tumours without areas of lymphovascular invasion the average area of CD8+ cells is 4012.45 sq. microns. This difference is characterized by a high statistical significance p=0.0085. But when we assessed the density of CD8+ cell infiltration in the centre of the tumour tissue there were no significant differences in lymphovascular invasion.

Conclusion: Our results indicate that the presence of a high density of CD8+ infiltration of the peritumoral mucosa in gastric cancer may be an indirect sign of the presence of lymphovascular invasion. This fact also indicates a possible significant role of inflammatory infiltrate cells in the peritumoral mucosa for accelerating the processes of invasion and metastasis.

OFP-06-023

SOX9 mutation correlates with good prognosis and immune infiltration in stage II colon cancer

I. Archilla*, M. Cuatrecasas, S. Lahoz, C. Parra, A. Mas, J. Camps

*Pathology Department, Hospital Clínic, Barcelona, Spain

Background & objectives: The identification of molecular biomarkers is essential for a better therapeutic management of early-stage colon cancer (CC) patients. This study aims to characterize SOX9 mutational status, immunohistochemical (IHC) expression and its association with recurrence in stage II CC.

Methods: 84 chemotherapy-naive stage II CC were included. Tissue microarrays comprising normal mucosa, bulk of the tumour and invasive front were constructed for 71 cases and stained with SOX9 and CD8 antibodies. The remaining cases were whole-sectioned and stained with CD8. DNA-sequencing was performed in 44 cases using a panel of 48 CC-related genes that included SOX9.

Results: SOX9 was overexpressed by IHC in both SOX9 mutated and wild-type CC when compared to colonic mucosa (P<0.001), being higher when SOX9 was mutated (P<0.001). Recurrent cases showed higher SOX9 IHC expression in the bulk of the tumour (P=0.023) but not in the invasive front. DNA-sequencing revealed SOX9 mutation in 8 cases, of whom only 1 showed disease recurrence (P=0.046). Consistently, SOX9 mutations were associated with longer overall survival (P=0.029) in a validation cohort of 1095 colorectal cancers from the MSK-IMPACT. SOX9 mutated tumours showed higher CD8 lymphocytic infiltration analysed by IHC. Likewise, colorectal tumours from the TCGA (N=449) harbouring SOX9 mutations exhibited increased expression-based ImmunophenoScores compared to wild-types (P=0.016)

Conclusion: SOX9 is overexpressed by IHC in stage II CC and it is associated with the presence of gene mutation. SOX9 mutated tumours exhibit higher levels of cytotoxic lymphocytes and less frequency of recurrence, which highlights the potential value of SOX9 as a biomarker of relapse-free in early-stage CC.

OFP-06-024

"The imitation game" in mucosal prolapse syndrome: many faces of one clinical entity

Z. Gahramanli*, C. Cansiz Ersoz, S. Ersoz, B. Savaş, A. Ensari

*Ankara University School of Medicine, Turkey

Background & objectives: Mucosal prolapse syndrome (MPS) is an umbrella term for rectal mucosal disorders comprising solitary rectal ulcer syndrome (SRUS), proctitis cystica profunda, inflammatory cloacogenic polyp, and inflammatory cap polyposis. Histopathological features of MPS causing resemblance with other disorders including neoplasias were reviewed.

Methods: In this study, the medical records of 100 patients based on endoscopic, clinical and histological findings were reviewed retrospectively between 2015-2020. Histopathological features including fibromuscular obliteration, angulated crypts, serrated epithelial change (SEC), surface ulceration, muscularis mucosa thickening, mucin lakes and vascular changes were evaluated by an experienced team, while resemblance with other disorders was determined by a junior pathologist.

Results: Gender distribution was approximately equal (48% males, 52% females) with a median age of 54 years. The most common symptom was abdominal pain and constipation (61%), followed by rectal bleeding (16%) and weight loss (%6). Endoscopically only 40% of cases showed ulceration which correlated with histopathology (41%). Fibromuscular obliteration and crypt distortion were seen in almost all cases (%99 and %98%, respectively) while angulated crypts were noted in 92%, and SEC in 93% of cases. Majority of the cases (57%) showed resemblance with serrated polyps (43% hyperplastic polyps, 14% SSL) while 43% had the potential to be mistaken for an adenoma (27%) or dysplasia and/or neoplasia (15%).

Conclusion: The results of the study suggest that not all MPS cases have an ulcerated or polypoid appearance endoscopically. However, histopathologic features including complex crypt architecture, SEC, regeneration, acellular mucin may imitate polyps and/or neoplasia. Therefore, pathologists should be aware of the “imitation game” this entity likes to play before making an erroneous diagnosis. This is particularly true for untrained eyes who are likely to have difficulties at recognizing this benign entity.

OFP-06-025

Congenital enteropathies: a multidisciplinary approach for diagnosis

E.N. Kozan*, C. Tuna Kirsaclıoglu, Z. Kuloglu, B. Savaş, A. Kansu Tanca, A. Ensari

*Ankara University, Turkey

Background & objectives: Congenital enteropathies constitute a heterogeneous cluster of disorders that are rare, typically presenting with severe diarrhea in infancy. A detailed clinicopathologic documentation of rare congenital enteropathies with special emphasis on the role of pathologist in the diagnostic team is presented.

Methods: Clinical, histopathological, and genetic characteristics of 27 cases of congenital enteropathy comprising microvillus inclusion disease, abetalipoproteinemia, chylomicron retention disease, primary immunodeficiency, early onset IBD, DGAT1 deficiency, prolidase deficiency, RIPK1 gene defect were documented. All patients had duodenal and/or colonic biopsies which were evaluated for villus morphology, brush border, endocrine cells, epithelial changes, type and degree of inflammation, granulomas, lipid accumulation.

Results: Mean age of admission was 1.19 decimal years. Diarrhea was watery in 74%, fatty in 18.5%, bloody in 11.1% and started within two months of birth in %59,2. Consanguinity and sibling death due to diarrhea was present in 74% and 25.9%. Endoscopically, 88% showed duodenal, 51,8% had colonic mucosal abnormalities with 20% requiring repeat biopsies for diagnosis. Genetic diagnosis (SAR1B, STX, MTP, CYBB, MYO5B, dGAT, RIPK1, PEPD mutations, IL-10 R, IL-21 deficiencies) was possible in 55.5%. Histopathologically, villous and brush border abnormalities were observed in 14.8% and in 18.5%, respectively while 40.7% showed active colitis. Electron microscopy revealing microvillous inclusions and lipid vacuolization was diagnostic in 14.8% of the cases.

Conclusion: Diagnosis of congenital enteropathies is difficult and requires close collaboration between the members of an experienced multidisciplinary team comprising paediatric gastroenterologists, immunologists, geneticists, and pathologists. In the present series, pathologic diagnosis was possible in 37% of the cases suggesting that overlaps in the histopathology of these entities are common and full picture may not be present in initial biopsies. Therefore, the pathologist should be aware of such pitfalls and should employ sophisticated techniques for an accurate diagnosis, as necessary.

OFP-06-026

Mesenchymal tumours of the digestive system: not all are GISTs!

E.D. Kuz*, S. Yuksel, G. Kaygusuz, B. Savaş, A. Ensari

*Ankara University Medical School, Turkey

Background & objectives: Mesenchymal tumours of the digestive system among which GISTs are the most common, show great diversity similar to their soft tissue counterparts. We share our sixteen years’ experience by presenting a large cohort of mesenchymal tumours of digestive system.

Methods: A total of 851 mesenchymal tumours was diagnosed in our institution between 2005-2021. We encountered 19 out of 26 types of mesenchymal tumours included in WHO blue book of GI tract. Five additional sarcomas (dedifferentied, well-differentiated liposarcomas, myxoid, pleomorphic liposarcomas and undifferentiated pleomorphic sarcoma) were identified as well. Retroperitoneum-only tumours were excluded. Tumours were analysed for age, gender, and localization.

Results: Among 851 cases, mean age was 62.91 (Range:5-98) and 54.8% were women. Top five localizations were stomach (27.3%), colon (25.7%), liver (20.3%), small intestine (14.5%), esophagus (9.8%) while pancreas (0.6%), anal canal (0.5%), appendix (0.4%) and biliary tract (0.3%) were rare. Five most common diagnoses were GISTs (%24.7), hemangiomas (18.2%), leiomyomas (16.3%), lipomas (15.7%) and inflammatory fibroid polyps (IFP) (8.5%). Stomach was the most common site for GIST (65.2%), followed by small intestine (20.5%) and colon (5.2%). Hemangiomas preferred liver (96.1%). Esophageal leiomyomas (50.4%) outnumbered colonic (28.1%) and gastric ones (16.5%). Colon was the predominant site for submucosal lipomas (78.4%). IFPs were mostly encountered in stomach (68.1%).

Conclusion: The present series contains a whole spectrum of mesenchymal lesions ranging from benign lesions like angiomyolipomas or perineuromas to malignant ones like angiosarcomas or even rhabdomyosarcomas. The majority was benign mesenchymal tumours with fewer sarcomas similar to the literature. As expected, GISTs were the most common mesenchymal tumours of digestive system in our series. Except for leiomyomas which had a higher incidence in the esophagus, site distribution of tumours was similar to published data.

OFP-06-027

Clinical-demographical characteristics and incidence of young-onset colorectal carcinoma

S. Demir*, I. Aydin, N. Ekinci, I.E. Cakir, A. Akder Sari

*Izmir Katip Celebi University, Ataturk Training and Research Hospital, Department of Pathology, Turkey

Background & objectives: While the overall incidence of colorectal carcinoma (CRC) tends to decrease by the help of screening methods, the incidence under the age of 50 is gradually increasing. Young-onset CRCs tend to present at advanced stages and generally follow poor prognosis.

Methods: All patients aged under 50 years who were diagnosed with CRC in resection specimens between 2006-2019 were included in the study. Data were obtained from the hospital database. The cases were reviewed according to clinicopathological characteristics.

Results: A total of 188 young-onset CRCs were identified which constituted 15.8% of all CRCs. The ratio of young onset cases from 2006-2019 per year was as follows: 15.9%, 13.6%, 11.6%, 12.5%, 11.7%, 23.7%, 17.9%, 16.9%, 27%, 12.5%, 8.7%, 15.8%, 13.7%, 20.8% respectively. The most common histological type was adenocarcinoma (84%), followed by mucinous (13.3%) and signet-ring cell carcinoma (2.7%). Male to female ratio was 51.6 vs 48.4%. According to the stage, the distribution was as follows; stage 1(8%), stage 2(36.7%), stage 3(41%) and stage 4(14.4%). Mismatch repair gene (MMR) immunohistochemical status information was available for 44 patients performed after 2017. MMR-deficiency was detected in 12/44 (27%) of them.

Conclusion: According to our single centre data, in contrast to the literature, the incidence of young onset CRCs is variable and does not seem to follow an increasing trend. Also, presentation at early stage vs advanced stage seem to be similar. These variations could be due to epidemiological differences. The rate of microsatellite instability is in keeping with the literature and it is approximately 2 times higher in comparison to reported ratios in adult population.

OFP-07 | Digestive Diseases Pathology - Liver/Pancreas

OFP-07-001

Pancreatobiliary adenocarcinomas: an immunomarker panel proposal

M. Pinho*, R. Moiteiro da Cruz, S. Carneiro, C. Ferreira, R. Luís

*Department of Pathology, Hospital de Santa Maria, CHULN, Portugal

Background & objectives: Pancreatobiliary adenocarcinomas comprise various entities that largely share an inconspicuous evolution leading to abrupt disease in metastatic setting, posing particular challenges to the histopathological differential diagnosis. Herein, we propose a panel of immunomarkers for a reliable approach to such tumours.

Methods: Tissue microarrays (TMAs) of 3mm diameter cores were prepared from surgical specimens of 45 primary pancreatobiliary adenocarcinomas of the liver, extrahepatic bile ducts, gallbladder, ampulla of Vater and pancreas, along with 5 colorectal and 5 gastric adenocarcinomas, included as controls. A panel of CK7, CK20, CK19, CDX-2, SATB2, Villin, CEAp, IMP3, S100p and Ca19.9 was evaluated.

Results: All TMAs were independently assessed by two observers: undisputable staining (whether focal or diffuse) was considered positive, whereas complete or near total absence of expression was deemed negative; instances with equivocal staining were disregarded. The majority of markers displayed high positive predictive values, when compared to both proximal and distal gastrointestinal tract tumours (CK7: 100%, CK19: 91%, villin: 71%, CEAp: 83%, IMP3: 83%, S100p: 88% and Ca19.9: 92%) as well as when plotted only against gastric carcinomas (CK7: 100%, CK19: 98%, villin: 83%, CEAp: 92%, IMP3: 83%, S100p: 95%, Ca19.9: 94%). The remaining markers also presented robust overall negative predictive values (CK20: 98%, CDX-2: 92%, SATB2: 97%).

Conclusion: A panel comprising the aforementioned antibodies may provide compelling evidence for a definite diagnosis of pancreatobiliary adenocarcinomas in metastatic setting, both through the presence and absence of immunoexpression. However, we are aware our data stems from a restricted series and limited framework, particularly regarding the imbalanced number of gastrointestinal controls, and does not reflect the heterogeneity inherent to distinct grades and entities, namely pertaining to different organs and tumoral microenvironment.

OFP-07-002

Clinicopathological characterization of steatohepatitic variant of hepatocellular carcinoma (SH-HCC)

L. Trapani*, A. Beaufrère, C. Hobeika, F. Cauchy, V. Paradis

*Department of Pathology, Beaujon Hospital, France

Background & objectives: Steatohepatitic hepatocellular carcinoma (SH-HCC) is a recently described variant of HCC with no consensus definition and unclear prognosis. The objectives of this study were (1) to evaluate the frequency of SH-HCC and its prognosis, (2) to describe their histological characteristics.

Methods: We conducted a retrospective study including 298 patients surgically treated for HCC between 2012 and 2019. Histological features of tumours were reassessed by two pathologists. The diagnosis of SH-HCC was retained if at least 4 of the 5 described criteria were present (steatosis, ballooning, Mallory-denk bodies, fibrosis, inflammation) and if the SH contingent was >50% of the tumour area.

Results: Of the 298 HCCs, 39 (13%) were classified as SH-HCC. SH-HCCs were observed more frequently in a context of metabolic syndrome and chronic alcohol intake compared to other HCCs (56% vs 26%, p<0.001 and 28% vs 15%, p=0.039, respectively). Ballooning, fibrosis and inflammatory were observed in all SH-HCCs whereas steatosis and Mallory-denk bodies were observed in 92% and 74% of SH-HCCs. No significant difference was observed with other HCCs in terms of histoprognostic factors such as tumour differentiation (well-differentiated tumour, 41% vs 31%, p=0.239). SH-HCCs had similar recurrence-free and overall survival compared to other HCCs (14 months vs 13 months, p=0.985 and 23 months vs 24 months, p=0.894, respectively).

Conclusion: SH-HCC is a relatively frequent variant (13% of HCCs in our cohort) with specific macroscopic and microscopic features that distinguishing it from other HCCs. It occurs mainly in a context of metabolic syndrome or chronic alcohol intake. SH-HCC seems to have a similar prognosis compared to other HCCs, particularly in terms of histoprognostic factors and survival.

OFP-07-003

Ferroptosis in intrahepatic cholangiocarcinoma: an immunohistochemical study

S. Sarcognato*, D. Sacchi, L. Fabris, G. Zanus, E. Gringeri, M. Niero, M. Guido

*Department of Pathology, Azienda ULSS2 Marca Trevigiana, Treviso, Italy

Background & objectives: Ferroptosis is a regulated, iron-mediated, cell death, induced by glutathione peroxidase4 (GPX4) inhibition. GPX4 is overexpressed in aggressive cancers and directly inhibited by ferroptosis-inducer drugs. We investigated ferroptosis markers in intrahepatic cholangiocarcinoma (iCCA), since no data are reported so far.

Methods: Sixty-two consecutive patients, who underwent hepatic resection for iCCA, were retrospectively enrolled. Immunostaining for transferrin-receptor 1 (TFR1) and GPX4, and Pearls histochemical stain for iron deposition were performed to evaluate ferroptosis. Immunostaining for STAT3 was performed to investigate the well-known anti-apoptotic background of iCCA, which justifies its chemotherapy resistance.

Results: STAT3 was expressed in the majority of cases (88.7%), confirming the anti-apoptotic milieu in iCCA. A high STAT3 expression was associated with a worse prognosis (OS p = 0.006; DFS p = 0.001). None of the cases showed iron deposition, and a complete negativity for TFR1 was observed in 93.5% of cases. GPX4 was overexpressed in 72.6% of cases, and its overexpression correlated with poor histological prognostic parameters, such as vascular and perineural invasion and high grade (p <0.005 for all) and a worse prognosis (OS p = 0.005; DFS p = 0.0002).

Conclusion: Our study firstly demonstrated that ferroptosis is not an activated form of regulated cell death in iCCA. GPX4 overexpression is observed in most cases and correlates with poor outcome. These promising results pave the way to the possible therapeutic use of ferroptosis inducers in iCCA to overcome cancer cell drug resistance.

OFP-07-004

EUSFNB of pancreatic lesions: a prolific outcome

T. Pasupati Meenakshi*

*Clinipath Sdn Bhd, Malaysia

Background & objectives: Endoscopic ultrasound (EUS)-guided fine-needle biopsy (FNB) is replacing conventional EUSFNA in the diagnosis and management of pancreatic mass. The aim is to document the diagnostic precision, accuracy and IHC studies of EUS-FNB of pancreatic lesions when compared to EUSFNA.

Methods: This is a cross sectional study of EUSFNB samples of pancreas received in Clinipath laboratory in the year 2020, with clinical, CT scan and endoscopy correlation. A total number of 131 EUSFNB samples of pancreatic lesions were documented for histological features and IHC outcome, the latter performed, wherever it was deemed necessary.

Results: A wide range of pancreatic lesions, mostly well to poorly differentiated primary adenocarcinomas of the pancreas, along with a small number of neuroendocrine tumours were documented. Spindle cell tumours, mucinous cystic neoplasms, serous papillary lesions, lymphomas, and cases of chronic pancreatitis were also seen. Metastatic lesions from the lung and kidney were also noted. IHC helped to differentiate the primary and metastatic lesions with precision. Correlation with clinical picture, tumour markers and CT scan findings were undertaken in all cases.

Conclusion: EUSFNB has emerged to be the most safe, reliable diagnostic procedure replacing the conventional EUSFNA and cell block of pancreatic lesions in Malaysia. The precision of the procedure and accuracy of the results of EUSFNB samples have considerably increased in the year 2020. This initial study carried out for the first time in Malaysia in a private laboratory set up is to document the increasing diagnostic capability of EUSFNB in the management of pancreatic lesions.

OFP-07-005

Integrated signature of tumour budding and immunoarchitectural features significantly improves prognostic stratification of patients with pancreatic cancer

E. Karamitopoulou-Diamantis*, A. Andreou, M. Tinguely, B. Gloor

*University of Bern, Switzerland

Background & objectives: Tumour budding and the immune cell infiltrates are known to be important prognostic factors in pancreatic ductal adenocarcinoma (PDAC). However, they are assessed independently. Here we combine their assessment in order to achieve a more precise risk stratification for PDAC-patients.

Methods: We evaluated the cell-cell interactions and spatial relationship between tumour budding cells and immune cells at the tumour centre (TC) and invasive front (IF) of two PDAC-cohorts (n=112:training and n=30:validation) by using multiplex immunofluorescence for CD3, CD4, CD8, FOXP3, CD68, CD206, PD-1, PD-L1 and pancytokeratin, followed by automated image analysis for quantification, proximity analysis and a Random-Forest variable selection approach.

Results: High numbers of tumour buds (HR=4.678; 95% confidence interval (CI) 1.204-17.644), low numbers of CD3+CD8+PD-1-T cells within a radius of 50 μm from the budding cells at the TC (HR=5.010; 95% CI 1.315-19.585) and high CD68+CD206+ tumour associated macrophages (TAMs) (HR=5.563; 95% CI 1.544-23.742) within a radius of 50 μm from the budding cells at the IF area, were associated with reduced disease specific survival. A prognostic signature integrating all the above three parameters achieved a more significant cohort stratification (HR=11.585; 95% CI 3.649-46.813). This was confirmed in the validation cohort (HR=10.333; 95% CI 2.742-38.563).

Conclusion: An Integrated Budding Immune Signature (IBIS) stratified PDAC-patients into prognostic subgroups more efficiently than each biomarker alone, improving the prognostic power and risk stratification independently of other known prognostic factors, including tumour grade or tumour stage.

OFP-07-006

High tumour mutational burden identifies a subset of pancreatic cancer patients with prolonged survival and improved anti-tumour immunity

E. Karamitopoulou-Diamantis*, A. Andreou, M. Tinguely, B. Gloor

*University of Bern, Switzerland

Background & objectives: Imunotherapy in pancreatic cancer (PC) has focused on microsatellite-instable (MSI-high) cases, representing <2% of patients. Identifying microsatellite-stable (MSS) PCs with high tumour mutational burden (TMB-H) and exploring their microenvironment might expand the number of PC-patients that could benefit from immunotherapy.

Methods: We evaluated TMB in 110 MSS PC-specimens using the Oncomine Tumour Mutation Load Assay (ThermoFisher) and the Comprehensive Cancer Panel. Moreover, whole tissue sections of 12 TMB-H cases (i.e. TMB≥10; TMB-H) and 15 cases with low TMB (TMB<10, TMB-L) were immunoprofiled by multiplex immunofluorescence for CD3, CD4, CD8, FOXP3, CD20, CD68, PD-1, PD-L1 and DC-LAMP, followed by automated image analysis.

Results: Twelve TMB-H cases (10.9%; median TMB: 14.87, range: 10.21-34.96) were detected. TMB-H cases exhibited significantly increased CD3+CD4+FOXP3- T cells (P=0.0398), CD20+ B cells (P=0.0296) and DC-LAMP+ dendritic cells (DC; P=0.0093) when compared with TMB-L cases. No significant differences were observed regarding all other immune cell infiltrates or their subsets. No correlation was found between TMB and the PD1/PD-L1 staining pattern. TMB-H cases exhibited an improved overall survival (median OS:27 months, range:5-171) and progression free survival (median PFS:21.5 months, range:3-165) compared with the TMB-L cases (median OS:13 months, range:3-161; median PFS:6.5 months, range:3-157), each P<0.001.

Conclusion: TMB-H PCs display improved anti-tumour immunity mediated by increased DC numbers, which have the capacity to initiate and regulate T cell responses, and increased counts of CD3+CD4+FOXP3-T cells, known to exhibit direct cytotoxicity against tumour cells as well as potentiate the DC. Moreover, CD20+ B cells and DC can prime T cells to target tumour cells due to antigen presentation. These results partially explain the improved survival of TMB-H patients and suggest that they might be good candidates for immunotherapy.

OFP-07-007

Intra and extra-hepatic cholangiocarcinoma distinction – useful ancillary markers

J. Gama*, R. Oliveira Caetano, P. Teixeira, F. Silva, R. Martins, J.G. Tralhão, M.A. Cipriano

*Pathology Department, Hospitais da Universidade de Coimbra, Centro Hospitalar e Universitário Coimbra, Portugal

Background & objectives: Cholangiocarcinoma originates anywhere in the biliary tract epithelium. Frequently the pathologist is questioned if the tumour sample is from a primary liver tumour or a metastasis. This study assessed the value of ancillary techniques in that distinction.

Methods: A retrospective transversal study was completed using archival biological material from 32 patients with cholangiocarcinomas, 16 intra-hepatic (IHC) and 16 extra-hepatic (EHC), 25 male and 7 female, diagnosed between 2009 and 2014 at the Coimbra University Hospital.

Expression PAS/D, EMA, Gamma-GT markers were assessed by histo- and immunohistochemistry. Clinical and pathological data was retrieved from the hospital database.

Results: The median age of presentation was 69.7±9.7years. After a median follow-up of 12±29.4months, the overall survival (OS) was 12±3.7months. There was no difference in survival between the IHC and EHC (p=0.168).

EMA expression was associated with the site of origin: apical EMA expression in 56.3% of IHC and complete EMA expression in 87.5% of the EHC (p=0.012). The complete EMA expression was also associated with a worse OS (5 vs. 66months, p=0.008) on univariate and multivariate analysis (HR=3.2, 95% CI 1,21-8.09, p=0.013).

Expression of Gamma-GT was present in 43,8% of IHC and 6,3% of EHC (p=0.019).

PAS/D did not disclose statistical correlation with either OS or tumour location.

Conclusion: The expression of Gamma-GT and EMA were helpful in determining the origin of cholangiocarcinoma, and EMA complete expression was predictor of worse OS. These markers should be tested in any cholangiocarcinoma biopsy.

OFP-07-008

Solid pseudopapillary neoplasm of the pancreas – a 21-year long experience in a tertiary Portuguese institution

R. Moiteiro da Cruz*, M. Pinho, R. Luís, C. Ferreira

*Department of Pathology, Hospital de Santa Maria, CHULN; Faculdade de Medicina da Universidade de Lisboa, Portugal

Background & objectives: Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare low-grade malignant tumour which accounts for 0,9-2,7% of all exocrine pancreatic neoplasms, with higher incidence in women of young age. Herein, we present our expertise through a 21-year long series.

Methods: Data of all cases of SPN diagnosed in our institution pertaining to the period of 2000-2020 were retrieved. The clinicopathological, gross and histopathological features along with performed immunomarkers (beta-catenin, CD56, CD10, progesterone receptors (PR), chromogranin and synaptophysin) were reviewed and summarized; additionally, the expression of galectin-3, AMACR and TFE-3 was also retrospectively evaluated in different tumour areas.

Results: A total of 9 cases were assessed: 6 patients were female (mean:30years; range:12-58years) and 3 were male (mean:50years; range:31-75years). The tumours were large (sized 3-8cm; mean:5cm), unifocal, well-demarcated and cystic-solid, with no preferential topography. Histologically, the classical features were present; most had perineural invasion and focal pancreatic infiltration, along with singular findings: areas of oncocytic differentiation, strands of neoplastic cells within a myxoid/edematous stroma, extracellular iron deposits and infrequent mitoses (range:0-4 high-power-fields). Beta-catenin, CD56, CD10, PR, AMACR and TFE-3 were diffusely positive, whereas focal expression for synaptophysin and negativity for galectin-3 and chromogranin were observed. Noteworthy, nodal, and hepatic metastases were reported in two cases.

Conclusion: Histological features of SPN are quite specific, although diverse. The differential diagnosis becomes intricate in the presence of small-solid lesions or large-unilocular cysts, especially in male patients. Beta-catenin, AMACR and TFE-3 can aid pathologists to differentiate this entity from other pancreatic circumscribed tumours, namely neuroendocrine tumours; interestingly, galectin-3 was negative in all cases, unlike reported in the literature. SPN may uncommonly behave aggressively with no well-established malignant criteria; however our case with hepatic metastization showed a higher mitoses count.

OFP-08 | Electron Microscopy

OFP-08-001

Diagnostic challenges in ichthyosiform dermatoses

A. Cohn*, C. Salavastru, M. Gherghiceanu

*Emergency University Hospital, Bucharest, Romania

Background & objectives: Neonatal and infantile erythroderma is a rare skin disorder, frequently associated with ichthyoses or immunodeficiency syndromes. This study emphasizes the ultrastructural features found in ichthyosiform conditions in order to establish a relationship between electron microscopy findings and genetic mutations.

Methods: Two infants with clinical ichthyosiform dermatoses, one with erythroderma, were biopsied for diagnostic purpose. Skin biopsy specimens were processed at "Victor Babeș" National Institute of Pathology for both light microscopy and electron microscopy (EM) studies. Clinical data were gathered from patients’ medical record. The cases were evaluated according to age, sex, clinical diagnosis, genetic profile, and histopathologic and ultrastructural findings.

Results: Case 1: A 7-day-old boy with erythroderma was ultimately diagnosed with Omenn syndrome (RAG-1 gene mutation). Light microscopy revealed acanthosis, parakeratosis, and perivascular lymphocytic infiltrate in the dermis. EM showed an increased number of lamellar bodies in stratum granulosum (SG). Lipid vacuoles were found in stratum corneum (SC), both intercellular and intracellular.

Case 2: Skin biopsy from a 2-month-old boy presents microscopically orthohyperkeratosis with lipid droplets in SC and a reduced SG. Ultrastructural study of SG revealed a decreased number of keratohyalin granules and keratinocytes with cytoplasmic vacuoles and angulated, electron-lucent structures. Cholesterol clefts, aggregates of membranous structures and lipid vacuoles were found in corneocytes.

Conclusion: This study highlights the significant overlap between ultrastructural features found in Omenn syndrome and autosomal recessive congenital ichthyosis (ARCI) type I.

The second case presents particular EM findings, consistent with ARCI type II/III. Even if the initial presentation pointed towards ichthyosis vulgaris, the diagnosis of ARCI was genetically confirmed by NIPAL-4 gene mutation. At follow-up, the patient developed erythroderma.

As etiologic diagnosis of ichthyosiform conditions is often difficult, EM examination may point out some genetic defects before becoming clinically apparent.

OFP-09 | Endocrine Pathology

OFP-09-001

TROP2: a potential new marker in diagnosis of thyroid neoplasms

Z. Turan*, S. Erkilic

*Department of Pathology, Medical Faculty, Gaziantep University, Turkey

Background & objectives: The human trophoblast cell surface antigen (TROP-2) which is a transmembrane glycoprotein, has recently been investigated as a useful marker of thyroid epithelial neoplasms. In this study, we aimed to show the diagnostic utility of TROP2 in thyroid neoplasms.

Methods: A total of 306 cases, including 170 cases of different PTC variants, 50 cases of benign and non-neoplastic lesions, and 86 cases of other neoplasms (NIFT-P, follicular carcinoma, Hürthle cell carcinoma, poorly differentiated carcinoma, anaplastic carcinoma, and medullary thyroid carcinoma), were included in this study. Only membranous staining with TROP2 was considered positive.

Results: In PTC, classical(n=35), tall cell(n=41), follicular(n=39), solid(n=19), hobnail(n=10), Warthin-like(n=10), columnar(n=7) and oncocytic variant(n=9), respectively, 100%, 97.6%, 5.1%, 42.1%, 90%, 90%, 28.6% and 33.3% positivity were seen. A negative reaction was observed in all 50 cases of benign and non-neoplastic lesions (follicular adenoma(n=10), Hürthle cell adenoma(n=10), hyperfunction(n=10) and multinodular goiter(n=20)). Negative reactions were observed in 83 (n=86) of other thyroid neoplasms which consist of NIFT-P(n=20), follicular carcinoma(n=18), Hürthle cell carcinoma(n=18), poorly differentiated carcinoma(n=10), anaplastic carcinoma(n=10) and medullary thyroid carcinoma(n=10). Only focal positivity were seen in 3 Hürthle cell carcinoma cases. The sensitivity for tall cell and classical variant was 97.5% and 100%, respectively, and specificity was 100% for both.

Conclusion: TROP2 was seen to be a very useful marker in differentiating PTC, especially in particular variants (classic, tall cell, hobnail and Warthin-like variant), from benign and non-neoplastic lesions and other neoplasms of the thyroid.

Funding: Gaziantep University Scientific Research Projects Governing Unit (BAPYB)

OFP-09-002

Poor prognostic factors of papillary thyroid microcarcinomas

Z. Turan*, S. Erkilic

*Department of Pathology, Medical Faculty, Gaziantep University, Turkey

Background & objectives: Papillary thyroid microcarcinomas (PMC), by definition, are tumours 1 cm or less and are considered to have a good prognosis. However, PMCs may sometimes cause lymph node metastasis, distant metastasis, and even disease-related death.

Methods: Pathology reports of patients who underwent thyroidectomy were analysed. 1194(44.9%) of 2660 papillary thyroid carcinoma cases were PMC. 58 cases (4.85%) who had lymph node metastasis and/or received multiple doses of radioactive iodine (RAI) and/or tumour-related death, were re-examined in detail, and were assigned as the study group. The remaining 1136 cases were included in the study as control group.

Results: In the study group, 44 had lymph node metastases, 4 had distant metastases, 14 had disease-related death. The remaining 14 patients received multiple doses of RAI therapy for recurrences or other causes. The tumour was bilateral in 29 patients (50%) and multifocal in 36 patients (62%). Microscopic extrathyroidal extension (ETE) was detected in 32 patients (55.2%). 32 patients (55.2%), whether focal or diffuse, had a tall cell histological variant component. Tumour diameter was >0.5 cm in 35 patients (60.3%).

We found that aggressive course of the tumour was associated with; age at diagnosis (≥ 55 age), bilaterality, male gender, tumour diameter (>0.5 cm), microscopic ETE, lymph node metastasis, distant metastasis, tumour-thyroid capsule relationship, and aggressive histological variants.

Conclusion: Although a very good prognosis is mostly observed in papillary microcarcinoma, it should be kept in mind that some clinical and histomorphological features may cause poor clinical course.

OFP-09-003

Extra-adrenal paraganglioma clinical and histopathological features: a 16-year period institutional case review series

T. Oliveira*, J. Boavida, D. López-Presa

*Department of Pathology, Hospital de Santa Maria, CHULN, Portugal

Background & objectives: Extra-adrenal paragangliomas are non-epithelial tumours originating from paraganglion cells of the autonomic nervous system, with a biological behaviour ranging from indolent to metastasizing. Herein, we reviewed and evaluated 36 paraganglioma cases received by our institution during a 16-year period (2000-2015).

Methods: The clinical history and slides of all cases were reviewed by an anatomic pathology resident and a senior pathologist and assessed for: tumour size, location, multifocality, microscopic characteristics, catecholamine secretion profile, Grading of Adrenal Pheochromocytoma and Paraganglioma (GAPP) score, hereditary conditions, metastasis and cancer-related death.

Results: Eighteen cases were from the head and neck (13 from the carotid body, 3 jugulotympanic, 1 laryngeal and 1 non-specified), 3 were thoracic and 15 were abdominal/pelvic. Two and one patients had a Succinate dehydrogenase complex subunit D (SDHD) and subunit B (SDHB) gene mutations, respectively, and 1 had Von Hippel Lindau disease; save for the later, they had multiple tumours and a mean age of 38 years. GAPP score grading was feasible on 14 cases: 6 were well-differentiated and 8 were moderately differentiated type. All three patients that showed metastasis were moderately differentiated type and sporadic, of which only one died due to disease progression.

Conclusion: In our study, the factors that were possibly related to a worse prognosis were the GAPP score grade, size, and location. While these tumours are biologically unpredictable, multivariable prognostic tools, such as the GAPP score, can aid in outlining an appropriate patient’s management. Despite its small sample size, our case series’ findings are consistent with current reported data.

OFP-09-004

Immunological landscape of medullary thyroid carcinoma: PD-1 and PD-L1 expression analysis.

F. Galuppini*, S. Censi, M. Iacobone, M. Rigon, A.P. Dei Tos, C. Mian, G. Pennelli

*University of Padua, Department of Medicine (DIMED), Pathology Unit, Via Gabelli 61, 35121 Padova, Italy

Background & objectives: Medullary thyroid carcinoma (MTC) is an indolent neoplasm with lymph-node and distant metastases and there is no effective therapy to achieve a remission in advanced stages. Our study paid attention on the role of the immunoregulatory PD1 / PD-L1 axis.

Methods: The study considered 130 patients with histological diagnosis of MTC (104 sporadic and 26 hereditary MTC) with a follow-up time of 39 months. All patients were characterized for clinical-pathological variable and disease progression at the end of follow-up. Immunohistochemical analysis were performed for CD8, PD-1 and PD-L1. PD1 and PD-L1 staining was evaluated according to the Combined Positive Score system.

Results: The immunoreaction for PD-L1 was positive in 32.3% of MTC. PD-L1 was more expressed in patients with sporadic disease (p = 0.01) and in patients with aggressive disease characterized by the presence of lymph node metastases (p < 0.0001) and elevated Calcitonin values at diagnosis (p = 0.003). The expression of PD-L1 correlated with the expression of PD1 (p <0.0001) and the presence of positive CD8 T lymphocytes (p < 0.0001). At the end of follow-up, PD-L1 positivity correlated with the progression of disease. At the multivariate analysis, the loss for PD-L1 expression, together with a lower stage at diagnosis, were the only prognostic markers associated with biochemical cure.

Conclusion: This study confirms the importance of the PD-L1 / PD1 interaction also in MTC. The correlation between PD-L1 expression and disease progression opens the way to the possibility of using immunomodulatory drugs with PD-L1 as target in MTC, which could significantly modify the clinical course of the disease, especially in those patients who cannot be already cured.

OFP-09-005

The functional activity of thyroid nodules during aging

A. Filin*, V. Danilenko, A. Churina, E. Chupandina, M. Bobrovskikh, A. Bobrovskikh, D. Bugrimov, E. Verbitskaya, E. Ulitina, P. Markin, I. De-George, S. Selyavin, V. Shishkina

*Voronezh State Medical University, Russia

Background & objectives: The study of age-related changes in the thyroid tissue is important for understanding the essence of the processes occurring in the organ. Is there a relationship between background changes and nodal pathology?

Methods: The material was 73 thyroid glands, autopsy material without clinical and laboratory signs of endocrine pathology. Follicle diameter, epithelial height, colloid accumulation index, follicular epithelium volume and stromal volume were studied in histological preparations. Age-related changes were analysed both in the background tissue and in nodular pathology, taking into account age groups.

Results: In the age group over 60 years old, there was increased the volume of stroma, decreased of the epithelium volume, a decreasing the height of the epithelium and increasing the diameter of the follicles compared with the group under 60 years old. Characteristics of the nodes: the same morphological indicators demonstrated that the decreasing functional activity in the tissue of the nodes does not occur with age, as in the background tissue. There is no pronounced process of sclerosis. Decreasing the size of follicles, the index of colloid accumulation, increasing volume of the epithelium speaks of a higher functional activity of the nodules in the group over 60 years old.

Conclusion: Age-related changes in the background tissue of the organ indicate a natural decrease in the functional abilities of the thyroid gland. The data obtained may be a manifestation of adaptive intraorgan restructuring, which allows the thyroid gland to maintain a high level of functional activity, despite the natural processes of extinction.

OFP-09-006

Clinicopathological and biological features of well-differentiated Grade 3 neuroendocrine neoplasms of various primary origins

V. Delektorskaya*, E. Evdokimova, G. Chemeris, E. Artamonova

*National Medical Research Center of Oncology, Russia

Background & objectives: Grade 3 neuroendocrine tumours (G3 NETs) represent a group of well-differentiated neuroendocrine neoplasms that demonstrate a Ki-67 index higher than 20%. Little is known regarding clinicopathological differences between G3 NETs from different primary sites, most commonly gastroenteropancreatic (GEP) and lung.

Methods: The study included 71 resected G3 NET cases, which were reviewed for morphology and immunohistochemistry and graded according to the WHO 2019 criterions. Median age at the diagnosis was 50 ± 12 (range 20 – 73 ) years and 48 (65.8%) were females. The results were correlated with clinicopathologic data, Ki-67 index, somatostatin receptor 2A expression and disease-free survival (DFS).

Results: Of the 71 well-differentiated G3 NET cases, 40 (56.3%) were GEP, 17 (23.9%) lung, 12 (16.9%) other (ovary, thymus, unknown primary). The most common primary site was pancreas, followed by gastric. The mean Ki-67 index was 35.4% (min. 23.0% - max. 65.0%). Metastatic disease was present in 45 (67.4%) patients. We found that tumours arising from GEP site, compared to lung, had significantly worse survival (p<0.05). Median DFS in GEP, lung and all other sites of G3 NETs was 9.7, 16.6 and 2.5 months, respectively. The most of G3 NET patients (56, 78.8%) had SSTR 2A-positive immunohistochemical status. SSTR 2A expression did not correlate to clinical parameters, Ki-67 index, DFS survival.

Conclusion: Well-differentiated G3 NENs with elevated proliferation may develop anywhere in the digestive tract, lung, and rare sites. G3 NENs of different primary origins are a heterogeneous group of neoplasms regarding clinicopathological and biological characteristics, behaviour and survival outcomes. Among G3 NEN cohort, tumours which originate from a GEP site have a worse survival compared to lung. The most of G3 NETs have SSTR 2A-positive status which provides additional important information and can help guide management of these group of patients.

OFP-09-007

Diagnostic concordance study in non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) and bordering entities

M.R. Bella-Cueto*, J.M. Cameselle-Teijeiro, A. Ugalde, H. Quiceno, E. Roselló, P. Meseguer, T. Meizoso, J.C. Oliva, D. Zamora, S. Lopez Agulló, E. Teixeira, M. Paja, C. Iglesias

*Hospital Universitari Parc Taulí, Institut d'Investigació i Innovació Parc Taulí I3PT, Universitat Autònoma de Barcelona, Sabadell, Spain

Background & objectives: The diagnosis of Non-Invasive Follicular Thyroid Neoplasia with Papillary Nuclear Features (NIFTP) is based on morphological criteria that may be subjective. The aim of our study was to assess the concordance between pathologists regarding this entity and its diagnostic criteria.

Methods: After a previous multicentre study about NIFTP incidence, slides considered representative of typical NIFTP (8), doubtful for NIFTP (8) or without NIFTP criteria (6) were selected and reviewed by 8 pathologists with special dedication to endocrine pathology, assessing nuclear criteria, presence of papillae, psammoma bodies, capsule, capsular invasion, vascular invasion and diagnosis. Brennan-Prediger kappa coefficient was established to assess agreement.

Results: The overall agreement reached a kappa value of 0.60. For the different variables, kappa values were: nuclear shape: 0.33; nuclear membrane: 0.39; chromatin: 0.25; nuclear score: 0.16; papillae: 0.48; psammoma bodies: 0.77; capsule: 0.50; capsular invasion: 0.60; vascular invasion: 0.86 and diagnosis: 0.25. When grouping the cases according to initial diagnosis, kappa values improved in the typical and non-NIFPT groups in terms of overall agreement (0.63 and 0.62), presence of papillae (0.67 and 0.65), capsular invasion (0.66 and 0.67) and vascular invasion (0.93 and 1) respectively, and only in the typical group in terms of diagnosis (0.33), being 0.17 in the doubtful group and 0.24 in the non-NIFTP group.

Conclusion: The degree of agreement regarding NIFTP and bordering entities (hyperplastic nodule, follicular adenoma, follicular or well differentiated tumour of uncertain malignant potential, subtypes of papillary carcinoma, follicular carcinoma) among pathologists with special dedication to endocrine pathology was moderate, with the lowest values being observed in the nuclear characteristics and the highest values in the presence of psammoma bodies, capsular invasion and vascular invasion. Fortunately, the two latter criteria are the most significant to determine a diagnosis of carcinoma.

Funding: Partially supported (JM C-T) by grant PI19/01316-FEDER, Instituto de Salud Carlos III, Spain​.

OFP-10 | Gynaecological Pathology

OFP-10-001

Clear cell carcinoma (CCC) of the cervix is a Human Papillomavirus (HPV)-independent tumour associated with poor outcome

S. Stolnicu*, M. Boros, G. Karpathiou, E. Guerra, C. Mateoiu, A. Reques, J. Bart, A. Félix, D. Hardisson, J.A. Bennett, C. Parra-Herran, K.J. Park

*Department of Pathology, University of Medicine, Pharmacy, Sciences and Technology of Targu Mures, Romania

Background & objectives: Cervical clear cell carcinoma is an HPV-independent adenocarcinoma. While recent studies have focused on gastric type endocervical adenocarcinomas (GTA), little is known about CCCs. We analysed clinico-pathologic parameters and outcomes of CCCs compared to GTA and HPV-associated endocervical adenocarcinoma (HPVA).

Methods: 58 CCCs were collected from 14 international institutions. Correlation between various parameters to overall (OS) and recurrence free survival (RFS) was retrospectively analysed using univariable and multivariable methods. OS and RFS were also compared to those of 36 GTA and 173 HPVA.

Results: Most cases were treated with radical surgery (84.5%), 55.2% adjuvant therapy, were FIGO stage I (70.7%), Silva C pattern (75.9%), and histologic grade 3 (96.6%). Lympho-vascular invasion was present in 31% and lymph node metastases in 22.4%; 10.3% had pelvic metastases, 32.8% had recurrences and 18.96% died of disease. There were no statistically significant differences in OS and RFS between CCC and GTA at 5 and 10 years (p=0.313 and p=0.508 respectively), but there were significant differences in OS and RFS between CCC and HPVA (p=0.003 and p=0.032 respectively). Multivariate analysis showed that OS in influenced by recurrence (p=0.009), while RFS is influenced by FIGO stage (p=0.025).

Conclusion: CCCs have poorer outcomes than HPVA but similar outcomes to GTA. Oncologic treatment significantly influences RFS in univariate analysis but is not an independent prognostic factor in multivariate analysis. Since current therapies do not improve outcome in patients with CCCs, new oncologic strategies are needed.

OFP-10-002

Horizontal tumour extend (HZTE) has limited prognostic significance in endocervical adenocarcinoma (ECA): a retrospective study of 2019 FIGO low-stage 416 cases

S. Stolnicu*, M. Boros, L. Hoang, M.J. Brito, G. Karpathiou, A. Ieni, E. Guerra, P. Dundr, A. Pesci, C. Parra-Herran, R.A. Soslow, N.R. Abu-Rustum, K.J. Park

*Department of Pathology, University of Medicine, Pharmacy, Sciences and Technology of Targu Mures, Romania

Background & objectives: FIGO2019 update on cervical cancer staging removed horizontal tumour extent (HZTE) as a staging variable in microscopic disease (stage IA) due to its poor reproducibility. We aimed to investigate the association of HZTE with survival outcomes in patients with ECAs.

Methods: We retrospectively analysed 416 cases of stage I ECAs from 16 international institutions. Clinico-pathologic parameters and HZTE were retrieved from pathology reports and stage was assigned using 2019 FIGO criteria. Correlation between HZTE, prognostic parameters, overall survival (OS) and recurrence free survival (RFS) were performed using univariable and multivariable analyses.

Results: 71 (56.3%) stage IA cases had HZTE <7 mm and 55 (43.7%) ≥7 mm, while 23 stage IB cases (7.9%) had HZTE <7 mm and 267 (92.1%) ≥7 mm (p=0.0001). 4 (3.2%) stage IA patients developed recurrence compared to 41 (14.1%) stage IB patients (p=0.002). Of the 4 stage IA patients with recurrences (1 IA1, 3 IA2), 3 had tumours with HZTE <7 mm, one of which was IA1. One stage IA2 case had tumour with HZTE ≥7mm. 14 stage IB patients died of disease, all with HZTE ≥7 mm, while no stage IA patients died of disease. In multivariate analysis OS and RFS were not influenced by HZTE.

Conclusion: HZTE does not improve the prognostication of patients with stage IA cancer as per the 2019 FIGO staging system and does not add meaningful prognostic information in early-stage microscopic lesions. Consequently, the FIGO rationale to remove this variable from the staging exercise is justified for ECAs.

OFP-10-003

Primary versus metastatic uterine leiomyosarcoma: differences in hormonal receptors’ expression

M. Souto Moura*, E. Cipriano, P. Lopes, M. Afonso, M. Henriques Abreu, C. Bartosch

*Department of Pathology, IPO-Porto, Portugal

Background & objectives: Uterine leiomyosarcomas (uLMS) have variable expression of hormonal receptors. High tumour expression is associated with good response to hormonal therapy. In this study we aimed to evaluate the concordance of hormonal receptors’ expression between primary uLMS and matched recurrences/metastases.

Methods: Retrospective cohort study (1980-2019), including 29 uLMS patients with recurrent/metastatic disease confirmed by histology; 24 with available primary uLMS. Clinical files and histological slides were reviewed. Immunohistochemistry study with antibodies for oestrogen(ER) and progesterone(PR) receptors was performed. ER/PR were evaluated in primary uLMS and all recurrence/metastatic samples, both using a binary classification (positive/negative) and categories of % positive tumour cells.

Results: Most primary tumours were ER/PR positive (ER: n=21, 87.5%; PR: n=17, 70.8%), with a variable proportion of expression (ER/PR: median=30-40%, range: 0 to 90-100% tumour cells). Thirteen (44.8%) patients had biopsies from more than one metastasis. ER/PR positivity was observed in 19 (65.5%) of first metastases. Most primary tumours had concordant expression with first metastasis (n=16, 66.7%), but 8 had discordant results: 7 changed from positive to negative and 1 from negative to positive. Within those that lost ER/PR expression in metastases, 5 had less than 30-40% of positive tumour cells in primary uLMS. Three showed discordant expression between different metastases of the same patient.

Conclusion: Our results demonstrated that concordance between primary uLMS and metastasis is moderate. This variation most likely is due to biological subclonal selection or changes in metastatic tumour cells, but pre-analytical sample conditions may also influence results. If hormonal therapy guided by hormonal receptors’ expression is considered for patient management in metastatic uLMS, ER/PR evaluation in metastasis may be useful.

OFP-10-004

Macroscopic and histological sentinel lymph node processing in endometrium carcinoma - pathological routine aspects of ultra-staging

T. Rau*, M.V. Deppeler, F. Siegenthaler, S. Imboden, A. Papadia, M.D. Mueller

*Institute of Pathology, University Bern, Switzerland

Background & objectives: Molecular characterization of endometrial carcinoma should be balanced by complete conventional histopathological parameter of the TNM-system. Sentinel lymphadenectomy represents a safe and informative compromise for pN evaluation. The various ultrastaging options enclose macroscopic preparation, frozen section, step-sectioning and pan-cytokeratin immunohistochemistry.

Methods: 834 sentinel lymph nodes from 206 patients treated at the University Hospital Inselspital Bern between 2012-2020 were processed. Macroscopic treatment allowed for complete (26.9%), bi-valved (37.6%) or lamellated (35.5%) lymph nodes. Histologically, specimen were treated with frozen section (5.8%), with step sectioning in 3 steps with 200 microns distance (95.1%) and pan-cytokeratin immunohistochemistry (93.4%), referenced to the first HE (100%).

Results: In total 73 positive lymph nodes were found (8.8%), which could be split to 42 macroscopic, 6 micro metastasis and 25 lymph nodes with isolated tumour cells. In comparison of macroscopy, significantly higher detection rates were found in lamellated sentinel lymphnodes (p<0.004). In the small part of frozen section no macro metastasis were missed and even 2 micro metastasis detected. Pan-cytokeratin immunohistochemistry mainly contributed to the detection of isolated tumour cells and some micrometastasis, but also highlighted relevant pitfalls like endosalpingiosis, mesothelial inclusions etc. An added value to macrometastasis detection by immunohistochemistry was not found, which in 92.9% of cases were detected with the first HE before step sectioning.

Conclusion: Prior to considerations of ultra-staging in terms of immunohistochemistry, routine workup of sentinel lymphadenectomy starts with appropriate grossing with lamellation. Frozen section is a robust technique in terms of macro-metastasis detection. The roles of micro-metastasis and isolated tumour cells have yet to be clarified in terms of prognostication.

Funding: Swiss Cancer League

OFP-10-005

BRCA1/2 mutation status in neoplastic ascites of serous carcinoma of the ovary by Next Generation Sequencing: a reliable method

A. Pesci*, G. Pascoli, G. Settanni, L. Bortesi, M. Ceccaroni, F. Bruni, S. Gori, P. Cassandrini, G. Zamboni

*Dept of Pathology-IRCCS Ospedale Sacro Cuore-Don Calabria, Negrar, Italy

Background & objectives: BRCA1/2 test on ovarian cancer tissue is recommend at the time of diagnosis to predict response to PARP-inihibitors. As malignat ascites is a rich souce to characterized cancer cells, we aim to investigate BRCA1/2 status on this material.

Methods: 24 cases of high-grade serous carcinoma with neoplastic ascites were selected for the study. 5/24 of ascites were neoplastich rich (neoplastic cells >50% x 4), 16/24 had an intermediate cellularity (20-50%) and 3/24 had a poor neoplastic cellularity (< 20%). NGS techniques were used and BRCA1/2 variants were compared with data previously obtained from peripheral blood/tumour tissue.

Results: 21/24 cases were informative for BRCA1/2 status: 10 were BRCA1/2 positive and 11 were BRCA1/2 negative. The concordance of BRCA1/2 between malignant ascites and tumour tissue/blood was 100%. Among the BRCA1/2 positive cases, 9 had germline mutation and 1 had somatic mutation. Of the 3/24 non informative cases 2/3 had poor neoplastic cellularity and 1/3 was neoplastic rich.

Conclusion: Malignant ascites is a good source of neoplastic cells to characterize BRCA1/2 status. As the paracentesis is quick, easy to perform, the NGS analysis on cytologic material can be considered comparable to that obtained in conventional neoplastic materials. This open new prospective to study BRCA1/2 status at the time of diagnosis and follow the evolution of BRCA1/2 mutation during therapy in ovarian cancer as well as in other neoplasia eligible to PARP-inhibitors therapy.

OFP-10-006

Next Generation Sequencing somatic BRCA1/2 mutation in 64 endometrial serous carcinoma

A. Pesci*, F. Zampieri, G. Settanni, L. Bortesi, M. Ceccaroni, F. Bruni, S. Gori, P. Cassandrini, Z. Gianfranco, G. Zamboni

*Dept of Pathology-IRCCS Ospedale Sacro Cuore-Don Calabria, Negrar, Italy

Background & objectives: Endometrial serous carcinoma (ESC) shares with ovarian serous carcinoma morphology, p53 mutation and behaviour but few data are available on somatic-BRCA 1/2 status. We evaluated BRCA 1/2 status by Next Generation Sequencing technique (NGS) in a cohort of ESC.

Methods: From a cohort of 104 cases of high-grade endometrial carcinoma, 80 cases fitted the morphological criteria of serous carcinoma or mixed carcinoma with a serous component. 64 cases were eligible for molecular studies: 48 serous carcinoma, 12 carcinosarcoma and 4 mixed tumour serous-endometrioid. DNA was extracted from paraffin tissue and BRCA 1/2 genes were sequenced using NGS techniques.

Results: 62/64 (96.8%) cases were informative for BRCA 1/2 status: 5/62 (8%) had a pathogenetic variant, 2/5 in BRCA1 and 3/5 in BRCA2. 5/5 (100%) BRCA1/2 positive had a pure serous histology; 5/62 (8%) had a variant of uncertain significance (VUS) (3 cases with a pure serous histology and 2 cases were carcinosarcomas). 8/48 (16%) of serous carcinoma were BRCA 1/2 positive/VUS. 52 cases (84%) were BRCA 1/2 negative.

Conclusion: Somatic-BRCA 1/2 mutation is present in 16% of the cases and in 8% as a pathogenetic variant. If we consider endometrial carcinoma with pure serous histology 10.4% harbour a pathogenetic variant of BRCA1/2 which is the same incidence reported in the literature for high grade serous tubo-ovarian carcinoma. Those data open the scenario of a possible predictive value for target therapy with PARP-inhibitors.

OFP-10-007

Placental pathologic findings of women with SARS-CoV-2 infection during pregnancy and early neonatal follow-up

F. Pereira*, C. Padrão, M. Roquette, L. Monteiro

*Hospital Prof. Doutor Fernando Fonseca, Portugal

Background & objectives: Transplacental transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been suggested in very rare cases reported. Our aim is to evaluate the histopathologic findings in the placentas of women with prenatal SARS-CoV-2 infection and its repercussions on foetuses.

Methods: The study included placentas received for one year in our hospital. Clinical data, histopathologic placental findings, immunostaining for the SARS-CoV-2 N-protein and foetal infection rates were collected. SARS-CoV-2 RT-PCR was performed in all live births. Nucleocapsid protein and spike protein antibodies, and SARS-CoV-2 RT-PCR in some samples from the placenta, foetus blood or foetus fluids were also tested.

Results: Eighteen patients with SARS-CoV-2-positive tests at most 10 days before labour were included. The placentas were divided in two groups depending on the immunohistochemical result for SARS-CoV-2: negative (n=16) and positive group (n=2). One patient experienced minor symptoms, fourteen were asymptomatic and the remaining are unknown. The placentas were subsequently subdivided based on medical history or maternal complications usually associated with placental pathological findings. There were 10 placentas cases with maternal malperfusion (8 in the negative and 2 in the positive group), 3 had foetal malperfusion (all in the negative group), 10 had inflammatory alterations (8 in the negative and 2 in the positive group) and 7 had other findings.

Conclusion: Although the placental/foetal transmission seems to be rare, probably due to the physical and immunological barrier of the placenta, our data suggests the increased presence of maternal/foetal vascular malperfusion and histiocytic intervillositis in placentas delivered from SARS-CoV-2-positive women. All live foetuses had negative nasopharyngeal swabs despite five positive cases to nucleocapsid antibodies (totals=4, IgG=1) due to maternal immunization. At the date of the abstract, we still don't have the results from placenta, foetus blood or foetus fluids for SARS-CoV-2 RT-PCR.

OFP-10-008

Claudin-18 as a surrogate marker for endocervical gastric-type carcinoma

T. Kiyokawa*, L. Hoang, A. Pesci, I. Alvarado-Cabrero, E. Oliva, K.J. Park, R.A. Soslow

*Department of Pathology, The Jikei University School of Medicine, Japan

Background & objectives: Claudin-18 has been shown to be frequently expressed in gastric and pancreatobiliary carcinoma. This study was carried out to investigate whether Claudin-18 could be a surrogate marker to separate endocervical gastric-type carcinoma (GAS) from other types of endocervical adenocarcinoma (ECA).

Methods: ECAs from 7 international institutions were reviewed by a panel of pathologists for consensus histotype based on recently developed International Endocervical Criteria and Classification (IECC). Tissue microarrays were constructed to analyse Claudin-18 expression using immunohistochemistry to simulate assessment in small biopsies. The staining was scored and any staining in >5% of tumour cells considered as positive.

Results: Of 174 ECAs, 125 were of usual-type, 23 GAS, 7 clear cell and 19 other types. Claudin-18 expression was significantly frequent in GASs (15/23, 65.2%) than in non-GASs (3/151, 2.0%; all usual-type) (p<0.01). Positive and negative predictive values of Claudin-18 for GAS were 83.3% and 94.9%, respectively. All Claudin-18 positive GASs showed strong and diffuse staining pattern with staining in more than 75% of tumour cells. None of clear cell type showed positivity for Claudin-18.

Conclusion: Our results suggest that Claudin-18 is a promising surrogate marker to separate GAS from other types of ECA, including clear cell-type.

OFP-10-009

High-risk Human Papillomavirus detection in formalin-fixed paraffin-embedded cervical tissues: performances of Aptima HPV assay and Beckton Dickinson (BD) onclarity assay

G. Kir*, H. Gunel, Z.C. Olgun, W.G. McCluggage

*Istanbul Medeniyet University, Turkey

Background & objectives: There are many scenarios where high-risk HPV (hrHPV) detection in formalin fixed paraffin embedded (FFPE) specimens are important. However, there is no Food and Drug Administration (FDA)-approved and clinically validated technique for detecting hrHPV in FFPE tissues.

Methods: We evaluated two commercially available HPV assays which are FDA approved for use on cytology specimens, the Aptima HPV assay and the BD Onclarity assay, to detect hrHPV in FFPE tissues of cervical HSIL and SCC. A total of 189 cases were tested for hrHPV with the Aptima HPV assay and a subset of cases(n=97) with the BD Onclarity assay.

Results: The sensitivities of the Aptima and BD Onclarity HPV assays were 99.4% (95%CI:96.46%–99.98%) and 75.9% (95%CI:65.27%–84.62%), respectively; the specificity and positive predictive value of the two assays were 100%. Negative predictive values of the Aptima and BD Onclarity HPV assays were 97.3% (95%CI:83.61%–99.61%) and 67.7% (95%CI:58.91%–75.47%), respectively. The kappa value for comparison of the distribution of hrHPV types between the two assays was high(ϰ:0.96). HPV16 was the most common hrHPV type for HSIL and SCC cases. However, SCC cases had higher percentages of HPV16 and HPV18/45 and lower percentages of other hrHPV types compared to HSIL cases.

Conclusion: Both assays are reliable methods for high-risk HPV detection and genotype determination in FFPE specimens, with high PPV and specificity. The Aptima HPV assay has the advantage of higher sensitivity. As far as we are aware, this is the first study comparing the Aptima HPV assay and the BD Onclarity assay in FFPE tissues. Our study results should be tested and confirmed in larger cohorts.

OFP-10-010

Clinicopathological analysis of 41 pole-mutated endometrial carcinomas

E. Guerra*, A. Feu Llauradó, S. Gatius, A. Velasco, M. Pinyol, E. Dorca, A. Vidal, C. Taco, X. Matias-Guiu

*Hospital Universitari de Bellvitge-Idibell, Hospitalet de Llobregat, Spain

Background & objectives: Endometrial carcinomas (ECs) harbouring POLE mutations have been associated with an excellent prognosis, although recurrent and metastatic cases have been described.

Methods: 41 POLE- mutated ECs were selected from our archives (2000-2021). The following clinicopathologic criteria were evaluated: histotype, grade, intratumoral heterogeneity (IH), serous-like (SA) and clear cell-like areas (CCA), the presence of bizarre nuclei (BN), tumour infiltrating-lymphocytes (TILs), peritumoral lymphocytes, MELF-type invasion (MELF), lymphovascular invasion (LVI), MMR protein and p53 expression, FIGO stage, adjuvant treatment, recurrence and status.

Results: Median age was 60.4 years. 31 patients were FIGO I-II and 10 FIGO III-IV stage. Median follow-up was 64 months. 36 patients are alive (35 without disease, 1 with disease), 2 died from disease (DFD) and 3 from unrelated causes.

35 cases were endometrioid carcinomas (EECs): 28 G3, 5 G1, 2 G2; 2 mixed carcinomas and 4 carcinosarcomas. 20 tumours showed IH, 4 CCA, 9 SA, 20 BN. 22 had LVI and 3 MELF. TILs were frequent.

8 cases were MMR-deficient, 7 p53-abnormal and 1 a multiple-classifier.

The most frequent pathogenic POLE mutations were: 26 V411L, 16 P286R and 4 A456P. The 2 patients who DFD showed non-pathogenic mutations.

Conclusion: POLE-mutated ECs are typically high grade EECs in which IH, increased TILs and BN are frequently observed. Abnormal p53 expression and/or loss of MMR protein expression in high grade tumours, does not exclude POLE mutations. Patients with pathogenic POLE mutations have a favourable prognosis, despite presenting advanced stage at diagnosis.

OFP-10-011

The morphological heterogeneity of fumarate hydratase-deficient leiomyoma: a single institutional experience

E. Bariani*, E. Piazzola, C. Di Pace, A. Caliò

*Department of Diagnostic and Public Health, Section of Pathology, University of Verona, Italy

Background & objectives: Fumarate hydratase (FH)-deficient leiomyoma is a distinct subtype of uterine leiomyoma occurring in sporadic and syndromic settings. Published studies reported a characteristic morphology although its sensitivity remains questionable.

Methods: 1298 uterine samples (biopsy and surgical specimens) were retrospectively found from a single academic institution's pathology database between January 2018 and December 2020 identifying sixteen FH-deficient leiomyomas in 14 women (1.08% of all samples; 1.2% of surgical specimens). We evaluated clinical and histological characteristics (evaluated from 1 to 8 slides per tumour, median=3), collecting data on cytological and architectural features.

Results: Median age was 43 years (from 29 to 54), most nulliparous(8/14). The average tumour size was 8 cm(from 0.7 to 12). In 9 patients, conventional leiomyomas were associated. None reported a family or personal history of hereditary leiomyomatosis and renal cell carcinoma syndrome. All patients were alive without disease. Grossly, 13 tumours were white whorled (two tumours were yellowish, one was spongy). Morphologically, the tumours were cellular(2), epithelioid(1), with remarkable bizarre nuclei(1), micro-macrocystic(2). Staghorn-shaped vessels were seen in 10, thick-wall vessels in 5, multiple micro-vessels in 6 tumours, frequently in combination. Only one tumour displayed an unremarkable vascular pattern. Prominent nucleoli were easily encountered in 5 tumours, in the remaining cases were pinpoint. Other focal features observed were palisading arrangement(3), inflammatory infiltrate(5), nuclear pseudo-inclusions(5), scattered eosinophilic cytoplasmic globules(10). Necrosis was absent in all cases.

Conclusion: Morphological distinct features of FH-deficient were observed in 6 tumours (37%). Most of the tumours resemble conventional leiomyomas at low magnification with focal and subtle histological features of FH-deficiency. The vascular pattern (staghorn-shaped, thick-wall, and micro-vessels) is the most reliable finding.

OFP-10-012

Investigation of progestin-induced changes in the endometrial transcriptome: Implications for personalized medicine in low-grade endometrial neoplastic lesions

B. Djordjevic*, E. Olkhov-Mitsel, J. Mirkovic, Y. Amemiya, A. Seth

*Sunnybrook Health Sciences Centre, University of Toronto, Canada

Background & objectives: Mechanisms underlying resistance to progestin therapy in endometrial carcinoma (EC) are poorly understood. In this study, we characterized progestin-induced transcriptomic changes in neoplastic and non-neoplastic endometrium to distinguish physiological effects of progestin from predictive biomarkers unique to lesional treatment response.

Methods: We have previously examined the transcriptomic profile of low-grade endometrial neoplastic lesions (LGENLs) – atypical hyperplasias and FIGO grade1 ECs - that exhibited complete response (CR) to progestin therapy. In this study, Pre- and post- progestin treated biopsy samples of 4 patients with disordered proliferative and 4 with proliferative phase endometrium underwent whole transcriptome RNA sequencing of >20,000 human genes.

Results: Unsupervised analysis separated pre- and post-treatment non-neoplastic endometrium into 2 distinct clusters. Supervised analyses identified 2572 differentially expressed genes (P≤0.05, fold change≥2), which represent a molecular signature of progestin effect. Of these, 391 (15%) also exhibited progestin-induced changes in expression in CR LGENLs. Next, our analysis focused on 73 progesterone-related pathway genes. Interestingly, comparing the expression of these genes between non-neoplastic endometrium and LGENLs post-treatment identified only 1 common gene, FOXO1, a known marker of progestin response. Further, we found progestin-induced changes in expression of PTN were unique to CR LGENLs while changes in FOS, ADM, PIK3R3, PGR, PTGER2, CD38, TYMS, TLR2 and DSG2 expression were unique to non-neoplastic lesions.

Conclusion: Non-neoplastic endometrium exhibits a much wider spectrum of DEGs than CR LGENLs, both globally and when focusing on progesterone pathway genes, suggesting progestin response may be already impaired in LGENLs. Next, comparative analysis of transcriptomic features that would differentiate non-neoplastic endometrium, CR and non-responder LGENLs sampled prior to progestin therapy will be performed to search for predictive biomarkers.

Funding: This study was conducted with the support of the Ontario Institute for Cancer Research through funding provided by the Government of Ontario.

OFP-10-013

PD-L1 expression and mismatch repair status in endocervical clear cell carcinomas

P. Bulutay*, N. Haberal, Ö. Özen, N. Kapucuoğlu

*Istanbul, Koç University Hospital, Department of Pathology, Turkey

Background & objectives: Endocervical clear cell carcinoma (cCCC) is a rare tumour and resistant to conventional chemotherapy. PD-L1-expression is used as a predictive biomarker for immunotherapy. Mismatch-repair-deficiency is associated with the immunotherapy response. We evaluated PD-L1 expression and mismatch repair status in cCCCs.

Methods: Immunohistochemical staining for PD-L1 (SP263 clone) expression was performed on a tissue microarray of 14 cCCC cases (6 mm diameter two tissue cores from each case). Expression was scored in both the tumour and tumour-infiltrating immune cells as follows; negative (<1%), low (1-4%), intermediate (5-50%), and extensive (>50%) staining. Furthermore, tumoral mismatch repair status (MLH1, MSH2, MSH6, PMS1) was evaluated.

Results: PD-L1 expression, either tumoral or tumour-infiltrating immune cells, was present in 71.4% (10/14) of cCCCs. Most of the positive cases showed PD-L1 expression in ≤50% (8/10) of the tumoral cells. Almost all cases were accompanied by intermediate or low-level immune cell infiltration. PD-L1 expression in immune cells was present in 61.5% (8/13) of the cases. Extensive PD-L1 expression was seen in 2 cases. They also had mismatch repair deficiency (MSH2 loss, MLH1-PMS2 loss). Overall mismatch repair deficiency was seen in 35.7% (5/14) of the cases. PD-L1 expression was observed at all mismatch repair deficient cases except one (4/5). However, 60% of the PD-L1 positive cases were remained mismatch repair intact.

Conclusion: The prevalence in endocervical CCC is still underinvestigated. We evaluated PD-L1 expression in 14 endocervical CCCs and correlated with the mismatch repair status. We herein demonstrate that some degree of tumoral and peritumoral immune cell PD-L1 expression is present in endocervical CCCs. This finding suggests a role for further investigation of anti-PD-L1/PD-1 immunotherapies in the treatment of PD-L1-positive cCCCs. Moreover, mismatch repair deficiency may support this finding. Further studies in larger series are needed to confirm our findings.

OFP-10-014

Lynch Syndrome screening algorithm in endometrial carcinoma can be improved

C. Bartosch*, B. Oliveira, J. Costa, P. Lopes, C. Santos, A. Peixoto, C. Pinto, C. Jeronimo

*Portuguese Oncology Institute of Porto (IPO-P), Portugal

Background & objectives: Lynch syndrome(LS) screening in endometrial carcinoma(EC) starts with mismatch repair protein(MMR) immunoexpression, followed by MLH1 methylation in ECs showing MLH1/PMS2 expression loss. We aim to identify points of improvement in LS screening algorithm, focusing on MMR immunoexpression patterns and second allele MLH1 methylation.

Methods: All consecutive patients diagnosed with EC showing altered MLH1 protein expression were selected (2009-2020, n=55). Clinical files and immunohistochemistry slides were reviewed. DNA was extracted from FFPE samples, and subjected both to bisulfite modification followed by amplification by quantitative methylation-specific PCR (qMSP), and to Methylation-Specific Multiplex Ligation-Dependent Probe Amplification (MS-MLPA).

Results: We were able to distinguish three MLH1 methylation groups: the first, with patients whose tumours do not have methylation in any alleles (n=20), the second with patients whose tumours had partial methylation (n=14), most probably in only one allele, and lastly, patients whose tumour had methylation in both alleles (n=21). The vast majority of patients that proceeded to germline testing belong to the first group, and patients on the other groups were rarely tested. Immunohistochemistry study showed that MLH1 expression can be completely lost (n=44) but also presented as subclonal loss (n=6) and decreased immunoexpression (n=5). All these patterns of immunoexpression can be associated with LS.

Conclusion: LS screening in EC patients is highly dependent of immunohistochemistry and MLH1 methylation results. All altered immunohistochemistry patterns should be taken into account. Patients with partial MLH1 methylation, most probably have only one methylated allele, as a putative second hit, and thus may be considered for LS germline testing. By including these patients in LS screening, we expect a small increase in the number of patients diagnosed with LS; but importantly, identifying a patient with LS, means identifying a family with LS.

OFP-10-015

Cytology-histology correlation in HPV-related patients based on the recent American Society of Cytopathology guidelines (2017)

A. Asaturova*, D. Attoeva, N. Nazarova, D. Dobrovolskaya, A. Shilyaev, G. Bayramova

*FSBI "National Medical Research Center for Obstetrics, Gynecology and Perinatology after V.I. Kulakov" Ministry of Healthcare Russian Federation, Russia

Background & objectives: The aim of the study was to conduct a retrospective comparative analysis of the cytological and histological diagnoses in women with cervical pathology associated with the human papillomavirus (HPV).

Methods: A retrospective review was conducted for cervical biopsies with their corresponding liquid-based cervical smears (SurePath) over a 2-year period (2018-2019). According to ASC guidelines, a discrepancy assessment grid was prepared. Major cytology-histology discordance was defined as a diagnosis of high-grade squamous intraepithelial lesion (HSIL) or CIN2+ in one of the tests with negative result in the other.

Results: We analysed 3 groups based on the results of studies: the 1st group included patients with complete coincidence of cytological and histological diagnoses. The 2nd group - minor discrepancies, the 3rd group - significant discrepancies. Of the 415 cervical biopsies with corresponding Papanicolaou liquid-based smear, cytology-histology agreement was noted in 194 (46.74%). Major discordance was observed in 29 cases (6.9%), while 4.8% cases of cytological result "NILM" corresponded to the histological diagnosis of HSIL, and 2.1% of cases with a cytological findings of HSIL, a histological findings was diagnosed with "benign" (chronic cervicitis). The minor discrepancies was 192 (46%).

Conclusion: We suppose that ASC guideline helps to standardise the conduct of cervical cytology-histology correlation internationally. Our comparative analysis showed that in all groups there were cases of underdiagnosis and overdiagnosis in cytological examination, however, there were few observations in which management of the treatment changed significantly due to different cytological and histological diagnoses (6.9%).

Funding: grant RFFI 21-315-70048

OFP-10-016

Malignant mixed ovarian germ cell tumours: a 9 years’ experience from a tertiary referral centre

I. Arora*, N. Sarwar, M. Seckl, B. Kaur

*Imperial College Healthcare NHS Trust, United Kingdom

Background & objectives: Malignant mixed germ cell tumours (MMGCT) of the ovary are relatively rare neoplasms accounting for less than 5% of all ovarian cancers. We evaluated the incidence, clinico-pathological characteristics, clinical outcome of MMGCT at our centre and reviewed the existing literature.

Methods: Twenty-three cases of MMGCT were identified among 996 cases of germ cell tumours (GCT) treated at our institute from 2012 -2020. Clinical data including demographics, stage, type of surgery, chemotherapy regimens, tumour marker levels, menstrual functions, fertility, and outcome were collected for each patient from medical records and pathology reports.

Results: Ovarian MMGCT accounted for 2.3% of all GCT. Median age was 27 years (range, 17-42). Most common presenting symptoms were abdominal mass and pain (81%). Average tumour size was 16 cm (range, 6.8-30). Majority were stage I-II tumours (81%). Most frequent histological combination was yolk sac tumour and immature teratoma seen in 12 patients (52%). Seventeen (74%) patients underwent complete surgical staging. Fifteen (65%) received post-operative chemotherapy. Only one patient received neo-adjuvant chemotherapy. During a median follow-up period of 32.4 months, 2 patients had recurrence. Eleven patients (61%) developed chemotherapy complications. Median overall survival was 28.2 months. No adverse prognostic variables were identified, and 90% patients had good overall survival.

Conclusion: MMGCT are rare tumours affecting adolescent females of reproductive age, therefore fertility preservation and long-term survival is extremely important. Majority of these tumours are diagnosed at an early stage, have a good response to the standard treatment regimens and a good clinical outcome. However, due to the rarity of the disease, there is a clear need for more studies to better identify prognostic factors that will further improve the clinical outcome of patients with advanced/relapsed disease.

OFP-10-017

Association between immunohistochemistry in endometrial hysteroscopic biopsies and pregnancy within six months

D. Andrade*, V. Chiavelli, M. Stiepcich

*Grupo Fleury, Brazil

Background & objectives: Chronic endometritis is a common disease associated with infertility. Although the histopathological and immunohistochemical evaluation are considered essential for its diagnosis, the diagnostic criteria or sampling recommendations are not yet defined.

Methods: This was a retrospective cohort evaluating women with infertility submitted to hysteroscopy with endometrial biopsy in the Fleury Group, in Brazil, from 2012-2020. Variables of interest included: size of the biopsy specimen, presence, and quantification of CD56- and CD138-positive cells in the endometrial stroma, and evidence of pregnancy within six months from the biopsy (assessed either by β-HCG or pelvic ultrasound).

Results: We included 696 patients, with median age of 37-years and median biopsy size of 5mm. CD56-positive and CD138-positive cells were detected in 97.7% and 26.7% of the samples, respectively. Samples with CD138-positive cells presented a higher quantification of CD56-positive cells in the stroma (median[25th-75th percentiles]: 20%[14.25-25%] vs. 15%[10-25%]; p:0.013). Pregnancy testing was performed in 202 patients, with positive results in 112. Patients with positive testing presented more frequently CD138-positive cells in the endometrial stroma (32.1% vs. 17.8%, p:0.020). Finally, a multivariate analysis demonstrated that the presence of CD138-positive cells was an independent predictive factor for pregnancy (p:0.018), controlled by the phases of the endometrial cycle, CD56-positivity, or size of the biopsy.

Conclusion: We found that the presence of CD138-positive cells was associated with pregnancy within six months, regardless of the biopsy size, indicating the impact of endometritis assessment even in hysteroscopic biopsies.

OFP-10-018

PD-L1 expression in endometrial carcinomas: which tumours are more likely to be PD-L1–positive?

J.Z. Amarin, R. Mansour, S. Al-Ghnimat, I. Lataifeh, I. Jaradat, G. Abdeen, L. Otay, Q. Shatnawi, A. Abu Sheikha, A. Dayyat, F. Abuhijla, M. El Khaldi, M. Al-Hussaini*

*King Hussein Cancer Center, Jordan

Background & objectives: Many promising clinical trials of anti–PD-1/PD-L1 monoclonal antibodies for endometrial cancer are ongoing. Patients with endometrial carcinomas that express PD-L1 may respond better to immunotherapy. Our aim was to investigate the differential characteristics of PD-L1–positive endometrial carcinomas.

Methods: We reviewed records of patients with endometrial carcinomas who were managed at the King Hussein Cancer Center (2007–2016) and performed immunohistochemistry for MLH1, PMS2, MSH2, MSH6, p53, and PD-L1. We stratified patients according to tumoral PD-L1 expression (< 1% or ≥ 1%), described the clinical and tumoral characteristics of the strata, and tested associations using Pearson’s χ2 test.

Results: We included 231 women. According to Bokhman’s classification, 156 tumours (67.5%) were type I and 75 (32.5%) were type II. Of 156 endometrioid carcinomas, 52 (33.3%) were FIGO grade I, 83 (53.2%) were grade II, and 21 (13.5%) were grade III. Overall, 89 cases (38.5%) were MMR-deficient. PD-L1 was expressed in 49 cases (21.2%) and was associated with MLH1/PMS2 deficiency (p = 0.044) but not MSH2/MSH6 deficiency (p = 0.59). p53 was mutant in 106 cases (46.5%) and mutation was associated with MMR proficiency (p < 0.001) but not PD-L1 expression (p = 0.78). In patients with endometrioid carcinomas, PD-L1 expression was associated with FIGO grade (p = 0.008).

Conclusion: In conclusion, tumours with MLH1/PMS2 loss and high-grade endometrial carcinomas were more likely to express PD-L1 in tumour cells. The presence of either characteristic may signal a higher likelihood of a favourable response should immunotherapy be administered.

OFP-11 | Haematopathology

OFP-11-001

Clinicopathological implications of RHOA mutations in angioimmunoblastic T-cell lymphoma: a meta-analysis

T. Ngo*, P. Nguyen, N. Tran, T. Nguyen, D. Lai, H. Vuong

*Pham Ngoc Thach University of Medicine, Vietnam

Background & objectives: Studies have shown that RHOA mutations play a crucial role in angioimmunoblastic T-cell lymphoma (AITL) pathogenesis. We aimed to pool data from these studies to compare clinicopathological features between the RHOA mutant and RHOA wild-type groups in the AITL population.

Methods: We searched PubMed and Web of Science for the keywords "RHOA AND lymphoma" and selected only studies reporting the clinical significance of RHOA mutations in AITL. We calculated the odds ratios (OR) or the mean difference with 95% confidence intervals (CI), using a random-effect model.

Results: Our pooled results showed a significant association between RHOA mutations and a T-follicular helper cell (TFH) phenotype, especially CD10 (OR=5.16; 95% CI: 2.32-11.46), IDH2 mutations (OR=10.70; 95% CI: 4.22 - 27.15), and TET2 mutations (OR=7.03; 95% CI: 2.14 - 23.12). Although DNMT3A together with TET2 and IDH2 mutations are epigenetic gene alterations, we found an insignificant association between RHOA and DNMT3A mutations (OR=1.72; 95% CI: 0.73 - 4.05). No significant associations of RHOA mutations with other clinicopathological features and overall survival were found.

Conclusion: RHOA mutations are strongly correlated with a TFH phenotype and epigenetic mutations such as TET2 and IDH2. Further studies with large AITL samples should be conducted to validate the relationship of TET2, DNMT3A, and RHOA co-mutations.

OFP-11-002

Clinicopathologic study of mantle cell lymphoma with EBV infection

X. Li*, Y. Li

*Chongqing University Cancer Hospital, China

Background & objectives: Mantle cell lymphoma (MCL) with EB virus (EBV) infectionare rarely reported. Herein, we report the largest series of analyses of the prevalence and clinicopathological features of mantle cell lymphoma with EBV infection.

Methods: 138cases of MCL diagnosed in the first affiliated Hospital of Chongqing Medical University and Chongqing University Cancer Hospital from January 2014 to November 2019 were collected retrospectively. Cases with EBV infection were screened by EBER ISH, then double labelling of EBER(ISH) and CD79α(IHC) was performed, clinical and pathological data were analysed.

Results: EBER ISH showed that there were 8 cases of MCL with EBV infection (the infection rate was 5.8%), and all of them were non-neoplastic bystander cells with positive EBV and there was no expression of LMP1 and EBNA2. All MCL with EBV infection have no abnormal immune function and without other lymphomas, and their histopathological morphology showed classic MCL. MCL with EBV infection and MCL without EBV infection have statistically significant differences in LDH, anaemia status, and MIPI grouping (P=0.008; P=0.02; P=0.001; P=0.011). The differences were not statistically significant between two groups in age, sex ratio, clinical manifestations and immunohistochemical phenotypes.

Conclusion: The incidence of MCL with EBV infection is low, and its clinicopathological features are similar to those of MCL without EBV infection. This study shows that the cells infected by EBV in MCL are background cells rather than tumour cells, which is different from previous studies, indicating that tumour cells in MCL may not prone to EBV infection.

OFP-11-003

Lymph node biopsies of primary immunodeficiency disorders: our experience in a tertiary hospital

E. Garcia Fernandez*, P. Puente Lopez, G. Olmedilla Arregui, A. Robles Marhuenda, E. Lopez Granados

*La Paz University Hospital, Spain

Background & objectives: There are more than 100 primary immunodeficiency disorders, our aim was to review the lymph node biopsies diagnosed since 2016. We collected all the clinical information from our database, molecular, immunohistochemistry studies and reviewed all the slides from each case.

Methods: We found nine patients, 6 women and 3 men. Five cases had variable common immunodeficiency (VCI), with a mean age of 43 (37-60 years-old). The other 4 cases were a Chediak-Higashi syndrome (CH); an autoimmune lymphoproliferative syndrome (ALPS), a PI3K primary immunodeficiency and a humoral immunodeficiency not yet defined. These cases were all children with ages from 2 to 12.

Results: At the lymph node biopsy the VCI cases had two type of patterns, 3 cases had non-necrotizing granulomas and 2 cases follicular hyperplasia with ill-defined germinal centres. 1 patient had a TCR clone with no histology of lymphoma.

The patient with CH had a T cell atypical population with a TCR clone. She had a bone marrow transplant to treat her immunodeficiency. The case of ALPS had an increase of doble negative T cell lymphocytes, the PI3K had a follicular hyperplasia positive for Epstein-Barr virus (EBV) and cytomegalovirus. The last case was diagnosed of lymphoproliferative disorder EBV associated, clonal for IgH and was treated with Rituximab.

Conclusion: We present a series of cases of primary immunodeficiency disorders, with a variable and complex histology. Of the nine patients only 1 patient was diagnosed as a B cell lymphoma. To diagnose, treat and follow up these patients it´s necessary to have a multidisciplinary group of physicians like at our centre.

OFP-11-004

Idiopathic multicentric Castleman disease - differential diagnosis based on histopathological features

L. Rodríguez Merino*, I. Hernández Alconchel, S. Montes Moreno

*Servicio de Anatomia Patologica, Laboratorio de Hematopatologia Traslacional, HUMV/IDIVAL, Spain

Background & objectives: International Consensus Diagnostic Criteria for iMCD include lymph node Castleman Disease histopathological features as major criteria. Our aim was apply those criteria in a series of 27 cases with a previous pathological diagnosis of Plasma Cell type Castleman Disease (CD).

Methods: A retrospective series of 7 cases was analysed. Clinical and laboratory criteria were collected and histopathological features (germinal centre hyperplasia/regression, plasmacytosis, hypervascularity and follicular dendritic cell prominence) were graded in the available lymph node samples. Immunohistochemistry with antibodies against CD20, CD3, CD138, HHV-8, Ig isotype (IgG, IgG4, IgA, IgM, IgD), kappa, lambda was performed in all cases.

Results: 15 out of 27 (55%) cases were HHV-8+, 7 /26%) plasma cell neoplasia (PCN)/POEMS-related CD and 5 (19%) were iMCD. The iMCD cases showed more frequently reactive germinal centres whereas the HHV-8+ showed higher degree of hypervascularization. Clusters of IgM+lambda+ cells were identified in all HHV-8+ cases. Lambda plasma cells were identified in 3 out of 7 cases (43%) of PCN/POEMS-related CD. All 5 cases of iMCD were IgG+ and polytypic. The median number of IgG4+ cells was 14. 5 out of 23 cases (22%) had 30 or more IgG4 positive cells but none had >100 IgG4+ cells. The IgG4/IgG ratio was below 0.4 in all cases.

Conclusion: HHV-8 CD and PCN/POEMS-related CD are the major mimickers of iMCD in lymph node biopsies with plasma cell type CD features. High grade of plasmocytosis is a common feature but the presence of reactive germinal centres may support a diagnosis of iMCD. Monotypic plasma cells are found in only 43% of PCN/POEMS related cases. A dim increase in IgG4+ plasma cells is found occasionally in CD but neither the histopathology nor the IgG4/IgG ratio fit with IgG4 related disease criteria.

OFP-12 | Head & Neck Pathology

OFP-12-001

Mandibular invasion in OSCC is associated with osteoclast count and expression of its regulating proteins

W. de Kort*, W. Haakma, R. van Es, E. Driehuis, M. Gansevoort, S. Willems

*Department of Pathology and Medical Biology, University Medical Center Groningen, The Netherlands

Background & objectives: Oral squamous cell carcinoma(OSCC) frequently invades the mandible. Osteoclast activation via RANKL/OPG/RANK plays an important role in bone-invasion. The exact mechanism of bone-invasion remains unclear. We elucidate the role of osteoclasts and RANKL/OPG/RANK in the development of bone-invasion in OSCC.

Methods: OSCC-patients treated with resection were included and divided in three groups; Non-invasion (NI-group), erosion (E-group) and bone-invasion (I-group). Tissue sections were stained with CathepsineK (for counting osteoclasts), RANKL, OPG and RANK. Staining intensity was scored in tumour-front, tumour-center, backside of tumour and normal mucosa. A qPCR was executed for RANKL, OPG and RANK in five head and neck SCC organoids.

Results: The mean number of osteoclasts in CathepsinK stained sections was 3.09 in the NI-group, 6.15 in the E-group and 10.58 in the I-group.

Compared to normal mucosa, the expression in all tumour regions was higher for RANKL, in most of tumour regions for OPG and not higher for RANK.

RANKL-expression in the tumour-front was higher than expression in the backside of the tumour in the I-group. RANK-expression in the tumour-front and the tumour-center was higher than expression in the backside of the tumour in all groups.

qPCR showed a 20-35x higher RANKL expression in 3 out of 5 tumour organoid samples compared to a normal squamous cell organoid line.

Conclusion: The number of osteoclasts and their regulating proteins (RANK, RANKL and OPG) differ between OSCC patients with and without bone-invasion. Our data suggest that tumour cells induce bone-invasion in OSCC patients by stimulating osteoclast activation by regulating the production of RANK, RANKL, and OPG proteins.

OFP-12-002

The clinical impact of PROX-1 expression in salivary gland tumours

A. Pergaris*, N. Georgantzoglou, P. Sarantis, G. Tsourouflis, D. Goutas, J. Klijanienko, S. Theocharis

*First Department of Pathology, Medical School, National and Kapodistrian University of Athens, Athens, Greece, Greece

Background & objectives: Salivary gland tumours (SGTs) encompass benign to highly malignant entities. The human PROX-1 gene belonging to the homeobox transcription factor family, exerts lymphangiogenic, angiogenic and possibly carcinogenic properties. The clinical significance of PROX-1 expression was examined in SGTs.

Methods: PROX-1 protein expression was assessed immunohistochemically in 48 formalin fixed, paraffin embedded SGT tissue specimens (30 benign and 18 malignant). PROX-1 positivity was correlated with benign and malignant state, other clinicopathological parameters and patients’ survival in malignant SGTs.

Results: PROX-1 positive immunohistochemical expression (nuclear, cytoplasmic or nuclear and cytoplasmic) was noted in 27 out of 30 (90%) benign and 11 out of 18 (61%) malignant SGT cases, respectively. PROX-1 positivity and cytoplasmic pattern of staining was more frequently noted in benign versus malignant SGT cases (p=0.017 and 0.05, respectively). On the other hand, PROX-1 positivity in malignant SGT cases was correlated with low grade of differentiation (p=0.048). The cytoplasmic pattern of PROX-1 immunostaining was also linked to high histological grade, although non-significantly (p=0.056). In malignant SGT cases, a correlation between PROX-1 positivity and poor overall patients’ survival, at a non-significant level though, was noted (p=0.084).

Conclusion: Our results suggest a link between PROX-1 expression and carcinogenesis in the salivary glands, designating it as a possible diagnostic and prognostic biomarker. In addition, suppression of lymph- and angiogenesis through PROX-1 targeting should be of great importance as a potential future therapeutic strategy in malignant SGTs.

OFP-12-003

Clinicopathological characterisation of salivary duct carcinoma with rhabdoid features (SDCRF): Immunohistochemical and genetic analyses of 19 cases

K. Kusafuka*, H. Yamada, K. Ishino, S. Baba, Y. Arai, K. Yamanegi, H. Iwai, S. Yamanaka, T. Daa, J. Fukuoka, M. Yasuda, H. Sugimura

*Department of Pathology, Shizuoka General Hospital, Japan

Background & objectives: Salivary duct carcinoma (SDC) has several histological subtypes. We established “SDC with rhabdoid features (SDCRF)” as a new entity, and it showed no or aberrant expression of cell-cell adhesion molecules. We aim to elucidate the clinicopathological features of SDCRF.

Methods: We collected 417 cases of SDC as Japanese cohort, and extracted the cases with rhabdoid features(RF). We immunostained sections for AR, HER2, EGFR, CK5/6, Ki-67, E-cadherin and beta-catenin, and also examined CDH1 gene, genetically. According to Takase classification, we subclassified into apocrine A, apocrine B, apocrine-HER2, HER2-enriched, and double-negative subtypes. We analysed the outcomes of SDCRF, compared with conventional SDC.

Results: Nineteen cases of SDCRF (4.6%) were extracted from our cohort. The mean age was 67-year-old (range; 36~86-year-old) with male predilection. The primary site was mainly parotid gland (14 cases). pStage 0-I, II, III, and IV were 3, 1, 2, and 11 cases, respectively. Eight cases died of disease, whereas 8 cases harboured distant metastases relapse. One, 11, 5, and 2 case belonged to apocrine A, apocrine B, apocrine-HER2, and HER2-enriched subtype, respectively. No or aberrant expression of E-cadherin//beta-catenin were observed in 12//9 cases or 4//7 cases, respectively. All cases never showed co-expression of cytokeratin and vimentin. One nonsense mutation, six missense mutations and one insertion were detected in CDH1 gene.

Conclusion: SDCRF was previously diagnosed as “poorly differentiated” SDC, but all cases showed the common histology with RF. From no co-expression for cytokeratin and vimentin, they were not "true" rhabdoid cells. SDCRF harboured non-/less-cohesive cell-cell adhesion. Therefore, SDCRF indicated distant metastases relapse (8/19) rather than loco-regional relapse (2/19). Although the proportion of the molecular subtypes of SDCRF were not so different from that of conventional SDC, SDCRF indicated worse outcomes than the latter, due to frequently distant metastases relapse.

Funding: Medical Research Support Project of Shizuoka Prefectural Hospital Organization in 2019 (to K.K.) and AMED (20ck0106554) (to H.S.) and SRF (to H.S.).

OFP-12-004

Clinicopathological and genetic analyses of sinonasal glomangiopericytoma (SN-GAP): multi-institutional retrospective study on beta-catenin and CTNNB1 gene

K. Kusafuka*, S. Baba, M. Nagase, J. Itakura, Y. Otsuki, H. Takahashi, S. Yamanaka, M. Hamada, M. Yasuda, T. Iwasaki, M. Suzuki

*Department of Pathology, Shizuoka General Hospital, Japan

Background & objectives: Sinonasal glomangiopericytoma (SN-GAP) was previously called “hemangiopericytoma (HPC)”, “solitary fibrous tumour (SFT)”, or "glomus tumour (GT)" of the sinonasal cavity. This tumour is very rare but an independent entity. We aim to elucidate the clinicopathological and genetic features of SN-GAP.

Methods: We collected “GAP”, “HPC”, “SFT” and "GT" cases from a pathology file of our institutions during 2000-2020 and from a set of consultation files (K.K.), and re-estimated them, histologically and immunohistochemically. Some cases were examined genetically for CTNNB1 gene, using PCR-direct sequencing method. We compared SN-GAP with other sinonasal spindle cell neoplasms, such as SFT or GT.

Results: Four cases were re-diagnosed as “SN-GAP”, with female predilection. Histologically, the tumours consisted of compactly fascicular proliferation of short spindle-shaped myoid cells with mild atypia and often showed perivascular growth pattern with staghorn-like blood vessels. There was no evidence of necrosis nor anaplasia. Immunohistochemically, the tumour cells were positive for vimentin, alpha-smooth muscle actin, BCL-2, factor XIIIa and cyclin D1, but negative for cytokeratin, desmin, CD34, STAT6, and S-100 protein. Ki-67 labelling index was approximately 2-13%. The nuclear localization of beta-catenin was observed in all cases. All cases, which could be examined, indicated the missense mutations [codon110C>G(p.Ser37Cys); codon121A>G(p.Thr41Ala)] in exon 3 of CTNNB1gene. The outcome was good in SN-GAP cases.

Conclusion: SN-GAP indicated the nuclear localization of beta-catenin, and it was induced from the missense mutation in exon 3 of CTNNB1 gene, which codes beta-catenin. The combination of the immunostaining for beta-catenin and the molecular examination for CTNNB1 gene mutation are very specific and useful for differential diagnosis of SN-GAP from other spindle cell neoplasms of sinonasal cavity; especially, monophasic fibrous synovial sarcoma, GT, SFT, low-grade myofibroblastic sarcoma and biphenotypic sinonasal sarcoma.

OFP-12-005

Dyshormonogenetic goiter: a study of 4 cases

A. Bchir*, S. Mestiri, M. Belakhadher, T. Tlili, S. Chaieb, N. Abdessayed, B. Sriha, M. Mokni

*Department of Pathology, Farhat Hached Hospital, Tunisia

Background & objectives: Dyshormonogenetic goiter (DG) is a rare inherited disease. It is a thyroid enlargement due to defects in thyroid hormones synthesis. The aim of our study is to highlight the clinico-pathological characteristics of dyshormonogenetic goiter.

Methods: We describe 4 patients with dyshormonogenetic goiter. Data were obtained from the files of Ear Nose Throat Department and Pathology Department of Farhat Hached Hospital of Sousse, Tunisia.

Results: There were 2 male and 2 female patients. The average age was 16 years. Consanguinity and congenital hypothyroidism has been reported in all patients. Neck swelling was the complaining symptom in all cases. On macroscopic examination, the mean size was 7 cm. Histologically; it was a multinodular goiter without any normal thyroid tissue. Nodules were hypercellular with a solid or microfollicular patterns. Colloid is minimal to absent. The follicular cells exhibit marked nuclear atypia with bizarre nuclei. These nuclear atypia is more common in internodular tissue. The nodules are entrapped with extensive fibrosis which can simulate malignancy. 2 patients underwent total thyroidectomy and the 2 others had partial thyroidectomy.

Conclusion: Dyshormonogenetic goiter is an autosomal recessive disease. It is a benign thyroid hyperplasia due to hereditary defects in hormone synthesis. It is the second cause of congenital hypothyroidism after thyroid dysgenesis. This disease affects more female than male. The mean age of patients is 16 years. Histologically, this tumour is a multinodular goiterwith markedly cellular parenchyma and extensive internodular fibrosis. Rare cases of thyroid cancers related to DG have been reported. Treatment is based on surgery and L-thyroxin.

OFP-12-006

Warthin-like mucoepidermoid carcinoma - a morphologic spectrum: report of 3 cases with histological and cytological findings and review of the literature

K. Basak*, C. Aydin Mericoz, P. Fırat

*University of Health Sciences, Kartal Dr.Lütfi Kırdar City Hospital, Department of Pathology, Istanbul, Turkey

Background & objectives: Mucoepidermoid carcinoma (MEC) showing Warthin's Tumour (WT) like features is a low-grade malignancy which should be differentiated from WT. Morphological features may be distinctly different in each case causing diagnostic difficulties. Three cases are discussed in this presentation.

Methods: One case was a 16 year-old female, the other two cases were 27 and 53 year-old males. All presented with a mass in the parotid gland which went to parotidectomy and all had pre-operative fine needle aspirations. On histopathological examination first case was initially interpreted as WT, the other two were morphologically consistent with low grade MEC with WT-like features.

Results: Prominent lymphoid stroma and cystic pattern was the character of these tumours. One case had the classical WT appearance with some mucinous and squamous metaplasia which could only be interpreted as MEC after the detection of MAML2 rearrangement by FISH. The other two showed either focal or relatively diffuse usual low-grade MEC findings, one of these cases was also confirmed by MAML2 rearrangement. Cytologically one case was interpreted as non-informative due to presence of cyst fluid only, one case was suggestive of WT, only one case was found to be suspicious for MEC which contained squamous and goblet cells on a mucoid background. Cytological and histopathological features revealed a spectrum.

Conclusion: Differentiating WT-like MECs from ordinary WTs may be challenging. On one end of the spectrum they may look very much like WT, on the other end, even though usual MEC features are present, still WT-like appearance may pose diagnostic difficulty. Showing MAML2 rearrangement in these cases is very helpful. Presence of mucinous and squamous cells in an otherwise WT-like looking tumour should be alarming for MEC and if possible, each case should be analysed for MAML2 rearrangement.

OFP-12-007

Deep proteomic profiling reveals two major subgroups in the extracellular matrix of salivary gland carcinomas

C. Arolt*, F. Hoffmann, L. Nachtsheim, P. Wolber, O. Guntinas-Lichius, R. Büttner, F. von Eggeling, A. Quaas, J.P. Klußmann

*Institute of Pathology, Medical Faculty, University of Cologne, Germany

Background & objectives: The extracellular matrix (ECM) is an integral component of the tumour microenvironment. As the ECM composition of salivary gland adenocarcinomas (SGC) has not yet been addressed, we set out to discover ECM profiles and putative therapeutic targets.

Methods: Using liquid chromatography–mass spectrometry (LC-MS), we quantitatively analysed the ECM proteins of 25 normal tissue samples and 89 primary SGC, encompassing the eight most prevalent tumour types. Among a total of 6478 unique proteins, we identified 329 ECM components which were subsequently analysed.

Results: All tumours exhibited a highly dysregulated ECM with a mean of 166.5 differentially expressed proteins per entity. PCA and hierarchical clustering revealed two clusters of carcinomas, either with (MYO) or without myoepithelial differentiation (non-MYO; purity: 100%, 93.75%). To asses whether a machine learning algorithm could detect MYO and non-MYO based on ECM expression, we trained an elastic net model which predicted tumour differentiation with an error rate of 3% (area-under-the-curve: 0.996). While MYO exhibited a higher fraction of upregulated collagens and glycoproteins, non-MYO displayed a higher fraction of upregulated secreted factors. We identified several ECM components known to promote tumour invasion, progression and chemoresistance, thus representing putative therapeutic targets.

Conclusion: Using machine learning tools, we demonstrate for the first time that SGC can be categorised in two classes based on their ECM expression. Tumours with and without myoepithelial differentiation exhibit dramatic differences regarding the ECM composition. Also, using highly sensitive proteomic profiling we identify several putative therapeutic targets in the ECM of SGC. Thus, our work contributes to the final goal of a personalised therapy for SGC.

Funding: The presenting author is a fellow of the Else Kröner-Fresenius Forschungskolleg, Cologne.

OFP-12-008

Clinicopathological correlation of transoral robotic head and neck cancer surgery

A. Ali*, M. Kadri, M. Kiakou

*Broomfield Hospital, United Kingdom

Background & objectives: Transoral robotic surgery (TORS) has revolutionised head and neck cancer surgery including both diagnostic and therapeutic work. In this study we access the correlation between the depth of resection, volume of resection, post-operative pain level and length of stay (LOS).

Methods: A retrospective cohort study in a Head and Neck Cancer hub. All 26 patients included had either diagnostic or therapeutic TORS at our unit. The procedures were performed using the Da Vinci Si Surgical System. Histological data included: specimen dimensions and volume, presence of malignancy, depth of tumour, depth of resection. Patient-reported pain score was recorded.

Results: The depth of muscle resection had a positive correlation (r=0.264) with the LOS, this was not statistically significant (p=0.224). Similarly, the volume of resection was positively correlated to the LOS (r=0.129), this was not significant (p=0.529). Multivariate analysis using types of procedure, depth of resection and volume of resection as independent variables showed these variables not to have significant effect on the LOS.

Conclusion: The current study’s hypothesis was that the extent (depth and volume and resection) of oropharyngeal resection is directly proportional to the level of post-operative pain. Interestingly however, our study showed that the depth of muscle resection did not affect the post-operative pain level. Another interesting point was a weak positive correlation between the volume of resection and pain, patient who had who had both tonsillectomy and Tongue Base Mucosectomy (largest resection volume) reported the least pain in our cohort.

OFP-13 | History of Pathology

OFP-13-001

Who was Arthur Carleton Crooke? A historical research after diagnosing a rare tumour

C. Pontinha*, M. Varela dos Santos, M. Mafra

*Central Lisbon University Hospital Centre, Portugal

Background & objectives: 36-year-old man admitted to Emergency Department with acute heart faillure. The MRI revealed a selar mass and the histopathological diagnosis of Crooke cell adenoma. The main objective of this research is to find out who first described this entity.

Methods: Bibliographic research was performed at PubMed using the terms "Crooke cell" and "Crooke cell adenoma". Articles that most emphasized the original description were selected.

Results: According to Bettendorf G, it was Herbert Evans, Harvey Cushing and Dorothy Russel who encouraged Arthur C. Crooke (1905-1990) to study pituitary histology at the beginning of his career. Crooke's hyaline change, first described in 1936, represents an accumulation of microfilaments around the nucleus in corticotrophs in response to an excess of glucocorticoids. These cells are basophilic or amphophilic, PAS positive and show strong imunoreactivity for ACTH and CK CAM 5.2 in a juxtanuclear pattern. Despite Crooke's scientific work in the field of pituitary pathology, his obituary highlights an even bigger contribution to Medicine: the treatment of infertility with human gonadotrophins.

Conclusion: It was A.C. Crooke, a famous British endocrinologist, who first described 85 years ago a group of characteristic cellular alterations in the hypophysis of patients dying of Cushing's disease. According to the 4th edition of the WHO Blue Book, Crooke cell adenoma is the official terminology for these rare corticotrophic adenomas with these cellular alterations (largest case series of 36).

OFP-13-002

Evolution of gastric metaplasia definition and a meaning of the phenomenon in a historical perspective

M. Stepanchenko, S. Mozgovoi*, A. Kononov, E. Abrosimova

*Omsk State Medical University, Russia

Background & objectives: Metaplasia is the replacement of one differentiated somatic cell type with another differentiated somatic cell type in the same issue. Historically, the development of submissions about metaplasia (intestinal metaplasia) was accompanied by a significant meaning modification.

Methods: Content analysis through systematic review of publications (Embase) by using key words "stomach/gastric" AND "metaplasia" was carried out. Marked evolutionary modification of these terms was revealed to the present time. A comparative method and a substantial analysis of sources were used to clarify the meaning of this phenomenon.

Results: Basic aspects of terms modification were identified and designated: general biological approach, pathology and epidemiology based approach, association with stem cells and genetic regulation. Each period was associated with basic values and features of the development of medical knowledge. Expanding on earlier discussion that metaplasias can develop when mature cells dedifferentiate and proliferate the modern aspects of this process is discussed about contribution of huge number of associated factors and conditions such as UACL, pseudopyloric metaplasia, TFF3-associates metaplasia etc. There are numerous similarities between gastric and esophageal intestinal metaplasia,suggesting an idea that the mechanisms would be identical.

Conclusion: The main feature of metaplasia is changing in cellular identity associated with transcription factors that inhibit and/or maintain cellular characteristics. Improved surveillance of metaplasia might lead to cancer prevention. All elements in terminology system affect each other with the following changes of conceptual apparatus (metaplasia - transdifferentiation - epithelial-mesenchimal transition). It means changing not only the terminology itself, but significantly affects the assessment of the pathological process via modern definitions and ideas.

OFP-13-003

Tortuous vessels in a historical university museum

R. Henriques De Gouveia*, T. Ferreira, L. Carvalho

*INMLCF & FMUC & CHLO, Portugal

Background & objectives: Varicose Veins of the limbs, already referred to in Ebers papyrus (1550 B.C.), remain a major vascular nosologic problem. The authors intend to draw attention to the issue, using the resources of the "Museu de Anatomia Patológica" in Coimbra.

Methods: A retrospective study of the specimens - human liquid-fixed and dehydrated (dried), as well as wax and clay artificial models or other type - kept in the Pathology Museum was performed, concerning varices. Photographs of the specimens were taken and the literature was reviewed.

Results: Nine (n=9) specimens were represented: eight as liquid-fixed in glass containers and one case corresponding to a set of black-and-white pictures showing varices and varicose ulcers with pre-surgery and post-saphenectomy limbs representation.

Conclusion: Venous disease with multiple risk factors (from genetic predisposition to professional long-standing position), presents diverse macro and microscopic abnormalities and may complicate (ulcers, haemorrhage, thrombosis). Throughout centuries, various therapeutic measures were applied (from Wiseman boot, passing by saphenectomy, to modern non-surgical approaches). Yet, it remains a serious Public Health issue, worldwide. Historical XIXth century Museum of Anatomical Pathology (Faculty of Medicine-University of Coimbra) fulfil pedagogic mission, as internationally, by displaying such specimens, also included in pre-graduated and graduated teaching programs.

OFP-14 | Infectious Diseases Pathology

OFP-14-001

Lymphoid cells with Russell's bodies in the spleen of patients died from COVID-19

M. Bobrovskikh, A. Bobrovskikh, A. Filin*

*Voronezh State Medical University, Russia

Background & objectives: Lymphoid cells containing aggregated immunoglobulins in the form of Roussel's bodies have been described in a wide variety of diseases. With COVID-19 infection, this cellular response in the spleen is poorly understood, which makes this study relevant.

Methods: Autopsy material of 34 spleens from persons who died from COVID-19 in 2020 was examined. The material was obtained from 20 men and 14 women who died between the ages of 30 and 91. The duration of the illness ranged from 3 to 23 days. The material was stained with hematoxylin-eosin. Part of the material was stained with PAS.

Results: In the red pulp of the spleen, among the relatively rare cells of the lymphoid series, there are few lymphoid cells with Russell's bodies. Sometimes, with significant emptying of the red pulp, large cells with abundant cytoplasm of the "plasmablast" type and single large lymphoblastic cells with a bright pink cytoplasm of the "flaming" type of cells appear in the reticular stroma. According to our data, a comparatively similar morphological picture of changes in the spleen does not depend on gender, age of the deceased, duration of illness, background and concomitant diseases (such as type 2 diabetes mellitus, hepatosis, diffuse and macrofocal postinfarction cardiosclerosis).

Conclusion: The detection of lymphoid cells with Russell's bodies in the spleen of patients who died from COVID-19 indicates their participation in the pathogenesis of this infection as a morphological sign of progressive suppression of the immune system in an unfavorable course of the disease.

OFP-15 | IT in Pathology

OFP-15-001

Digital analysis of intratumoural heterogeneity reveals higher leucocytic infiltrate in VETC (Vessels Encapsulating Tumour Clusters) areas

F. Barzaghi, S. Kumar, F. Cananzi, S. Jaillon, M. Valeri, V. Quagliuolo, L. Ruspi, P. Colombo, P.A. Zucali, L. Di Tommaso, L. Terracciano, S. Renne*

*Humanitas University, Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, Rozzano, Italy

Background & objectives: VETC is metastatic mechanism that involves vessel remodeling and invasion; endothelial covering might also act as an immune-modulator. To investigate this possibility, we studied the VETC related intratumoural heterogeneity of the immune infiltrate.

Methods: We identified several VETC prevalent sarcomas (n=3 alveolar_soft-part_sarcomas(ASPS), n=2 de-differentiated_liposarcomas(DDLPS), n=2 other high-grade), to regularize the inference we included n=5 renal-cell_carcinomas(RCC). We trained an artificial-neural-network(ANN) to recognize VETC with CD34 immunohistochemistry. With a transformation matrix we assessed leucocytes density (automatically with CD45). We then compared VETC_positive and negative areas using a multilevel-hierarchical probabilistic model controlling for histology and case.

Results: Within the same tumour, the areas with VETC tend to have a higher density of leucocytes with a mean z-score of 0.07 Vs -0.24 in the VETC_negative_areas [with a 89% Compatibility Interval (CI) from -0.47 to 0.67 Vs -0.73 to 0.28 respectively]. This was also true across all the different histotypes: mean z-score in ASPS of VETC_positive_areas was 0.15 compared to -0.14 of VETC_negative_areas [CI (-0.45_0.73) Vs (-0.70_0.39)], in DDLPS VETC_positive_areas was 0.23 compared to -0.37 of VETC_negative_areas [CI (-0.42_0.92) Vs (-1.19_0.18)], and in RCC VETC_positive_areas was 0.17 compared to -0.04 of VETC_negative_areas [CI (-0.32_0.71) Vs (-0.59_0.49)].

Conclusion: VETC_positive_areas had –within the same tumour, the same host-response (patient) and also across different histologies– consistently an higher immune infiltrate. This finding will prompt an accurate characterization that might unravel potential sensitivity to drugs targeting the VETC and modulating the immune infiltrate. More generally, we dissected the tumour microenvironment heterogeneity automating the tasks of image annotation and positive cell detection, an approach that we anticipate to be easily scalable.

OFP-15-002

The impact of level 6 synoptic reporting system on turn-around-times in a surgical pathology laboratory of a tertiary cancer centre

S. Rane*, S. Yadav, A. Shah, B. Narahari, D. Yadav, S. Desai

*Tata Memorial Centre-ACTREC, HBNI, India

Background & objectives: TAT, a critical quality parameter in clinical laboratories, is affected by several pre-analytical, analytical and post-analytical processes. In this work, we highlight the importance and impact of data-driven IT systems, automation of data-recording, report generation processes on TAT.

Methods: We compared the TAT of reports generated in a level-6 synoptic reporting system (SRS) with that of a free-text platform (FTS). In SRS, organ and cancer specific forms were used with entries being made in customised forms with selections entered by pathologists. FTS entries were primarily by typists from paper records made by pathologists.

Results: TAT was calculated as days from sample receiving to report finalization. The median TAT for the FTS and SRS was 11 & 8 days respectively. The proportion of reports finalized within the defined TAT increased from 87% for the FTS to 93% in SRS. The most significant impact was noted in the proportion of reports finalized in 5 days (4% vs 20%), in 8 days (28% vs 50%) and 11 days (50% vs 75%) in FTS vs SRS respectively. Cases requiring decalcification also showed similar results. There was also reduction in number of supplementary reports issued for errors in main reports

Conclusion: The current benefit demonstrated in our work is primarily due to the change in the data-entry processes, automated report generation, reduction in the errors and subsequent time spent in verification and correction of reports. Our work shows the benefit of segregation of data entry processes from report generation processes in addition to reduction of paper-trail due to introduction of an elaborate data-driven reporting platform, enhancing the quality of services provided by a clinical diagnostic laboratory.

OFP-15-003

AP Macroscopy mobile app for female genital macroscopy

F. Mundim*, F. Pereira, A. Mendonca, G. Salome, J. Oliveira, J. Araujo, M.C. Andrade, P. Mundim, A. Pereira

*UNIVAS/UNIFENAS, Brazil

Background & objectives: Due to the high demand, importance, and complexity of services in pathological anatomy, digital technologies have become fundamental for improving quality. According to the present, the objective was to develop an application for macroscopy of the female genital system.

Methods: The study applied in the technological production modality. Contextualized Instructional Design was chosen. The stages of development were: Analysis: literature review in PubMed / MEDLINE, SciELO and LILACS, Brazilian Society of Pathology and College of American Pathologists; Design: content production; Development: selection of tools; Implementation: configuration of tools and construction of download environment; Transition: performance of functionality tests.

Results: AP Macroscopy application presents 54 screens and 55 images, general information related to the macroscopy sector, and information about 11 types of macroscopic procedures of the female genital system. All of these 11 features: a brief introduction. Then, the procedures performed, on the piece/fabric (sections, handling, paintings), and macroscopic descriptions with options (Radio-Buttin) to issue text of the complete macroscopy. Subsequently, information about which sections to be represented will appear and make available two galleries: one with illustrations illustrating the anatomy of the organ and the sections to be performed and the other with photos of the organs and sections from the beginning to the end of the procedure.

Conclusion: The AP Macroscopy application was built and consisted of technological innovation in the macroscopic practice of pathological anatomy laboratories that aims to improve exams and optimize the service, open-collaborative online and shareable, contributing to an accurate microscopic diagnosis and ideal treatment for the patient.

OFP-15-004

Development of CNN-based algorithm for automatic recognition of the layers of the wall of the stomach and colon

I. Mikhailov*, A. Khvostikov, A. Krylov, P. Malkov, N. Danilova, N. Oleynikova

*Department of Pathology, Medical Research and Educational Center, Lomonosov Moscow State University, Russia

Background & objectives: Determination of foci of microinvasion of adenocarcinoma in polyps with low and high grade dysplasia is a rather difficult task, which can be tried to solve with the help of deep learning based methods.

Methods: We use two datasets that are developed for the purpose of whole-slide images (WSI) segmentation and tissue type recognition: NCT-CRC-HE-100K and PATH-DT-MSU. Our PATH-DT-MSU dataset contains 20 H&E WSI of digestive tract tumours with pixel-level annotation of 6 tissue types. We solve the segmentation problem via classification approach, with a simple AlexNet-based CNN trained for patch classification.

Results: The main goal for developing these algorithms is to automatically recognize the layers of the wall of the stomach and colon on WSI, namely the lamina propria, muscularis mucosa, submucosa, own muscle layer, subserous layer, serous membrane and adjacent areas adipose tissue. Since pixel-wise annotation of typical WSI is too time-consuming, we developed the patch classification model, applying which to overlapping patches results in getting coarse segmentation with reasonable accuracy. To adopt the model trained on NCT-CRC-HE-100K to PATH-DT-MSU we replace the last fully-connected layer and perform fine-tuning. The overall test accuracy of WSI classification is 0.93 on NCT-CRC-HE-100K and 0.8 on PATH-DT-MSU.

Conclusion: Thus, we managed to develop an algorithm that detects layers of gastric mucosa and depth of invasion of intestinal-type gastric tumours with acceptable accuracy. The use of developed post-processing methods of segmentation contour analysis allows to detect depth of invasion in some cases of diffuse-type tumours. Also the next step is to train deep learning algorithms to segment tubular and papillary structures, low and high grade dysplasia, foci of invasive adenocarcinoma.

Funding: This work was supported by RFBR grant 19-57-80014 (BRICS2019-394).

OFP-15-005

The impact of different mounting methods in the quality of whole slide images used for digital diagnosis in pathology

D. Ferreira*, J. Vale, M. Curado, A. Polónia, C. Eloy

*IPATIMUP, Italy

Background & objectives: The quality of digital images depends on the quality of glass slide preparations, namely of the mounting. This study compares glass coverslip, film coverslip, and liquid coverslip methods, to evaluate which is better for diagnosis in a digital pathology workflow.

Methods: Eighteen tissue samples of paraffin-fixed embed tissue processed paraffin blocks were prepared. From each block, three consecutive 3um sections were made and mounted using the three mounting methods. The slides were scanned in 3DHISTECH P1000 scanner, originally calibrated for film coverslip, and evaluated by two experienced pathologists on digital pathology.

Results: The film and liquid coverslip methods have similar results concerning the presence of air bubbles, air drying artifacts, tissue exposed and staining alterations. The glass coverslip method was the one with more air bubbles. The liquid coverslip showed more often alterations on the digital images, but like the other two methods, was found suitable for diagnosis. The liquid coverslip was the one that produced whole-slide images with the lower size.

Conclusion: The tested mounting methods generated glass slide preparations suitable to produce diagnostic quality digital images. The scanner calibration according to the mounting method may interfere with the quality of the digital image. Mounting methodology must be considered when adopting a digital workflow.

OFP-15-006

Implementation of a digital pathology workflow based on WaidX for rapid remote cytology diagnostics

M. Botteghi*, F. Trisolini, A. Paradiso, S. Martinotti, A. Procopio

*Università Politecnica delle Marche, Italy

Background & objectives: The ability to provide early diagnosis of female tumours has a strong impact on survival. Telemedicine is of great utility allowing for worldwide diffusion of good level healthcare practices. WorldConnex developed an integrated model for rapid accurate PAPtest remote diagnostics.

Methods: Women book the PAPtest on a web portal that assigns the collection center. The sample is taken and prepared using CYTOfast+ that produces high quality low-cost thin layer preparations. Slide are digitized, virtual slides are collected providing an AI-assissted pre-diagnostic support. A team of remote cytologists connected via WaidX carry out the diagnosis and send the digital report to patients.

Results: We are validating the platform under a wide range of conditions, including prohibitive settings of resource. The ongoing trial is highlighting the full satisfaction of the involved healthcare professionals. The integrated management chain of biological, digital and remote diagnostics components allows to manage a high quality diagnostic process with a time-to-response of 24 hours.

Conclusion: WaidX is a versatile telemedicine platform born from WorldConnex experience in Digital Health, devoted to provide answers to the huge need of telemedicine diffusion. Our project is characterized by a high level of innovation which increases efficiency and efficacy of healthcare practices and can boost the use of telepathology both in developed and developing countries. Innovative solutions are integrated into each element of the system to improve and optimize diagnostic processes.

OFP-15-007

Mapping the evidence for the WHO Classification of Tumours: a living evidence gap map by tumour type (WCT-EVI-MAP).

S. Armon*, F. Campbell, R. Cierco, I. Cree, I. Indave

*International Agency for Research on Cancer, WHO, France

Background & objectives: Decisions for the WHO-Classification-of-Tumours (WCT) as global reference tool should be informed by best available evidence, minimising risk of incorporating misinformation into clinical decision's pathway. We aim to map the evidence-base of the WCT, identifying gaps and pockets of low-level-evidence.

Methods: The WCT-EVI-MAP project will apply a mixed-method, stepwise approach to adapt Evidence-Gap-Map (EGM) methodology to the WCT. Steps include -development of a framework through expert consultation (e-Delphi study), -retrieving of evidence applying a living approach (continuous search for new evidence), -mapping of evidence in Mega-maps of group of tumour types using EPPIReviewer®, and descriptive analysis of WCT pre-post WCT-EVI-MAP.

Results: The resulting EGMs will describe the body of evidence for single tumour types, by research field and evidence-level in an easy-to-read visual representation. Mega-maps will be combined to provide an open-access online tool with living EGMs of the WCT. Dimensions of the map defined through the first phase of expert consensus will include evidence on epidemiology, molecular pathology, prognosis, as defined in the 5th edition of the WCT and three levels of evidence (low, medium and high) as defined by the current evidence pyramid. A strict multidisciplinary approach will be applied, and the results will be integrated into the strategic planning of the WCT 6th edition.

Conclusion: The WCT-EVI-MAP will represent a ground-breaking advance for the WCT and research in the field, positively impacting cancer diagnosis and management. The online tool will increase the discoverability and use of studies by the WCT decision-makers, research commissioners and stakeholders. Such long-term, positive impact has been already observed in other specialised fields with and constitutes an additional step towards evidence-based pathology.

OFP-15-008

SimInPath: mobile application to assess skills in pathology

E. Alcaraz-Mateos*

*Department of Pathology, Morales Meseguer University Hospital, Spain

Background & objectives: As an academic subject, Pathology is eminently theory based, and is routinely assessed in this fashion. The objective of this project was to design a non-profit application for mobile devices to assess competencies/practical skills in the field of Pathology.

Methods: There was an initial phase of development for the application and a second phase for testing.

A template for evaluation was created, including the descriptors for each stage for the following skills: macroscopic dissection, palpation of suitable lesions for fine needle aspiration (FNA), FNA, ultrasound-guided FNA, punch biopsy, and microscopic diagnosis. Each item could be evaluated using a Likert scale.

Results: A private company was hired to develop the SimInPath® (Simulation in Pathology) application, which took 6 weeks to complete. The Android system for mobile devices (both smartphones and tablets) was chosen as the platform for the application and it was made available for download through the GooglePlay platform. It was determined that the application would be free to download, avoiding advertising content.

In order to test the application, it was used to assess a group of students by an evaluator scoring the different tasks. The students' scores, in the form of checklists, were available for analysis after each assessment.

Conclusion: The SimInPath® application for mobile devices to assess practical skills in Anatomic Pathology was designed and launched.

This non-profit tool could be used to implement simulation-based medical education in medical schools or during residency, and, indeed, it could be used in the objective structured clinical examination (OSCE) assessment format.

In addition, it could provide greater visibility for the practical side of Pathology with an increase in student interest in the field.

OFP-16 | Molecular Pathology

OFP-16-001

Comparative pan-tumour analysis of a PD-L1 22C3 antibody laboratory-developed test protocol on the BenchMark XT and PD-L1 IHC 22C3 pharmDx

G. Vainer*, G. Zatara, L. Huang, S. Nuti, K. Emancipator

*Hadassah–Hebrew University Medical Center, Israel

Background & objectives: In the current analysis, we compared our PD-L1 22C3 antibody–based laboratory-developed test (LDT) on the Ventana BenchMark XT platform with PD-L1 IHC 22C3 pharmDx, an FDA-approved companion diagnostic for pembrolizumab across multiple tumour types.

Methods: Tumour specimens from multiple tumour types were stained with the 22C3 antibody, scored per the previously described LDT (Neuman T. J Thorac Oncol. 2016), and compared with PD-L1 IHC 22C3 pharmDx by a trained pathologist. PD-L1 was measured by combined positive score (CPS). Assay agreement was measured after determination of PD-L1 status per the LDT and PD-L1 IHC 22C3 pharmDx.

Results: Samples from 404 patients with cervical cancer (CC) (n=77), esophageal squamous cell carcinoma (n=80), head and neck squamous cell carcinoma (n=126), and urothelial carcinoma (n=121) were evaluated. Pan-tumour intraclass correlation coefficient (ICC) of PD-L1 as a continuous variable was 0.95 (95% CI, 0.94%-0.96%); Spearman correlation was 0.95. Among patients with CC, ICC was 0.92 (95% CI, 0.88%-0.95%); Spearman correlation was 0.93. The clinical interpretation of PD-L1 status (CPS ≥10) for CC samples using the LDT and PD-L1 IHC 22C3 pharmDx resulted in a negative percentage agreement of 91% (95% CI, 72%-97%), a positive percentage agreement of 100% (95% CI, 93%-100%), and an overall percentage agreement of 97% (95% CI, 91%-99%).

Conclusion: We demonstrated that our 22C3 antibody–based LDT on the Ventana BenchMark XT platform yielded high concordance with the FDA-approved PD-L1 IHC 22C3 pharmDx in a pan-tumour analysis and in patients with CC alone. These findings suggest the comparability of PD-L1 IHC 22C3 pharmDx with an LDT based on the 22C3 antibody across several tumour types. This analysis will be expanded to include additional indications for inclusion in the presentation pending data availability.

Funding: This study was sponsored by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA.

OFP-16-002

Exploratory biomarker analyses from a phase 2 trial evaluating sotorasib in patients with pre-treated KRASG12C-mutated non-small cell lung cancer (CodeBreaK 100)

M. Schuler*, A. Italiano, B. Li, G. Dy, F. Skoulidis, T. Kato, A. Anderson, A. Ang, G. Ngarmchamnanrith, A. Addeo, J. Wolf

*West German Cancer Center and German Cancer Consortium (DKTK), Germany

Background & objectives: In a phase 2 study (CodeBreaK 100/NCT03600883), sotorasib demonstrated a 37.1% objective response rate (ORR) and median progression-free survival of 6.8 months for pretreated patients with KRASG12C-mutated non-small cell lung cancer (NSCLC). We report efficacy by baseline biomarker subgroups.

Methods: Eligible patients (advanced KRASG12C-mutated NSCLC; prior therapies) received oral sotorasib (once-daily 960 mg). KRASG12C mutant allele frequency (MAF), tumour mutational burden (TMB), and gene mutations were analysed by next-generation sequencing. PD-L1 was assessed by PD-L1 IHC 22C3 pharmDx. Correlations between response and PD-L1, MAF, TMB or co-mutations were analysed. Association between MAF and response was analysed by logistic regression.

Results: ORR (95% CI) by subgroup was as follows. TP53 co-mutation status: mutant (n=84 evaluable patients) 39.3% (28.8–50.5); wild-type (n=20) 40.0% (19.1–63.9). STK11/KEAP1 co-occurring mutation status: mutant/mutant (n=13) 23.1% (5.0–53.8); mutant/wild-type (n=22) 50.0% (28.2–71.8); wild-type/mutant (n=7) 14.3% (0.4–57.9); wild-type/wild-type (n=62) 41.9% (29.5–55.2). TMB level: <10 mutations/Mb (n=69) 42.0% (30.2–54.5); ≥10 mutations/Mb (n=15) 40.0% (16.3–67.7). PD-L1 level: tumour proportion score (TPS) <1% (n=44) 47.7% (32.5–63.3); TPS 1–49% (n=33) 39.4% (22.9–57.9); TPS ≥50% (n=9) 22.2% (2.8–60.0). Response was independent of KRASG12C MAF: odds ratio for each 0.10 increase in MAF was 1.11 (95% CI 0.88–1.39). OS remained immature.

Conclusion: In these exploratory analyses of the registrational phase 2 CodeBreaK 100 trial, the clinical benefit of sotorasib in KRASG12C-mutated NSCLC was observed across a range of patient subgroups including patients with low PD-L1 expression level and those with co-occurring STK11 mutation. A signal of interaction between response rate and KEAP-1 mutations merits further study in larger populations.

Funding: Amgen Inc.

OFP-16-003

Clinicopathological features of four cases of BCOR-CCNB3-positive sarcomas

B. Rekhi*, V. Vengurlekar, O. Shetty

*Tata Memorial Hospital, India

Background & objectives: Sarcomas with BCOR genetic alterations are included in the recent WHO classification of soft tissue and bone tumours. Currently, there is a single reported study from our country on BCOR-CCNB3-positive sarcomas. We present clinicopathological features of 4 additional such cases.

Methods: Nine cases of undifferentiated round to spindle sarcomas were tested for BCOR-CCNB3 fusion by reverse transcriptase-polymerase chain reaction. All these tumours were negative for EWSR1 gene rearrangement and a single case, also for SS18 rearrangement, by fluorescence in-situ hybridization.

Results: Four tumours occurred in 3 males(13-year-old, 7-year-old, and 16-year-old) and a single female(37-year-old), in tibia, femur, temporal region, and thigh, respectively. Histopathologically, tumours were composed of round(n=4), polygonal(n=2), to spindly cells(n=2) in a myxoid matrix(n=3) with interspersed thin-walled vessels(n=4) and focal necrosis(n=2). Immunohistochemically, tumour cells displayed dot-like reactivity for MIC2/CD99 (4/4), positivity for SATB2 (3/4), BCOR (2/2), focal positivity for EMA (1/3), and negativity for desmin (0/4) and WT1(0/3). Therapeutically, 2 patients underwent neoadjuvant chemotherapy (99% response and 78% response), followed by surgical resection. Two patients were offered palliative radiotherapy, in view of metastasis at presentation and unresectability. Three patients developed lung metastasis and a single patient developed local recurrence.

Conclusion: Certain morphological features, such as spindle and polygonal cells, in addition to round cells, along with myxoid stroma, intervening vessels; dot-like immunoreactivity for MIC2, lack of EWSR1 rearrangement, and intraosseous location constitute as diagnostic clues for BCOR-CCNB3-positive sarcomas. SATB2 and BCOR are useful immunostains for triaging such cases for BCOR-CCNB3-fusion testing.

OFP-16-004

Development of an optimised diagnostic algorithm using multiplex immunochemistry (IHC) for excluding diagnosis of carcinoma-of-unknown-primary-origin, based on experience from the Phase II CUPISCO trial

C. Pauli*, X. Matias-Guiu, M. Chenard, P. Banks, N. Chalabi, G. Erb, P. Toro, H. Moch

*University and University Hospital Zurich, Switzerland

Background & objectives: High screening failure rates observed in CUPISCO (PMID: 33687747; NCT03498521) highlight the need to improve carcinoma-of-unknown-primary-origin (CUP) diagnosis (improved accuracy; shorter time to diagnosis; reduced tissue consumption). Therefore, we intended to optimise pathology work-ups via use of brightfield multiplexed IHC.

Methods: A panel of experts evaluated over 800 pathology work-ups from CUPISCO according to ESMO guidelines, in order to improve the efficiency of establishing an appropriate diagnosis of non-CUP versus real CUP cases. On this basis we developed a systematic diagnostic algorithm utilising automated brightfield multiplexed chromogen-based IHC assays to screen a broad spectrum of markers.

Results: We defined an algorithmic system featuring up to five sequential multiplex IHC-testing panels, each analysing five markers, that would be suitable for routine clinical use. A general panel including cytokeratin 7, cytokeratin 20, vimentin, synaptophysin and thyroid transcription factor 1 enables an initial broad screening approach, subsequent to haematoxylin–eosin stain interpretation and assessments of the patient’s clinical characteristics. Then, more specific panels featuring markers for gastrointestinal/pancreatic, lung/kidney or breast/gynaecological cancers can be selected for further, more focused analyses. The results of our feasibility testing, as well as the potential implications for patient management and improving CUP diagnosis, will be presented.

Conclusion: The proposed methodology may improve the detection of primary cancers in complex cases: avoiding the incorrect diagnosis of CUP. The exclusionary diagnosis of CUP can be optimised and accelerated by the use of an algorithmic progression via the application of sequential multiplex IHC panels. Such a system reduces the amount of tumour tissue needed for preliminary assessment and preserves material for further genomic testing. This will help to optimise the patient care strategy; allowing access to molecular-guided therapies.

Funding: F. Hoffmann-La Roche Ltd.

OFP-16-005

The emerging relevance of RNA modifications in tumour biology: VIRMA contributes to testicular germ cell tumours aggressive phenotype and chemotherapy resistance

J. Lobo*, V. Miranda-Gonçalves, C. Guimarães-Teixeira, D. Barros-Silva, R. Guimarães, M. Cantante, I. Braga, C. Oing, D. Nettersheim, L. Looijenga, R. Henrique, C. Jeronimo

*IPO Porto - Department of Pathology & Cancer Biology and Epigenetics Group, Portugal

Background & objectives: Testicular germ cell tumours(TGCTs) are developmental cancers, reflecting embryogenesis. The recent field of RNA modifications is being increasingly implicated in such events. We previously demonstrated the relevance of VIRMA in TGCT patient samples, and now investigate this in vitro/in vivo.

Methods: We study the role of N6-methyladenosine (m6A) and related writers, readers and erasers in 4 cell lines representative of TGCTs, including after treatment with ATRA and in isogenic clones made resistant to cisplatin. Also, we investigate the immunoexpression of METTL3 in a TGCT tissue cohort.

Results: We show differential expression of m6A players in cell lines representative of seminoma/non-seminoma. We demonstrate shifts in expression during differentiation with ATRA treatment and also among cells sensitive and resistant to cisplatin treatment, implicating m6A modification in the acquisition of therapy resistance. METTL3 immunoexpression was significantly higher in non-seminomas (p<0.0001), but did not significantly impact relapse-free survival. CRISPR/Cas9-mediated knockdown of VIRMA, a component of the writer complex, resulted in disruption of the complex, decreased m6A deposition, reduced tumour aggressiveness (decreasing viability and proliferation) and potentiated response to cisplatin treatment (eliciting higher DNA damage). We are currently further validating these findings in vivo, using the chick chorioallantoic membrane assay model.

Conclusion: RNA modifications are a current hot topic in research, being implicated in tumour genesis, biology and resistance to therapy, with VIRMA being the major representative player in TGCTs. This is interesting given the recent development of targeted drug compounds directed at elements of the m6A methyltransferase complex, which can be envisioned as clinically useful in this particular tumour model.

Funding: FCT (SFRH/BD/132751/2017 and PTDC/MEC-URO/29043/2017). MSD (“Prémio de Investigação em Saúde”), Banco Carregosa/SRNOM and Fundação Rui Osório de Castro/Millennium bcp.

OFP-16-006

Genomic testing approaches used to identify neurotrophic tyrosine receptor kinase (NTRK) gene fusions for patient enrollment in clinical trials of larotrectinib

J. Hechtman*, S. Roy-Chowdhuri, M. Rudolph, C.M. Lockwood, J. Silvertown, J. Wierzbinska, R. Norenberg, H. Nogai, T.W. Laetsch, D.S. Hong, A. Drilon, E.R. Rudzinski

*Neogenomics Laboratories, USA

Background & objectives: NTRK fusions are oncogenic drivers and are predominantly detected by NGS, PCR, or FISH. Larotrectinib, a first-in-class, highly selective, CNS-active TRK inhibitor, demonstrated a 78% objective response rate and a 36.8-month median PFS across multiple solid cancers (July 2019 data-cut).

Methods: Details of the testing methods used to diagnose patients with TRK fusion cancer enrolled in three larotrectinib clinical trials (NCT02122913, NCT02576431, NCT02637687) are reported. NTRK status was determined by local molecular testing. ETV6-NTRK3 fusions were considered inferred based on FISH break-apart results for tumour types in which NTRK fusions are pathognomonic. Data cut-off: 20 July 2020.

Results: The analysis included 225 patients (129 adults [57%]) with 19 different tumour types. Most common gene fusions were ETV6-NTRK3 (41%), TPM3-NTRK1 (16%) and LMNA-NTRK1 (8%); 54 different fusion partners were identified, 39 (72%) of which were unique occurrences. Testing methodologies/incidence of fusion partners varied by tumour type. Most common method was NGS (196/225, 87%: DNA in 53/196 [27%], RNA in 96/196 [49%], DNA/RNA in 46/196 [23%], unknown in 1 [1%]) followed by FISH (14/225, 6%) and PCR (12/225, 5%). NanoString, Sanger sequencing and chromosome microarray were each utilized once. ETV6 and/or NTRK3 FISH were employed for specific tumour types (eg. secretory breast, IFS, salivary gland), detecting 14% of ETV6-NTRK3 fusions.

Conclusion: NTRK gene fusions occur with many partners with the majority occurring at a low frequency across multiple tumour types, supporting the need for validated and appropriate testing methodologies that work agnostic of 5’ partners.

Funding: Bayer Pharmaceuticals, Inc, and Loxo Oncology, a subsidiary of Lilly

OFP-16-007

The EGFR, ALK and ROS1 mutation profile of non-small cell lung carcinomas in the Turkish population: a single-centre analysis

E. Gun*, I.E. Cakir

*Izmir Katip Celebi University, Turkey

Background & objectives: The management of non-small cell lungcarcinomas(NSCLC) has changed with the identification of the molecular pathways which are now used in targeted-therapies. We aimed to reveal the 2-year epidermal growth factor(EGFR),anaplastic lymphoma kinase(ALK) and ROS proto-oncogene1(ROS1) mutation profile in the Turkish population.

Methods: The histopathological and molecular data of all NSCLC cases that were evaluated in our department between May 2019 and April 2021 were retrieved from the archives. The demographic data of the patients, type (cell block, biopsy, resection) and the localization (primary/metastatic) of the specimen in which the molecular testing was done, the histopathological diagnosis, and the mutation rates were noted.

Results: A total of 129 NSCLC (95 adenocarcinomas, 20 squamous cell carcinomas [SCC], 14 NSCLC,NOS), cases underwent molecular testing(M/F:121/28, aged 40-87). The molecular testing was performed on cell blocks obtained from cytological specimens in 46, biopsies in 69, and resections in 14 cases. EGFR mutation was seen in 15 (11,6%) cases (three exon 18[allcodon 719],five exon 19,two exon 20 [1 T790M, 1 codon 768] and five exon 21[4 L858R, 1 L861Q]). The mean age of EGFR-mutant patients was 60 (45-76) with 25% of all females(n=7) and 6.6% of all males(n=8). ALK mutation was detected in 5 (3,8%) patients (M/F:2/3,mean 65,6years) whereas ROS1 mutation was detected in 2 (1,5%) (1 male, 1 female).

Conclusion: It is well-established in the literature that EGFR-activating mutation rates vary depending on the country/race. We concluded that the EGFR-activating mutation rates of the Turkish population are similar to the European molecular data instead of the Asian. The majority of the cases with EGFR, ALK and ROS1 mutations were adenocarcinomas in our series, however exon 20 - T790M mutation in one case with SCC was seen. ALK and ROS1 mutation rates also seem consistent with the literature.

OFP-16-008

Putative germline variants from tumour-only genel panel sequencing: results of a single-centre study

S. Dintner*, M. Schlesner, M. Harloff, T. Schaller, M. Frühwald, M. Trepel, B. Märkl, M. Kuhlen, R. Claus

*University Medical Center Augsburg, Germany

Background & objectives: Multi-gene panel NGS from tumour tissues has become the mainstay personalized oncology. However, when suggestive VAF around 50% or higher are found it remains unclear whether variants in cancer genes identified by tumour-only sequencing might potentially be of germline origin.

Methods: A total of 2057 gene panel tumour-only NGS analyses from adult and paediatric patients with solid tumours who were diagnosed between 2018 and 2020 were reviewed. NGS of 83 cancer related genes was performed. Results were reviewed for potential PGVs using following criteria: Pathogenic variants with an allele frequency ≥ 40% and a VAF to tumour purity ratio ≥ 50%.

Results: Putative PGVs with a VAF ≥ 40% and a VAF/tumour purity ratio ≥ 50% were detected in 408 patients. The list of filtered putative PGVs included those in cancers of high rates of susceptibility and with a high proportion of patients with known inherited PGVs (breast, colorectal, ovary). Further filtering by exclusion of genes with high prevalence and strong association with syndromic phenotypes resulted in 250 PGVs in 46 genes. The identified variants included those associated with genes with high germline conversion rate (BRCA, PALB2) and to a lower degree those with lower reported germline prevalence (EGFR, IDH1). In selected cases, the suspicious PGVs were successfully verified by germline analysis.

Conclusion: Although tumour-only sequencing provides a cost-effective approach to identifying somatic variants present in the tumour, it will also detect any germline variants present. These findings may influence patient care by impacting on systemic therapy choices, surgical decisions, additional cancer screening, and genetic counseling in families. The findings of this study suggest that the application of systematic filter steps combined with automated flagging and concise manual review as proposed by current guidelines can provide an opportunity to detect PGVs.

OFP-16-009

Laboratory variation of molecular testing in a Dutch cohort of metastatic non-small cell lung cancer patients from 2017

B. Cajiao Garcia*, C.C. Kuijpers, M.M. van den Heuvel, A.S. van Lindert, R.A. Damhuis, S. Willems

*Department of Pathology, University Medical Centre Groningen, The Netherlands

Background & objectives: Adequate and timely testing for genetic alterations in non-small cell lung cancer (NSCLC) is necessary to consider targeted therapy. Currently, within a 2017 cohort we assessed whether molecular testing improved after 2015.

Methods: All stage IV non-squamous NSCLC with incidence year 2017 from the Netherlands Cancer Registry were matched to the Dutch pathology registry (PALGA). Using information extracted from pathology excerpts, proportions of tumours tested for EGFR/KRAS, BRAF, and HER2 mutation, ALK, ROS1, and RET rearrangement <3 months after diagnosis were determined and variation between 42 laboratories was assessed.

Results: Of 3746 identified patients, we have currently analysed 3647 (97%). Ninety-two patients were non-eligible after matching, leaving 3555 (94%) patients. EGFR/KRAS testing was performed in 2992 patients (84%) (laboratory variation 68-100%). Of the EGFR/KRAS wildtype tumours (n=1516), 1392 (92%) were tested for BRAF (14-100%), 1309 (86%) for HER2 (18-100%), 1231 (81%) for ALK (50-100%), 952 (63%) for ROS1(3-100%), and 663 (44%) for RET (0-100%). The reason for not testing was not reported for the majority of patients. Insufficient tumour tissue and inappropriate specimen were the most stated reasons for not testing within the reported group.

Conclusion: These data show significantly higher EGFR/KRAS, ALK and ROS1 testing proportions compared to 2015. Further improvement remains possible, in some laboratories more than in others, and especially for ROS-1 and RET testing, to identify candidates for targeted therapy. Initiatives for improvement will involve starting a dialogue with professionals on a regional level, where these findings and recommendations of a best practice session will be discussed.

Funding: Roche, Pfizer, AstraZeneca

OFP-16-010

Prevalence of KRAS p.(G12C) in stage IV non-squamous NSCLC patients in the Netherlands; a retrospective cohort study

B. Cajiao Garcia*, C.C. Kuijpers, A.J. van der Wekken, L. van Kempen, E. Schuuring, S. Willems

*Department of Pathology, University Medical Centre Groningen, The Netherlands

Background & objectives: KRAS is the most frequent mutation in cancer, especially KRAS p.(G12C) (39%-42% KRAS-mutant NSCLC). Recently, clinical trials with drugs specifically targeting KRAS p.(G12C) showed promising responses. We aim to investigate the prevalence of KRAS p.(G12C) mutations within a NSCLC cohort.

Methods: Patients diagnosed with stage IV non-squamous NSCLC in 2013, 2015, and 2017 in the Netherlands were retrieved from the Netherlands Cancer Registry (NCR) and the Dutch Pathology Registry (PALGA). After matching of the databases pertinent clinical and pathological variables were extracted. Testing rates and prevalence of KRAS p.(G12C) were calculated from the collected data.

Results: A total of 10,851 tumours were selected from the NCR and matched with PALGA. After exclusion of 596 non-eligible patients due to exclusion criteria, 10,255 patients were included, of whom 7,908 (77%) were tested for KRAS mutations within 3 months after diagnosis. Testing rate increased from 71.8% in 2013, to 80.9% and 83.3% in 2015 and 2017, respectively. An increase in the ≥65-year-old population (50.2% (2013) to 57.5% (2017), p<0.01) and an increase in histological/cytological specimen ratio (65.6% (2015) to 71.4% (2017), p<0.01) was observed. In the total population the prevalence for KRAS p.(G12C) was 15.5%.

Conclusion: Using data systematically collected in Dutch national cancer and pathology registries, the prevalence of KRAS p.(G12C) mutations in the entire population of patients with stage IV-NSCLC in the Netherlands is 15.5%. Although the testing rate increased from 2013 to 2017, there seems to be room for improvement although reasons why a test was not requested was not systematically captured.

Funding: Amgen

OFP-16-011

Molecular profiling of BRCA1/2 genes by NGS in tumoral samples from ovarian cancer patients

A. Vivancos, M. Biscuola, G. Navarro, M.A. López, J. Matito, L. Camacho, A. Blanco, M. Gomez, E. Moragon, E. de Alava, B. Bellosillo*

*Hospital del Mar, Barcelona, Spain

Background & objectives: Analysis of BRCA1/2 genes in ovarian cancer patients was historically assessed in the germ line and is now moving to tumoral tissue. Our aim was to evaluate the sensitivity of mutation detection by NGS approaches in FFPE tumoral samples.

Methods: Specimens from 81 previously characterized germline ovarian cancer patients from three centers were included. Each center studied their cases with the available NGS technique: customized hybrid capture based panel (VHIO), BRCAplus amplicon panel, Qiagen (Hospital del Mar) and Oncomine BRCA Research Assay, ThermoFisher (Virgen del Rocio). Sequencing was performed on Illumina (capture panel and Qiagen panel) or GeneStudio S5 systems.

Results: Of the 81 samples initially selected, 10 samples were not evaluable due to insufficient quality of the DNA obtained from the sample. Of the remaining 71 samples (30 cases with BRCA1 germline mutations, 17 cases with BRCA2 germline mutations, and 24 cases without BRCA1 / 2 germline mutations), the previously identified germline mutations were detected in 47/47 cases (100%). In addition, somatic mutations were identified in 9 cases with no germline mutations, 5 in BRCA1 and 4 in BRCA2 with allelic frequencies between 20-47%. In addition, in 2 cases that presented germline mutations, a somatic mutation was also detected (1 in BRCA1 and 1 in BRCA2)

Conclusion: These results indicate that the analysis in tumoral tissue has adequate sensitivity for the detection of germline mutations in the BRCA1/2 genes if the quality of the tissue DNA is sufficient. Furthermore, the tumoral biopsy study allows us to identify somatic alterations in these genes.

OFP-16-012

Multiparametric (2+3) assessment of PD-L1 expression in tumour tissue: a novel, rapid and easy-to-use algorithm to capture more of the biological complexity and minimise inter- and intra-observer variability

A. Baltan*, S. Costache, H. Haynes, K. Billingham, T. Thomas, A. Chefani, V. Herlea, S. Wedden, C. D'Arrigo

*University Emergency Hospital, Bucharest, Romania

Background & objectives: PD-L1 counting of positive TC and/or IC is difficult and time-consuming near the positivity thresholds, correlation between small biopsy and excision can be poor and morphological data are not captured. We describe a novel algorithm to address these issues.

Methods: We assessed %TC, %IC, extent, clustering and distribution (2 +3) by eyeballing using 7 bins for each parameter. Matched diagnostic and excision biopsies were stained with on-label SP263 CDx and digitised (3DHistech). An initial set of 20 cases were scored by all pathologists. Non-concordant cases were reviewed and given a score by consensus. Each pathologist then assessed 25 additional cases.

Results: Six consultant pathologists, two trainee pathologists and one clinical scientist participated in the study. Training consisted of self-learning using a short presentation; this suggests that the 2+3 system [SW1]would be easy to introduce in the diagnostic routine. The 2+3 scoring algorithm was used on TNBC and NSCLC and showed excellent inter- and intra-observer concordance when compared to established CPS, TPS and IC/TC algorithms[SW2]. It also improved correlation between small biopsies and excision of the same tumour when compared to established PD-L1 algorithms used in oncology.

Conclusion: The 2+3 algorithm is easy to use, reproducible, captures more of the biological diversity and is less sensitive to tissue sampling. It reduces the influence on the overall score of imprecisions in single parameters. The 7 bins scale facilitates observer concordance. Morphological parameters such as IC distribution, important in identifying responders to immune checkpoint therapy, are part of the assessment and may improve prediction. Clinical trials will provide the correct weight to each parameter for best patient selection.

OFP-17 | Nephropathology

OFP-17-001

Diagnosis of membranous nephropathy and differentiation between primary and secondary forms applying immunohistochemistry using C4d and PLA2r antibodies

M. Zivotic*, M. Tubic, D. Petrovic, J. Filipovic, S. Radojevic Skodric, R. Naumovic, A. Kezic, D. Paripovic, D. Dundjerovic

*Institute of Pathology, Faculty of Medicine, University of Belgrade, Serbia

Background & objectives: Appreciating a huge effort to clearly separate primary from secondary membranous nephropathy (MN), due to direct influence on patients' treatments, several biomarkers have been suggested, including C4d and PLA2r.

Methods: Insufficient studies concerning the aforementioned pathohistological approach have led us to explore the sensitivity and specificity of recently proposed biomarkers in distinguishing primary and secondary MN. We applied immunohistochemistry (C4d, 1:50, ab167093, Abcam; PLA2r, 1:1000, ab188028, Abcam) using 21 kidney biopsies (13 primaries, 8 secondary), as well as 40 renal samples of various non-MN diagnosis.

Results: C4d and PLA2r were expressed in glomeruli in all MNs (21/21), both primary and secondary. Furthermore, C4d was not observed among non-MN cases, while PLA2r was detected in the majority of them (39/40 non-MN diagnoses: focal segmental glomerulosclerosis (n=5), minimal change disease (n=3), mesangioproliferative glomerulonephritis (n=14), IgA nephropathy (n=4), post-infective glomerulonephritis (n=4), hypertensive nephropathy (n=1), diabetic nephropathy (n=2), rapidly progressive glomerulonephritis (n=3), lupus nephritis (n=3)). These results indicate the absolute specificity and sensitivity (100%) of C4d antibody in diagnosis of MN regardless of the etiology. However, despite an absolute sensitivity, PLA2r failed to differentiate primary from secondary MN due to extremely low specificity (2.5%).

Conclusion: Confirmation of membranous nephropathy could be done by C4d in each case, without false results, either positive or negative. However, differentiation of primary from secondary MN is not reliable using the proposed PLA2r method, thus seeking a better biomarker is warranted.

Funding: Ministry of Education, Science and Technological Development of the Republic of Serbia (project No. OI 175047)

OFP-17-002

Morphology of childhood and adult-onset lupus nephritis

M. Zivotic*, S. Radojevic Skodric, J. Filipovic, D. Petrovic, A. Mioljevic, R. Naumovic, A. Kezic, D. Paripovic, N. Stajic, D. Dundjerovic

*Institute of Pathology, Faculty of Medicine, University of Belgrade, Serbia

Background & objectives: Systemic lupus erythematosus (SLE) could affect the integrity and function of many organs, including the kidneys. Although the frequency of SLE is less common in children than in adults, affected children develop lupus nephritis (LN) significantly more often.

Methods: In order to analyse relevant clinical (gender, frequency of LN as the first manifestation of SLE, proteinuria and serum creatinine values) and pathohistological parameters (LN classes, activity and chronicity index), this study included 217 biopsy samples of kidney tissue. Patients were divided into two groups: patients under (n=35) and over (n=183) 18 years.

Results: Among investigated clinical data, serum creatinine values were significantly lower in the paediatric population (71.6±16.4 μmol/l) than in adults (115.5±64 μmol/l), p<0.001. Parameters which define disease activity index were similar in both groups with exception of interstitial infiltration that was significantly higher in the adult group, p=0,003. Chronicity index (p=0,002) as well as the tubulointerstitial parameters that determine it (tubular atrophy (p<0,001) and interstitial fibrosis (p=0,011)) were also higher in adults. Blood vessel involvement was frequently detected in adult biopsies (p<0,001).

Conclusion: Serum creatinine values are significantly higher in the adult population of LN. Pathohistological findings indicate that glomerular LN lesions do not differ significantly in regard to activity and chronicity index in paediatric and adult populations, but degrees of tubulointerstitial lesions, either active or chronic, are significantly higher in adult-onset LN.

Funding: Ministry of Education, Science and Technological Development of the Republic of Serbia (project No. OI 175047)

OFP-17-003

NanoString transcriptome analysis with the B-HOT panel for clinical diagnostics on for-cause kidney transplant biopsies

H. Varol*, A. Ernst, I. Cristoferi, W. Arns, C. Baan, D. Hesselink, F. van Kemenade, D. Mustafa, M. Snijders, D. Stippel, J. Becker, M. Clahsen-van Groningen

*Department of Pathology, University Medical Center Rotterdam, The Netherlands

Background & objectives: Transcriptome analysis could help in diagnosing rejection and is an Additional Diagnostic Parameter for AMR. NanoString is a novel and promising technique. We evaluated the commercially available Banff-Human Organ Transplant Panel (B-HOT panel) using NanoString on for-cause kidney transplant biopsies.

Methods: Transcriptome analysis using the B-HOT panel (770 transcripts) of NanoString was performed on 96 formalin-fixed paraffin-embedded for-cause kidney transplant biopsies retrieved from the archives of the Erasmus MC Rotterdam and the University Hospital of Cologne. Three groups were compared: antibody-mediated rejection (AMR, n=32), T cell-mediated rejections (TCMR, n=32), and non-rejection (controls, n=32). Data was analysed using the nSolver analysing software.

Results: 22 mRNA transcripts (CXCL1, FCGR3A, GNLY, ROBO4, CCL3, CXCL10, TNF, CD74, PLAT, ICAM2, PSMB10, LST1, CRIP2, EMP3, CX3CR1, HSPA12B, SH2D1B, LHX6, CD160, S1PR5, TBX21, TRDC) were found to be differentially regulated (upregulated) between AMR and controls after false discovery rate (FDR) corrections. Eight (PSMB10, CX3CR1, TNF, CXCL11, GNLY, CCL3, CD160, CXCL10) of these 22 transcripts were also found to be upregulated in TCMR vs controls. No transcript was found to be differentially regulated between AMR and TCMR after FDR correction. Notably, even promising transcripts (TNFSF8, C9, TOX2, CD70) showed overlap in expression between AMR and TCMR.

Conclusion: The B-HOT panel can help to distinguish kidney transplant biopsies with rejection from biopsies without evidence of rejection. Caution should be taken regarding the clinical value of this platform regarding the more challenging and clinically important distinction between diagnosis of AMR (most cases of which show an additional component of Borderline or TCMR) and pure TCMR or Borderline. The B-HOT panel could help us identify the most promising transcripts for this differential diagnosis on larger cohorts.

OFP-17-004

An audit of Electron Microscopic (EM) evaluation of native renal biopsies

S. Singh*, C. Roufosse, A. Smith, H. Cook, L. Moran

*Imperial College Healthcare NHS Trust, London, United Kingdom

Background & objectives: Aim: To carry out a retrospective survey of native renal biopsies to determine the percentage of cases in which a) EM evaluation was necessary to make the correct diagnosis; and b) EM evaluation provided clinically relevant additional information.

Methods: Methods: We retrospectively reviewed 100 consecutive native renal biopsies. We excluded cases in which no sample was available for EM or the EM sample was inadequate. We classified the EM as necessary for diagnosis; adding information to diagnosis; and not necessary/not adding information.

Results: In 81 cases, the main diagnosis was glomerular; tubulointerstitial in 10; and in 9 it was mixed. In 20% of cases, correct diagnosis and classification would not have been possible without EM evaluation. 19/ 20 were glomerular diseases, and 1/20 was a tubulointerstitial disease. In an additional 44% cases, EM evaluation provided clinically relevant information. Amongst cases where the main diagnosis was glomerular, EM was necessary in 23% cases and helpful in other 47% and where it was tubulointerstitial EM was necessary in 10% and added information in 30%. The most common situations where EM was neither necessary nor helpful were ANCA- or anti-GBM- glomerulonephritis (n=5/5) and IgA nephropathies (n=14/23)

Conclusion: EM is reported as essential for diagnosis in around 20% of biopsies, and to add value in about 50%, although recent data is not available. Our Trust carries out EM evaluation on all native renal biopsies, giving us the impetus to audit the contribution of EM in native renal biopsy reporting. Our audit confirms the accuracy of published figures for when EM is necessary or useful and supports continued practice of taking a sample for EM in all native biopsies.

OFP-17-005

Heterozygous COL4A3 and COL4A4 patients with classic Alport syndrome morphology – unexpected genetic testing results after kidney biopsy

P. Šenjug*, M. Horaček, T. Nikuševa Martić, M. Glavina Durdov, G. Đorđević, M. Ćorić, D. Galešić Ljubanović

*Department of Nephropathology and Electron Microscopy, Dubrava University Hospital, Zagreb, Croatia

Background & objectives: Heterozygous Alport spectrum patients with COL4A3 or COL4A4 mutations usually present as thin glomerular basement membrane nephropathy on kidney biopsy. Here we present cases of heterozygous patients with COL4A3 or COL4A4 mutations with classic Alport syndrome morphology.

Methods: Fifteen patients, six males and nine females (age 2-47 years) with pathohistological diagnosis of Alport syndrome (AS) were tested by NGS sequencing (Illumina MiSeq platform) for COL4A3, COL4A4 and COL4A5 mutations as a part of Croatian Science Foundation project “Genotype-Phenotype correlation in Alport’s syndrome and Thin Glomerular Basement Membrane Nephropathy”.

Results: At the time of kidney biopsy all patients presented with haematuria and 8 of them with proteinuria. Only one patient had severe decline in eGFR while all other patients had normal eGFR. There were 12 different mutations present (7 in COL4A3 and 5 in COL4A4), 6 of them being novel, previously undescribed. In light microscopy 3 patients showed focal segmental glomerulosclerosis. In three patients there were interstitial foamy cells and only the oldest patient had significant interstitial scaring (50%). All patients had classic Alport syndrome morphology on electron microscopy. Immunohistochemical staining for COL4A3 and COL4A5 was performed in four patients and showed normal distribution.

Conclusion: Diagnostic process of Alport spectrum disorders can be challenging. Phenotype variability is very often among patients. Although kidney biopsy gives insight in to the degree of kidney parenchyma damage genetic testing is necessary for complete diagnosis and patient workup.

Funding: Croatian Science Foundation, project Genotype-Phenotype Correlation in Alport’s Syndrome and Thin Glomerular Basement Membrane Nephropathy (IP-2014-09-2151)

OFP-17-006

Automated renal structure recognition: Multi-class segmentation of differently stained kidney tissues using convolutional neuronal networks (CNNs)

J. Schmitz*, D. Christensen, L. Müller, L. Neugebohren, T. Zachrau, N. Vasileiadis, T. Johannes, A. Plesch, T. Lörch, W. Gwinner, J.H. Bräsen

*Nephropathology Unit, Institute of Pathology, Hannover Medical School (MHH), Germany

Background & objectives: Pathological diagnostics in kidneys are still based on semi-quantitative eye-balling methods. In former studies, we showed predictive value of precise immune cell quantification in allografts using digital semi-automated techniques. We now aim to achieve fully automated segmentation workflow with CNNs.

Methods: Standard routine stains (immuno/histochemistry, immunofluorecence) were digitized (20x) with Metafer, a commercial scanning/imaging platform. Diagnostically relevant anatomical compartments (cortex, medulla, glomeruli, tubuli (proximal/distal/collecting duct), glomerular/peritubular capillaries, nuclei) were manually annotated to generate data sets on human renal biopsies and nephrectomies. Data were used to train multi-class semantic segmentation CNNs with broad data augmentation to achieve a robustness against staining variances.

Results: On Jones-HE stains, a cortex-medulla-extrarenal CNN reveals pixel based hit rates above 98%, detection of glomeruli show a hit rate above 98%, a multi-class CNN for tubules, tubular membranes and peritubular capillaries results in a hit rate close to 93% and pixelwise nuclear-based cell detection shows hit rates above 98%. Identification of cell location in interstitium, tubuli, glomeruli, peritubular and glomerular capillaries reached very high hit rates: Glomerular endothelial cells actually result in 83% true positives, 13% false negatives and 4 % false positives. Ongoing work also includes detection of arteries and development of classifiers for atrophic tubuli and immune-cell typing within respective structures.

Conclusion: Structure segmentation based on CNNs can complement and specify classical nephropathological diagnostics, especially for spatial risk marker evaluation in early transplant biopsies.

Funding: German Federal Ministry of Education and Research (BMBF; funding no. 13GW0399 A-B)

OFP-17-007

Determination of antibodies that can be used in the differentiation of primary and secondary membranous nephropathy and investigation of the relationship of these antibodies with secondary causes

E. Köse*, Y. Yuyucu Karabulut, K. Turgutalp

*Mersin University Medical Faculty, Medical Pathology Department, Turkey

Background & objectives: Membranous nephropathy (MN) is the most common primary glomerular disease in adults that causes nephrotic syndrome. We aim to evaluate Phospholipase-A2 receptor (PLA2R), Thrombospondin type-1 domain-containing 7A (THSD7A), and Neural epidermal growth factor-like 1 protein (NELL1) in MN patients.

Methods: 122 cases of MN and 21 cases of Class V Lupus nephritis diagnosed at Mersin University Medical Faculty Medical Pathology Department between 2008 and 2020 are included in this study. Immunohistochemical staining for PLA2R, THSD7A, and NELL1 was performed on the tissue sections obtained from paraffin-embedded blocks of renal biopsy materials.

Results: Percentage of cases positive for PLA2R, THSD7A, and NELL1 were found to be 64.9%, 6.7%, and 6.5% respectively. NELL1 positivity was associated with female gender and Diabetes Mellitus. THSD7A positivity was associated with the absence of hypertension clinically and; intraluminal/mesangial polymorphonuclear lymphocytes, interstitial inflammation, evidence of tubular damage, tubulitis, and calcifications histologically. It was also associated with fibrinogen positivity in an immunofluorescence study. PLA2R positivity was associated with lower serum IgA antibody levels.

Conclusion: The traditional classification of membranous nephropathy does not take associated antigen types and their unique clinical, histopathological and immunological profiles into account. Associated antigens of membranous nephropathy patients can be determined in most of the membranous nephropathy patients and therefore should be the basis of histopathological evaluation and clinical management.

OFP-17-010

A decentralised kidney transplant biopsy classifier incorporating different molecular platforms

I. Cristoferi*, M. Van Baardwijk, J. Ju, H. Varol, M.E. Reinders, R.C. Minnee, A. Stubbs, M. Clahsen-van Groningen

*Erasmus MC Transplant Institute, University Medical Center Rotterdam, Department of Pathology, Clinical Bioinformatics Unit, Erasmus MC, University Medical Center Rotterdam, Department of Surgery, Division of HPB & Transplant Surgery, University Medical Center Rotterdam, The Netherlands

Background & objectives: An optimal decentralized molecular kidney transplant biopsy classifier allows the input of different gene expression assays. We developed a classifier using the Banff-Human Organ Transplant (B-HOT) gene panel extracted from a historical Molecular Microscope® Diagnostic system (MMDx) microarray data set.

Methods: Gene expression data (GEO: GSE98320) from 1208 kidney transplant biopsies was used to develop a classifier with genes that matched those from the B-HOT panel. Tree-based models, random forest and XGBoost, were trained to predict kidney transplant biopsy Banff categories, including non-rejection, antibody-mediated rejection (ABMR), T cell–mediated rejection (TCMR), and mixed rejection (ABMR+TCMR). Performance was evaluated using nested cross-validation.

Results: A multilabel random forest model trained on B-HOT panel genes achieved a mean accuracy of 76.2%. However, both classifiers could not predict ABMR+TCMR Banff category. Accuracy was improved to 77.1% using only the MMDx genes included in the B-HOT panel. Classification of rejection versus non-rejection and rejection sub-types separately vastly improved overall performance for both random forest and XGBoost. The best performance was achieved by XGBoost using the B-HOT panel and synthetic minority oversampling for ABMR+TCMR samples, with an accuracy of 93.6% for non-rejection and 95% for rejection subtypes. Balanced accuracies of prediction were 95.9% and 90.8% for ABMR and TCMR, respectively.

Conclusion: A kidney transplant biopsy classifier using molecular data of a historical data set obtained for the MMDx was developed using only the genes included in the B-HOT panel. While comparison of performance should be treated with caution due to differences in validation sets, the performance of this classifier was higher compared to MMDx. This work is one step closer to the development of a decentralized kidney transplant biopsy classifier that is effective on data derived from different gene expression platforms.

OFP-17-011

Kidney biopsy findings in SARS-Cov2 infected patients: a single center case series of post/co-Covid glomerulopathies & kidney injury

M. Bugdayci Uner*, A. Saglam Ayhan, MD

*Department of Pathology, Hacettepe University Faculty of Medicine, Turkey

Background & objectives: Covid19 is a multisystem disease, which may also present with acute tubular injury. Besides, glomerular pathologies associated with Covid-19 can be seen as a “second-hit” phenomenon. Herein, we present 8 post/co-covid cases with glomerular, tubular and vascular injury.

Methods: H&E, JMS, PAS, PAMS, MTC and immunofluorescent slides (IgG, IgA, IgM, C3, C4, C1q, Kappa and Lambda) of 8 cases with kidney dysfunction after or during Covid19 proven by PCR positivity were re-evaluated. Then, clinical findings (such as proof of covid19 pneumonia via thorax CT, interval between beginning of Covid19 symptoms and kidney dysfunction etc) were correlated with histopathological findings.

Results: The mean age of our cases were 64,1 yrs (27-90), and included 4 female and 4 male. Two patients (61 and 71) died while hospitalized in intensive care unit. Six cases had covid19 pneumonia, almost all cases had elevated serum creatinine levels, while some showed proteinuria. Two cases were post-transplant while others were native biopsies. Kidney biopsy findings demonstrated 3 main groups: 1) Post-covid glomerulopathies with immune complexes: Anti-GBM disease (1 case), IgA nephropathy (2 cases), Post-infectious glomerulonephritis (1 case), IgG-kappa and C3-associated glomerulonephritis (1 case). 2)Post-covid kidney findings without immune complexes: ANCA-associated pauci-immune crescentic necrotizing glomerulonephritis (1 case), Acute tubular injury (1 case) 3) Co-covid intimal endarteritis (1 case).

Conclusion: Even though, acute tubular injury is the most common histopathological finding in kidney involvement of covid19, viral induced glomerulopathies must be kept in mind in SARS-Cov2 infection. Especially in post-covid period, glomerulopathies associated with Covid-19 can be seen as a “second-hit” phenomenon. Indirect damage seems to have a role in endothelial injury via coagulation mechanisms, and immune system-inflammation pathways (including complement). Much more remains to be learned to elucidate the exact mechanisms causing acute kidney injury in patients with COVID-19.

OFP-18 | Neuropathology

OFP-18-001

No brachyury expression in atypical teratoid/rhabdoid tumour

H.G. Yeter*, B. Babaoglu, K. Kösemehmetoğlu, F. Soylemezoglu

*Hacettepe University, Turkey

Background & objectives: Atypical teratoid/rhabdoid tumour (AT/RT) shares some morphological, immunohistochemical, and molecular features with poorly differentiated chordoma (PDC). Here, we investigate the expression of brachyury, which is known as a sensitive and specific marker for notochordal differentiation, in AT/RT.

Methods: Forty-four tumour samples from 40 patients, diagnosed as AT/RT between 2001-2020 were included in 3-mm tissue microarrays. Immunohistochemical stainings for INI1 and two different clones of brachyury (Abcam-ab209665 and Santa Cruz-A4) were performed. Nuclear staining is counted as positive for both stains.

Results: Twenty-three patients were male and 17 were female. Patients were aged 0 to 15 years (mean:2,85 years and median:1 year). Twenty-seven of 44 tumour samples were located supratentorial; 15 were infratentorial and 2 were spinal. Three cases (7,5%) were found to retain INI1 expression. Two cases (4,5%), located at dorsal sellar region and clivus, were found to be positive with brachyury, one of which demonstrated diffuse and strong positivity, while the other showed focal (30%) expression. These 2 cases were reclassified as PDC. Two different clones of brachyury demonstrated similar results for all cases.

Conclusion: AT/RT’s one of the most challenging differential is PDC, a recent entity characterized by sheets of epithelioid/rhabdoid cells with accompanying inflammation, INI1 loss and brachyury positivity, when located particularly in the infratentorial and spinal region. Brachyury is a reliable marker in differentiating AT/RT from PDC, knowing that none of the unquestionable supratentorial AT/RTs in our series showed brachyury expression.

OFP-18-002

Elesclomol-induced increase of mitochondrial reactive oxygen species impairs glioblastoma stem-like cell survival and tumour growth

M. Martini*, M. Buccarelli, T. Cenci, G. D'Alessandris, P. Matarrese, M. Biffoni, R. Pallini, L. Ricci-Vitiani

*Fondazione Policlinico Universitario A. Gemelli, IRCCS, UCSC, Italy

Background & objectives: It has been widely demonstrated glioblastoma stem-like cells (GSCs), a subpopulation of tumour cells endowed with stem-like propertiesis responsible for tumour maintenance, progression and contribute to GBM-associated neovascularization processes, through different mechanisms including the trans-differentiation into GSC-derived endothelial cells (GdECs).

Methods: In order to identify druggable cancer-related pathways in GBM, we assessed the effect of a selection of 349 compounds on both GSCs and GdECs. As a result of this screening, we selected elesclomol (STA-4783) as the most effective agent in inducing cell death on both GSC and GdEC lines tested.

Results: Elesclomol has been already described to be a potent oxidative stress inducer. In depth investigation of the molecular mechanisms underlying GSC and GdEC response to elesclomol, confirmed that this compound induces a strong increase in mitochondrial reactive oxygen species (ROS) in both GSCs and GdECs ultimately leading to a non-apoptotic copper-dependent cell death. Finally, we used our experimental model of mouse brain xenografts to test the combination of elesclomol and temozolomide (TMZ) and confirmed their efficacy in vivo.

Conclusion: In conclusion we think that our results support further evaluation of therapeutics targeting oxidative stress such as elesclomol with the aim of satisfying the high unmet medical need in the management of GBM.

Funding: This research was funded by Italian Ministry of Health, (RF-2016-02361089 to LRV) and AIRC (IG 2014 Id.15584 to LRV).

OFP-18-003

Adult diffuse gliomas in the era of morphomolecular diagnosis – lessons from a 2-year experience in a Portuguese reference centre

T. Maia*, D. Pereira, M. Mafra

*IPO Lisboa, Francisco Gentil, Portugal

Background & objectives: IDH1/2-mutations are frequent in adult diffuse gliomas (ADG), particularly in younger patients (≤55yo). Both IDH-mutation-status and 1p/19q-codeletion-status are strong prognostic/therapeutic stratifiers. We aimed to evaluate: a)prevalence of IDH-mutations across all age groups of ADG; b)morphophenotypic correlations with IDH-mutation-status and 1p/19q-codeletion-status.

Methods: All consecutive cases of ADG with concurrent molecular testing for IDH-mutation/ 1p/19p-codeletion diagnosed between March 2019 and February 2021 were reviewed and morphologically classified: a)pure astrocytic (PA); b)oligoastrocytic/ambiguous (OA); c)oligodendroglioma-like (ODG). An immunohistochemical (IHQ) panel was applied to all cases: IDH1-R132H (iIDH), ATRX and p53. IDH1/2 molecular testing was performed by PCR-based sequencing. 1p/19q-codeletion was evaluated by FISH.

Results: A total of 153 cases were reviewed: 34 were IDH-mutated (n=16 PA, n=3 OA, n=15 ODG), 27 in younger adults (prevalence=43.6%), 7 in older adults (prevalence=7.7%, the oldest with 72yo) (n=1-PA non-1p/19q-codeleted/n=6 OA/ODG-1p/19q-codeleted); 31 (91.2%) IDH-mutations corresponded to IDH-R132H form, 3 to the IDH-R132S mutation variant.

iIDH-positivity was 100% specific and 100% sensitive for IDH1-R132H mutation. The patterns iIDH-negative/ATRX-negative (n=6) and OA/ODG-morphology/ATRX-positive/p53-negative (n=15) were 100% sensitive to detect potential IDH mutations, iIDH-negative/ATRX-negative pattern with overall specificity=50% and specificity=100% in non-midline ADG. OA/ODG-morphology-ATRX-positive/p53-negative pattern had sensitivity=100% and specificity=93.3% in predicting 1p/19q-codeletion. PA, ATRX-negativity and p53-positivity were mutually exclusive with 1p/19q-codeletion. PA morphology-iIDH-negative/ATRX-positive (n=117) and OA-iIDH-negative/ATRX-positive/p53-positive (n=2) were IDH-wildtype lacking 1p/19q-codeletion.

Conclusion: Prevalence of IDH-mutations in ADG with astrocytic morphophenotypes (PA, iIDH-negative/ATRX-negative, OA-iIDH-negative/ATRX-positive/p53-positive) was lower than expected for younger adults, rare in older adults as expected. Prevalence of R132H mutation was similar to the literature.

IDH-mutation-status is reliably predicted/identified combining morphology and immunophenotype, regardless of age.

1p/19q-codeletion is reliably predicted/excluded by specific morphophenotypes.

The majority of ADG (89,5%) don´t need molecular testing for IDH-mutations/ 1p/19q-codeletion, an important rationale to preserve tissue in the foreseeable era of deeper molecular testing for targeted therapy.

OFP-18-004

Prognostic factors of the rare papillary tumour of the pineal region: a systematic review and analysis

B. Montenegro, J.P. Dinis, N.J. Lamas*

*Anatomic Pathology Service, Department of Pathology, Centro Hospitalar e Universitário do Porto, Portugal

Background & objectives: Tumours of pineal region are rare, representing less than 1% of all intracranial tumours in adults. Here, we aimed to compile current knowledge on the Papillary Tumour of the Pineal Region (PTPR) to identify factors that influence death and recurrence.

Methods: A search was performed in the databases PubMed, Scopus, Web of Science and Google Scholar using the keywords “papillary pineal tumour” and “papillary tumour of the pineal region”. 169 potentially relevant articles were identified. The most relevant inclusion criteria were the presence of histopathological and immunohistochemistry characterization and information on tumour size. Exclusion criteria comprised systematic reviews and Radiology-oriented articles.

Results: Twenty articles were included in the final analysis. A database was created containing information on patient characterization, treatment, follow-up, histopathological and immunohistochemistry data. Thirty patients were included, between 1 and 70 years, 14 of which were females and 16 males. The descriptive and analytical statistics performed showed that the presence of areas of necrosis, the expression of cytokeratins, higher proliferative index and mitotic activity are associated with recurrence.

Conclusion: In patients with TPRP, the presence of necrosis seems to be the factor that most influences the recurrence of the neoplasia, an aspect that should be considered in the decision to start more aggressive therapies earlier. This study has limitations conditioned by the reduced number of cases published in the medical literature, so more comprehensive studies will be needed to confirm these findings.

OFP-18-005

Prognostic significance of the sarcomatous component in gliosarcomas: clinicopathological and prognostic analysis of 25 cases

E. Gun*, F. Cakalagaoglu, A. Kahraman Akkalp, I.E. Sevin

*Izmir Katip Celebi University, Turkey

Background & objectives: Gliosarcoma is a rare central nervous system neoplasm with biphasic glial and mesenchymal components.It is accepted as a variant of glioblastoma multiforme(GBM) in the World Health Organization 2016 classification. We aimed to evaluate the clinicopathological and prognostic features of gliosarcomas.

Methods: All patients operated by our neurosurgery clinic between January 2007 and January 2021 were retrospectively analysed. The demographic, clinical, radiological, histopathological, immunohistochemical and molecular data of 25 patients diagnosed with gliosarcoma were retrospectively analysed and statistically evaluated. The sarcomatous component was grouped depending on the histopathological appereance and prognostic studies were performed regarding these groups.

Results: There were 986 central nervous system tumours operated in our hospital within 14 years. GBMs(n=232) constituted 23.5% wheras gliosarcomas were 10.7% of GBMs (n=25,mean age 57,3,M/F:17/8). The most common localization was the temporal region. The mean tumour diameter was 5,7(2-9)cm. The primary tumour was gliosarcoma in 12 patients,and it developed secondary to GBM in 13 patients. The sarcomatous component was grouped as conventional spindle cell sarcoma(n=13),pleomorphic sarcoma containing pleomorphic cells(n=6) and high-grade sarcoma with heterologous differentiation(n=6). Recurrence was seen after an average of 3,6(±3,1)months. The mean survival time was 4,8 months,those with a previous diagnosis of GBM had shorter survival(p=0.028)and those with heterologous components in sarcoma had longer survival. The shortest survival was in sarcoma containing pleomorphic cells(p=0.024).

Conclusion: Gliosarcomas are extremely rare tumours which are only available as case reports in the literature. Our study contributes to the literature in terms of incidence and histopathological differentiation data. Gliosarcomas should be diagnosed with a careful histopathological examination and differentiated from entities such as epithelioid sarcoma and carcinoma. When mesenchymal differentiation is seen,the entire tissue should be examined and the glial component should be searched, and molecular studies such as IDH,as well as PTEN, TP53, TERT mutations and CDKN2A deletion should be performed.

OFP-18-006

The immunohistochemical expression of Serin and Arginine-Rich Splicing Factor 1 (SRSF1) is helpful in distinguishing diffuse astrocytomas and oligodendrogliomas from other gliomas

G. Broggi*, F. Certo, R. Altieri, G. Barbagallo, R. Caltabiano

*University of Catania Section of Anatomic Pathology, Italy

Background & objectives: The aim of this study was to investigate the immunoexpression of SRSF1 in a series of 102 cases of diffuse and circumscribed adult gliomas, emphasizing the potential diagnostic role of this protein in the differential diagnosis of brain tumours.

Methods: 42 IDH-wild type glioblastomas (GBMs), 21 IDH-mutant and 1p/19q codeleted oligodendrogliomas, 15 ependymomas, 15 pilocytic astrocytomas (PAs), 5 sub-ependymal giant cell astrocytomas (SEGAs) and 4 pleomorphic xanthoastrocytomas (PXAs) were retrospectively retrieved from the neuropathological archive of our Institution and stained with anti-SRSF1 immunohistochemically antibody. The presence of brown chromogen within the cell nuclei was interpreted as positive SRSF1 staining.

Results: Most GBMs (34/42; 81%), oligodendrogliomas (15/21; 71%), SEGAs (4/5; 80%) and PXAs (3/4; 75%) showed strong SRSF1 immunoexpression, while no detectable staining was found in the majority of ependymomas (13/15; 87%) and PAs (10/15; 67%); the remaining ependymoma and PA cases exhibited weak and focal SRSF1 immunoexpression in 2/15 (13%) and 5/15 (33%) cases, respectively. Interestingly, no high SRSF1 immunohistochemical expression was found in any case of PA or ependymoma. Based on our findings, SRSF1 was a reliable immunomarker, both in confirming the diagnosis of diffuse astrocytoma and oligodendroglioma and in excluding other neuropathological entities, such as ependymomas and PAs.

Conclusion: Apart from the morphological and molecular features of gliomas, there are currently no specific immunohistochemical markers for this heterogeneous group of tumours: thus, there is the need to identify more specific and useful immunomarkers to distinguish each histological subtype from the others. The present study strongly emphasizes the role of SRSF1 as a new and promising immunomarker of diffuse gliomas and suggests that SRSF1 can be exploitable as a diagnostic adjunct to conventional markers in neuropathological daily practice.

OFP-18-007

Histone 3 thrimetilated in lysin 27 (H3K27me3) immunostaining is a diagnostic and prognostic marker in diffuse gliomas with mixed or oligodendroglial morphology

S. Ammendola*, N. Caldonazzi, M. Brunelli, P.L. Poliani, G. Pinna, F. Sala, C. Ghimenton, A. Scarpa, V. Barresi

*Department of Diagnostics and Public Health, Section of Anatomic Pathology, University of Verona, Italy

Background & objectives: Surrogate immunohistochemical markers for 1p/19q codeletion could simplify the differential diagnosis between astrocytoma and oligodendroglioma. H3K27me3immunohistochemical loss has been associated with 1p/19qcodeletion.

We analysed the diagnostic and prognostic value of H3K27me3 immunostaining in gliomas with oligodendroglial or mixed morphology.

Methods: H3K27me3 immunoexpression was analysed in 69 diffuse gliomas with oligodendroglial or mixed morphology. All cases were immunostained for IDH1 R132H, ATRX and P53.

IDH1 R132H-negative cases underwent IDH1/2 gene sequencing. The presence of 1p/19q codeletion was investigated with FISH or PCR-based assays.

Statistical analyses were performed to assess the correlation between H3K27me3 staining and clinical-pathologic data.

Results: H3K27me3 was lost in 58/60 oligodendroglial tumours with retained (n=47) or non-conclusive (n=11) ATRX staining, 3/6 astrocytic IDH-mutant with ATRX loss and 3/3 IDH-wt tumours. H3K27me3 was retained in 2/60 oligodendroglial tumours, that also retained ATRX, and in 3/6 astrocytic IDH-mutant tumours, two of which had lost and one retained ATRX.

H3K27me3 retention was associated with a significantly shorter recurrence-free survival (P< 0.0001), independently from IDH mutational status, histological grade or 1p/19q codeletion.

Conclusion: A diagnostic workflow including H3K27me3 immunostaining, after the assessment of IDH1/2 mutational status and ATRX staining, is useful to reduce the number of diffuse gliomas that necessitate 1p/19q codeletion testing.

According to this algorithm, gliomas IDH-wt and IDH-mutant with ATRX loss are classified astrocytic; gliomas IDH-mutant with ATRX retention and H3K27me3 loss are classified oligodendroglial; only gliomas IDH-mutant with retained or non-conclusive ATRX and retained H3K27me3 necessitate 1p/19q codeletion testing. H3K27me3 loss is associated with longer recurrence-free survival.

OFP-18-008

Prognosis of patients with IDH-wildtype and IDH-mutant diffuse gliomas: data from the King Hussein Cancer Center (2014–2019)

M. Al-Hussaini*, S. Al-Ghnimat, H. Sultan, J.Z. Amarin

*King Hussein Cancer Center, Jordan

Background & objectives: Mutations in isocitrate dehydrogenase (IDH) signal a better prognosis in diffuse astrocytic and oligodendroglial tumours. Our aim was to study the prognosis of patients with IDH-wildtype and IDH-mutant diffuse gliomas at the King Hussein Cancer Center.

Methods: We performed a retrospective chart review of all Jordanian patients with diffuse gliomas who were managed at our center (2014–2019) and underwent IDH1 (R132H) immunostaining. We included the following entities: diffuse astrocytoma, anaplastic astrocytoma, glioblastoma, oligodendroglioma, and anaplastic oligodendroglioma. We used the Kaplan–Meier method to estimate the overall survival rates and the log-rank test to perform pairwise comparisons.

Results: We included 181 patients. Glioblastoma was the most common entity (n = 104), followed by anaplastic astrocytoma (n = 29), diffuse astrocytoma (n = 24), oligodendroglioma (n = 15), and anaplastic oligodendroglioma (n = 9). IDH-wildtype tumours outnumbered IDH-mutant tumours 112 (61.9%) to 69 (38.1%). IDH mutation was most common in oligodendroglioma (93.3%), followed by anaplastic oligodendroglioma (77.8%), diffuse astrocytoma (62.5%), anaplastic astrocytoma (51.7%), and glioblastoma (17.3%). IDH status statistically significantly stratified the overall survival of the full cohort (p < 0.001), patients with any astrocytic tumour (p < 0.001), patients with a grade II or III astrocytic tumour (p = 0.035), and patients with glioblastoma (p = 0.049).

Conclusion: IDH mutation signals a better prognosis in patients with a diffuse glioma. This finding is concordant with the published international literature.

OFP-19 | Ophthalmic Pathology

OFP-19-001

Lacrimal gland pleomorphic adenoma: factors leading to recurrence and malignant potential

S. Flanagan*, S. Reilly, R. Ellard, N. Walsh, R. Khan, S. Kennedy

*Histopathology Department, St Vincent's University Hospital, Dublin, Ireland

Background & objectives: Lacrimal gland pleomorphic adenomas (LGPA) can undergo malignant transformation, most often in recurrent cases. Complete excision is thus the recommended definitive diagnostic/therapeutic approach when clinically/radiologically suspected.

This paper will investigate the potential factors associated with LGPA recurrence and malignant transformation.

Methods: A retrospective review of histologically confirmed LGPA cases occurring between September 1975 and January 2021 (46 years) in a national tertiary referral centre for ophthalmic pathology was undertaken. Where residual/recurrent LGPA or malignant transformation was identified, patient records were accessed and further information including; socio-demographics, presenting symptoms, diagnostic procedures, radiology and clinical course was analysed.

Results: A total of 13 cases of LGPA were identified. Recurrent LGPA occurred in 3 patients, no cases of malignant transformation were reported. The recurrence time for LGPA ranged from 6 months to 15 years post initial diagnosis. Recurrence occurred in 2 males and 1 female, all were Irish Caucasians with ages ranging from 13 to 72 at the time of first biopsy. The initial diagnostic procedure in all recurrences was incisional biopsy. The reasons for incisional biopsy versus the recommended primary en bloc resection included clinical uncertainty and broad radiologic differential. No recurrences were identified in LGPA cases which had undergone outright complete excision.

Conclusion: LGPA should be considered as a potential diagnosis in lacrimal lesions at all ages. In cases of clinical or radiological ambiguity, second opinion from a specialist centre should be sought. Where necessary, fine needle aspiration cytology is preferable to incisional biopsy due to the associated potential for tumour displacement and subsequent increased risk of recurrence. In situations where incisional biopsy is undertaken, the suture track should be marked to facilitate identification and removal of the entire track during subsequent resection.

OFP-20 | Other Topics

OFP-20-001

Quick sectioning-free H&E imaging of bulk tissue using multiphoton microscopy

M. Strauch*, J.P. Kolb, C. Rose, N. Merg, J. Hundt, C. Kümpers, S. Perner, S. Karpf, R. Huber

*Medical Laser Center Lübeck, Germany

Background & objectives: Labour and time-intensive paraffin sectioning is the foundation of today’s routine pathology workflow. To accelerate this process, we create H&E images from bulk fresh or formalin-fixed tissue without sectioning using a home-built multiphoton microscope based on fibre laser technology.

Methods: To evaluate whether our multiphoton microscopy technique can provide a fast alternative to paraffine or frozen sectioning, we compare images of our system using H&E-stained formalin-fixed tissue as well as acridine orange and sulforhodamine 101-stained fresh tissue to classical formalin-fixed paraffin embedded sections.

Results: Our multiphoton microscope can acquire images of bulk acridine orange and sulforhodamine 101 stained skin and kidney samples within less than 1 hour. We gross the tissue block and stain it for 10 min without any further processing. Afterwards the tissue is scanned by the microscope and converted into a digital H&E image. The digital image can now directly be analysed by a pathologist. Additionally, we compared multiphoton microscope images of formalin-fixed H&E-stained tissue to paraffin-embedded sections of the same block to assess the quality of our technique.

Conclusion: We create H&E-like images without sectioning the tissue using a home-built multiphoton microscope. Two different staining mechanisms have been tested to acquire high quality images. In the future, we want to further improve our measurement speed and start a clinical study on basal-cell carcinoma. The potential combination with other imaging modalities such as fluorescent lifetime imaging and the application of AI algorithms on the digital data might allow us to increase the diagnostic accuracy of our method.

OFP-20-002

Taking undergraduate pathology research education to the Cloud

D. Myoteri*, A. Burt, D. Tiniakos

*Department of Pathology, Aretaieion Hospital, Medical School, National and Kapodistrian University of Athens, Greece

Background & objectives: COVID-19 pandemic has created the largest disruption in education in human history. Quick and efficient modifications to teaching and assessment were devised to maintain biomedical education continuity. We created a virtual pathology research project for undergraduate (UG) biomedical sciences students.

Methods: The bespoke research project was based on fixed field images from 20 digitised human nonalcoholic fatty liver disease (NAFLD) biopsies (n=40, training set and n=60, test set). Students were trained using a web-based teleconference platform in four group sessions, followed by one-to-one meetings, and self-studied using the free LITMUS NAFLD Histopathology Atlas at the European Society of Pathology website (https://tinyurl.com/LITMUS-Histology).

Results: Inter-observer variability between 3 stage 3 UG students and three pathologists on semi-quantitative histological scoring of steatosis, lobular inflammation (LI), hepatocyte ballooning (HB) and fibrosis was assessed. The NASH CRN histological scoring system and Fleiss’s and Cohen’s kappa statistics were applied. Results were discussed during online adjudication meetings and multiple annotations were used on the images in difficult cases. Following training, steatosis was the feature with highest agreement (k=0.63) in the whole group, while moderate agreement was achieved for LI (k=0.52), fibrosis (k=0.57) and HB (k=0.46). All students efficiently prepared on time a 5,000-word dissertation, organized as an original research publication, and a power-point presentation required for project assessment.

Conclusion: Novel educational initiatives have been employed to sustain UG student theoretical and practical learning during Covid19 pandemic. We have successfully modified a “wet” UG pathology research project into a virtual “dry” project applying Cloud-based digital pathology imaging and providing online pathology training and feedback sessions using web-conference tools. Our methodology offers a digital alternative to laboratory-based research teaching in pathology and may be further improved for application in larger student groups.

OFP-21 | Paediatric and Perinatal Pathology

OFP-21-001

Placental and placental bed pathology caused by SARS-CoV-2

E. Rudenko*, E. Kogan, T. Demura, N. Trifonova, N. Zharkov, D. Protsenko, O. Lobanova

*Sechenov University, Russia

Background & objectives: The impact of coronavirus infection SARS-CoV-2 on pregnancy and perinatal outcomes is particular interest for obstetricians, paediatricians and other scientists. The aim of study was to reveal changes in the placenta and placental bed of women with confirmed SARS-CoV-2 infection.

Methods: The main group included 34 women (SARS-CoV-2 confirmed by real-time PCR), a comparison group included 15 healthy women. Histopathological examination of placenta and placental bed was carried out. Staining method was performed on serial sections of paraffin blocks with H&E. Immunohistochemistry with CD8 and CD3 was performed, as well as real-time PCR. Statistical processing by Fisher's test

Results: In the main group an increase of complications (anaemia (48%) and isthmic-cervical insufficiency (11.8%), preeclampsia (2.9%) and threatening premature birth (11.9%)) was found. Microscopic examination showed an increase in the incidence of maternal malperfusion (central infarctions (p = 0.00032), agglutination of villi (p = 0.00043), decidual arteriopathy (p = 0.00069), intervillous thrombi (p = 0.00005)) and foetal stromal-vascular lesions (obliterative angiopathy (p = 0.00033), chronic willitis (p = 0.00002), chronic chorioamnionitis (p = 0.00001), massive fibrinoid deposits in the uteroplacental region (p = 0.00001)). Biopsys of the placental bed showed foci of lymphohistiocytic infiltration and focal hemorrhages in the perivascular areas. Decidual arteriopathy was detected in 18 cases.

Conclusion: Changes in the placenta in women with confirmed SARS-CoV-2 infection in the third trimester of pregnancy are characterized by the development of maternal vascular malperfusion, chronic inflammation in the form of focal villitis and interillusitis, obliterative angiopathy and lesions of the decidual spiral arteries. These changes reflect an increased risk for transplacental transmission of the virus and can lead to long-term negative consequences for the foetus.

OFP-21-002

Impact of SARS-COV-2 on foetus and placenta of pregnant women affected by COVID-19. Study of 177 cases received during the pandemic

L. Naranjo Ruiz-Atienza*, A. Navarro Jiménez, J. Camacho Soriano, J. Hernández Losa, L. Cerro, I. Strohecker Santos, T. Moliné Marimon, S. Ramón y Cajal-Agüeras, M. Garrido-Pontnou

*Pathology Department, Vall d'Hebron University Hospital, Spain

Background & objectives: Placental pathology and vertical transmission in pregnant women infected by SARS-CoV2 has generated many reports with nonspecific or contradictory results. The objective is to identify histological and molecular findings of infected placentas and its impact on the course of pregnancy.

Methods: Placentas from 177 women infected with SARS-COV-2 were reviewed, 66 of them with active infection within 10 days prior to delivery and 111 with past infection beyond this period. Two foetal autopsies were submitted for pathological study. Placental infection was investigated by immunohistochemistry (IHC) in all cases, RT-PCR in 27 cases, and in situ hybridization (ISH) in 5 cases.

Results: Five placentas showed trophoblast necrosis with villous stroma preserved, collapse of the intervillous space, intervillous fibrinoid deposition and variable polymorphous inflammatory infiltrates. These 5 placentas were the only ones with SARS-CoV-2 infection identified by IHC and ISH (granular cytoplasmic villous trophoblast staining) and RT-PCR. These 5 cases with placental infection belonged to the group of pregnant women with active infection within 10 days prior to delivery. Two had focal lesions (<20%) and the other three, which resulted in stillbirth, showed diffuse lesions (> 80%). In two of the three deaths, an autopsy was performed and infection of the foetal tissues was not demonstrated by IHC.

Conclusion: Placental SARS-CoV-2 infection has a characteristic histological pattern with villous trophoblast necrosis, intervillous space collapse, and variable degrees of mixed inflammation and intervillous fibrinoid deposition. Placental infection can be confirmed by trophoblast cytoplasmic positivity with IHC and/or ISH for SARS-CoV-2. We propose the term "Diffuse Trophoblastic Damage" for extensive lesions, which can be the cause of foetal death due to placental insufficiency. In this study we have not been able to confirm the possible vertical transmission of the virus.

OFP-21-003

Diffuse trophoblast damage is the hallmark of SARS-CoV-2-associated foetal demise

A. Nadal*, M. Garrido, A. Navarro, J. Camacho Soriano, J. Hernández Losa, M. Sesé, S. Ramón y Cajal-Agüeras, J. Ferreres Piñas

*Hospital Clinic, Spain

Background & objectives: Placenta pathology in SARS-CoV-2 infected pregnancies seems rather unspecific. However, the identification of the placental lesions due to SARS-CoV-2 infection would be a significant advance in the management of these pregnancies and the identification of the mechanisms in vertical transmission.

Methods: The pathological findings in placentas delivered from 198 SARS-CoV-2 positive pregnant women were investigated for the presence of lesions associated with placenta SARS-CoV-2 infection. SARS-CoV-2 infection was investigated in placental tissues through immunohistochemistry and positive cases were further confirmed by in situ hybridization. SARS-CoV-2 infection was also investigated by RT-PCR in 33 cases, including all the immunohistochemically positive cases.

Results: Nine cases were SARS-CoV-2 positive by immunohistochemistry, in situ hybridization, and RT-PCR. These placentas showed lesions characterized by villous trophoblast necrosis with intervillous space collapse and variable amounts of mixed intervillous inflammatory infiltrate and perivillous fibrinoid deposition. Such lesions ranged from focal to massively extended in five cases, resulting in intrauterine foetal death. Two of the stillborn foetuses showed some evidence of SARS-CoV-2 positivity. The remaining 189 placentas did not show similar lesions.

Conclusion: The strong association between trophoblastic damage and placenta SARS-CoV-2 infection suggests that this lesion is a specific marker of SARS-CoV-2 infection in placenta. Diffuse trophoblastic damage, massively affecting chorionic tissue, can result in foetal death associated with COVID-19 disease.

OFP-21-004

Paediatric Hodgkin Lymphomas: a 10-year retrospective study from Coimbra

C. Faria*, A. Lai, B. Sepodes, G. Fontinha, M.J. Julião, M. Brito, R. Pina

*Centro Hospitalar e Universitário, Portugal

Background & objectives: Hodgkin lymphomas are common lymphoid neoplasms in children and adolescents worldwide. Two major types are recognized: classic Hodgkin lymphoma and nodular lymphocyte predominant Hodgkin lymphoma. The improved therapeutic approach, according to the correct diagnosis has led to a better prognosis.

Methods: From 2010 to 2020, there were 50 patients in total with histopathological diagnosis of Hodgkin lymphoma. The neoplasm had a clearly predilection for females, representing 62% of this retrospective study. The youngest case was diagnosed in a 3 year-old child and the oldest one in a 17 year-old adolescent.

Results: Classic Hodgkin lymphoma (CHL) represented 86% of cases while nodular lymphocyte predominant Hodgkin lymphoma accounted (NLPHL) for 10%. As for CHL, the vast majority were nodular sclerosis subtype, representing almost 96% of the total cases, with mediastinal involvement in almost all patients. There was also one case of mixed cellularity subtype and another of lymphocyte-rich CHL.

Two patients had recurrent disease, one died without response to bone marrow transplant and the other is currently being managed. Other two cases had its diagnosis reviewed and modified to B-cell lymphoma unclassifiable, one patient died due to progression of the disease and the other had an effective response to treatment.

Conclusion: Hodgkin lymphoma remains a neoplasia with great overall survival mainly at paediatric age. In our series, we conclude that it is necessary to review some cases when treatment is not effective because it might be present overlapping morphological and immunophenotype features that represent exceedingly difficult cases, resulting as B-cell lymphoma unclassifiable.

Recurrent disease and immunosuppression related to treatment also represented defiant cases in our study, however, the majority of patients remain relapse free after treatment, as expected.

OFP-21-005

Hepatoblastoma: a clinicopathological review of 17 cases from a single centre

J. Vaz Silva*, A. Coutada, J. Azevedo, D. Gigliano, R. Isidoro, A.L. Cunha, M. Afonso, L.P. Afonso

*Pathology Department, Portuguese Institute of Oncology - Porto FG, EPE (IPO-Porto), Portugal

Background & objectives: Hepatoblastoma, the most common primary malignant liver tumour in children, occurs mainly in the first three years of life, being associated with good survival rates. Since some subsets are not responsive to therapy, understanding predictors of tumour behaviour is mandatory.

Methods: Clinicopathologic features of 17 patients diagnosed with hepatoblastoma at Portuguese Oncology Institute of Porto (1999-2021) were reviewed. Material was composed of liver biopsies (n=14), and resection specimens (n=15) of primary tumour, as well as recurrence/metastatic resection specimens (n=10). Besides the descriptive results stated below, we further aim to correlate detailed histological findings with tumour behaviour and clinical outcome.

Results: Mean age at presentation was 2.78 years (range:0.35-8.1) and male:female ratio of 1.43:1. Most patients presented with abdominal mass, fever and/or abdominal pain. AFP was increased in the majority of cases. One with normal AFP was diagnosed with SCUD subtype. AFP decreased in all patients after treatment. Two carried APC gene mutations.

Hepatoblastomas were classified as epithelial (47%) or mixed epithelial and mesenchymal (53%). Most common patterns were foetal (29,4%) and mixed foetal and embryonal(37%); one SCUD and one macrotrabecular case were identified. 23.5% had extramedullary hematopoiesis. Heterologous elements present in 53%.

Metastasis occured in 23,5%; persistence in 5,8%. Survival rates were 92% at 5-years and 77% at 10-years follow-up.

Conclusion: Our data is in accordance with the literature, mostly demonstrating good survival rates, primarily due to therapeutical improvement. However, prognostic factors are still limited and mainly dependent on clinical and imagiology factors, with limited pathology input. Due to the rarity of disease, large multicentric collaborative studies are essential to identify potential molecular markers and pathological features that could predict tumour behaviour and improve even further therapy success or develop targeted therapy strategies.

OFP-21-006

Small-for-gestational age placentas – a clinical-pathological correlation

A. Lai*, M.B. Pimentão, G. Fontinha, B. Sepodes, J. Gama, J. Madeira, F. Ramalhosa, C. Faria, V. Almeida, R. Pina

*Pathology Department, Hospitais da Universidade de Coimbra, Centro Hospitalar e Universitário Coimbra, Portugal

Background & objectives: Small-for-gestational age placentas comprises placentas whose weight is below 10th percentile and they are correlated with various risk factors, most of them of maternal cause. Our work attempt to characterize the maternal clinical conditions and correlate with macroscopic/microscopic findings.

Methods: We retrospectively reviewed 418 singleton placentas from the last year, excluding those which weight was above 10th percentile or below 20+6 week gestational (WG) age. In those cases, we reviewed maternal history, macroscopic and histologic report and if there was an associated foetal autopsy.

Results: We obtained 137 small placentas (33%), with mean of 35WG age; eighteen with autopsies (11 stillbirths; 7 medical termination of pregnancy). Only 19 cases were concomitant with foetal weight <10thpercentile. Median maternal age was 32 years old (range 16-45 years old), most of them were healthy (52cases - 38%). The large number of cases were placentas with weight below 3rd percentile (102cases - 75%), the majority were healthy mothers followed by the group with multiple pathologies. The most frequent histologic features in the first group was maternal malperfusion (38%). Ten cases had no prior maternal history and no pathological findings; one was from an autopsy due to genetic alterations.

Conclusion: There are several well-known risk factors associated with small-for-gestational age placentas, the majority associated with maternal malperfusion; and our results are concordant. In 7.29% of the cases there were no clear reasons for placenta's low weight, not even maternal history, which suggests other factors may play a role. Despite some risk factors can be manageable, cases still exist with increased risk of foetal morbidity and foetal mortality.

OFP-21-007

Skin lesions in children: evaluation of clinicopathological findings

B. Calim Gurbuz*, B. Pehlivanoglu, T. Soylemez Akkurt

*Basaksehir Cam and Sakura City Hospital, Turkey

Background & objectives: Paediatric skin diseases may show various manifestations, occasionally affecting the patients’ quality of life. Histopathological examination may be required for the diagnosis. The aim of this study was to evaluate the spectrum of clinicopathological features in paediatric skin lesions.

Methods: A total of 180 biopsies of 171 consecutive patients were included. The clinicopathological findings were retrospectively evaluated and retrieved from clinical and pathological data. Neoplastic/proliferative lesions (NPLs) (n=97) were grouped per their origin while non-neoplastic (inflammatory) lesions (ILs) (n=83) were grouped based on their pattern. The clinical and histopathological characteristics were statistically analysed.

Results: 53% were male and median age was 10±4.9 y.o. (range 0-17). ILs mainly involved the head and neck while NPLs were predominantly located in lower extremity (p=0.001). The most common NPLs were benign nevus (23%, n=22) and pilomatrixoma (15%, n=15). The most frequent IL was spongiotic/psoriasiform dermatitis (45%). The mean diameter of NPLs was 2.3 cm, connective tissue/skin appendage tumours being the largest (p=0.02). Melanocytic lesions and cutaneous cysts were significantly more common in children >12 y.o. (p<0.05). Juvenile xanthogranuloma occurred only in children <6 y.o. Only one patient had histopathological findings suspicious for mycosis fungoides. The discordance rate between clinical and histopathological diagnoses was higher for ILs (32% vs.21%).

Conclusion: Although the spectrum of skin lesions is very broad in paediatric patients, most are benign in nature. The higher frequency of melanocytic and/or cystic lesions among children >12 years old may be attributed to increased self-care during puberty. Neoplastic/proliferative lesions seem to be more easily and accurately recognized by clinicians. However, multidisciplinary approach remains to be the optimal method in diagnosis of skin lesions among children, considering the relatively high rate of discordance between the clinical and histopathological diagnoses.

OFP-23 | Pulmonary Pathology

OFP-23-001

A multi-modality approach for biopsy-based diagnostic and prognostic prediction in early-stage lung adenocarcinomas

J. Wolf*, T. Trandafir, D. Mustafa, E. Andrinopoulou, M. Kros, A. Dingemans, A. Stubbs, J. von der Thüsen

*Department of Pathology, Erasmus MC, Rotterdam, The Netherlands

Background & objectives: Lung adenocarcinomas are variable in morphology and genetics. In resected tumours, these parameters correlate with prognosis and development of metastases. Deriving as much information from a biopsy as possible could facilitate an early stratification of patients for therapy and follow-up.

Methods: 200 patients with stage I and II adenocarcinomas were retrospectively included. Specimens (biopsies n=200; paired resections n=125) were evaluated for growth pattern, nuclear grade, fibrosis, inflammation and genomic alterations. Findings were compared using non-parametric testing for categorical variables. Model performance was assessed using the area under the curve for biopsies and resection specimens and overall and progression free survival calculated.

Results: The overall growth pattern concordance between biopsies and resections was 69.6%. Nuclear grade and degree of fibrosis correlated with different types of growth pattern and had higher scores in paired resections. EGFR mutations and MET exon 14 skipping mutations were mainly found in lepidic predominant tumours. The dominant growth pattern correlated with overall and progression free survival in resected adenocarcinomas but not in biopsies. We further demonstrated similar findings for nuclear grade and amount of fibrosis. Model performance for the prediction of overall and progression free survival using all available information from biopsy specimens only was poor and resulted in an average AUC of 0.58 and 0.57 respectively.

Conclusion: Our data confirm the prognostic relevance of growth pattern and nuclear grade in resected adenocarcinomas. We further demonstrated that the amount of fibrosis may predict overall and progression free survival. Contrary to our hypothesis, we could not confirm these findings for biopsy specimens. Combining all biopsy specimen information did not improve prediction of overall and progression free survival. For daily practice, more robust (bio)markers are needed in biopsies to predict prognosis and stratify patients for therapy and follow-up.

OFP-23-002

Different types of immune system regulations in severe Coronavirus disease 2019

H. Popper*, M. Zacharias, L. Brcic, L. Marsh, H. Lehrach, M. Schütte, G. Kwapiszewska, B. Timmermann, K. Kashofer, A. Nerlich, P. Regitnig, L. Kenner, K. Zatloukal

*Medical University Graz, Austria

Background & objectives: Coronavirus disease 2019 (Covid-19) is a severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2). While most patients exhibit mild or moderate symptoms, approximately 10-20 % progress to severe disease and 0.5-1 % of infected die.

Methods: To gain insight into the immune mechanisms underlying Covid-19 related lung damage a systematic, pathological and whole transcriptome analysis of autopsy materials was done collected from lung samples of 20 individuals, who died from Covid-19. These were compared to 13 patients from a different hospital, and reports on patients from South America for differences in the type of immune reaction.

Results: Distinct pathological and molecular signatures were observed, characterized by different stages of diffuse alveolar damage and disseminated intravascular coagulation with hyperinflammation, enabling stratification of the deceased individuals. CD4+ lymphocytes predominated during the early inflammation stages, in part expressing a memory signature. Natural killer cells (NK) and B lymphocytes were absent. Upregulation of the JAK3-STAT1-cGas-Sting-IL6 pathway was identified. This pathway upregulates class one interferons, and prolongs inflammation, and can activate coagulation by platelets. Genes involved in enhanced production of cGAS and stability of cGAS and STING were upregulated in Covid-19 cases. Downregulation of cytokines regulated by vitamin D (VitD) was also found, pointing to a potential role for VitD deficiency.

Conclusion: This integrated, multi-tiered analysis of autopsy materials provides insight into the lethal manifestation of Covid-19. It allowed to separate patients prone to disseminated intravascular coagulation from those with a classical respiratory viral pneumonia such as SARS-Cov1.

OFP-23-003

EGFR-mutated non-small-cell lung cancer transformation into small-cell lung cancer after tyrosine kinase inhibitors: let us think about liquid biopsy!

F. Pezzuto*, F. Fortarezza, F. Lunardi, V. Tauro, S. Frega, G. Pasello, F. Calabrese

*University of Padova, Italy

Background & objectives: Tirosine kinase inhibitors (TKI) are employed extensively in mutant non-small cell lung cancer (NSCLC), showing an indisputable benefit on tumour response. However, disease progression always occurs after approximately 9–12 months of treatment due to different mechanisms of resistance.

Methods: Herein, we describe two cases diagnosed as lung adenocarcinoma harbouring epidermal growth factor receptor (EGFR) mutations and treated by TKI with clinical benefit for a short time. In each case, liquid biopsy and subsequent transbronchial biopsy performed at the time of disease progression were processed by molecular analysis.

Results: CASE 1: A 39-year-old male nonsmoker with lung adenocarcinoma, harbouring an EGFR exon 19-deletion mutation was treated with Erlotinib. At recurrence after two years, a liquid biopsy detected the T790M mutation, switching the treatment to Osimertinib. After two months of unresponsiveness to Osimertinib, a re-biopsy was carried out. CASE 2: A 63-year-old female nonsmoker with lung adenocarcinoma, harbouring an EGFR exon 19-deletion mutation, was treated with Osimertinib. After a short period of clinical benefit, the patient underwent liquid biopsy and an EGFR wild type was found without any resistant mutant form. The mass was then re-biopsied. In both cases, the re-biopsy showed a switch to small cell lung carcinoma (SCLC).

Conclusion: Several mechanisms of resistance can affect TKI treatment, most commonly the acquisition of new mutations that overcome and/or bypass the inhibition of the specific molecular pathway and/or the histological transformation into more aggressive forms (e.g. SCLC). At the present time, “tissue is the solution”: histological analysis should be considered the first choice, whenever possible. Currently, liquid biopsy is indeed unable to detect any histotype switch thus delaying alternative treatments.

OFP-23-004

Oncogene driver testing in surgically early/locally advanced non-small-cell lung cancer: a single centre experience

F. Pezzuto*, F. Lunardi, F. Fortarezza, M.J. Acosta, M. Lorenzi, E. Faccioli, F. Rea, G. Pasello, F. Calabrese

*University of Padova, Italy

Background & objectives: Oncogene driver screening in advanced non-small-cell lung cancer (NSCLC) is a standard in practice in molecular pathology. Herein, we describe our experience of biomarker screening in surgically resected early/locally advanced NSCLC, whose molecular status is presently largely unknown.

Methods: The study included naïve surgically resected NSCLC cases consecutively recruited at the University Hospital of Padova (from 2017 to 2018; adenocarcinoma, stage I-IIIA). Must oncogene drivers, EGFR gene alterations, ALK/ROS1 translocations, and PDL-1 tissue expression were analysed in all cases. After surgery patients were treated with adjuvant radiotherapy and/or chemotherapy as opportune. Data on follow-up and treatments were collected.

Results: Ninety-five cases (55 males, 40 females, median age: 70 years) were studied. Four cases were ALK translocated (4%). Eighteen cases (19%) showed EGFR gene alterations in exons 18 (1 case), 19 (9 cases), 21 (6 cases), and in both 18 and 20 (2 cases). In 6 of them (30%) PD-L1 was positive (tumour proportion score >1%). At the average follow-up (45 months), 31 patients (33%) showed an adverse event: death in 16 (17%) cases and disease recurrence in 15 (16%) cases, also in stage I (13 out of 31, 42%). Four of them (13%) had an oncogene driver alteration.

Conclusion: Molecular analysis of oncogene drivers in surgically resected NSCLCs, whose incidence is similar to that of advanced stages, will be an additional important task for pathologists. This is reinforced by successful data obtained from the recent trial that demonstrated a benefit of adjuvant target therapy in completely resected EGFR mutation-positive NSCLCs (Wu et al, NEJM, 2020). Oncogene driver alterations and PDL-1 analysis in resected NSCLC may allow a better prognostic stratification, ensuring the administration of the most effective targeted treatments.

OFP-23-005

Lower gene expression of angiotension-converting enzyme 2 receptor in lung tissues of smokers with COVID-19 pneumonia

F. Lunardi*, F. Fortarezza, L. Vedovelli, F. Pezzuto, A. Boscolo, M. Rossato, R. Vettor, A.M. Cattelan, C. Del Vecchio, A. Crisanti, P. Navalesi, D. Gregori, F. Calabrese

*University of Padova, Italy

Background & objectives: Angiotensin-converting enzyme 2 (ACE-2) is the main cell entry receptor for SARS-CoV-2 and plays a critical role in causing COVID-19. The role of smoking is controversial, thus we correlated lung ACE-2 expression with several data to explore susceptibility to infection.

Methods: This is a retrospective observational study on 29 consecutive COVID-19 laboratory-confirmed autopsies performed at the University Hospital of Padova from March to October 2020. SARS-CoV-2 genome and ACE-2 mRNA expression were evaluated by Real-Time polymerase chain reaction in lung tissue samples obtained from all patients and correlated with several clinical/pathological data with main focus on smoking habit.

Results: Smoking habit was shown to be less frequent in high than low ACE-2 expressors (14% vs 67%, p=0.014). Bayesian logistic regression including smoking, age, gender, hypertension, and virus quantity confirmed that smoking was the most probable risk factor associated with low ACE-2 expression. A direct linear relation was found between viral quantity and ACE-2 expression (p=0.028). No other significant differences were found when ACE-2 expression was correlated with remaining clinical data. Finally, considering morphological features, high ACE-2 expressors showed more frequently a prevalent pattern of vascular injury than low expressors (56% vs 31%, p=0.049).

Conclusion: In conclusion, ACE-2 levels were decreased in the lung tissue of smokers with severe COVID-19 pneumonia. These results point out complex biological interactions between SARS-CoV-2 and ACE-2 particularly concerning the aspect of smoking habit and need larger prospective case series and translational studies.

Funding: This research was partially supported by a fellowship from the University of Padova/Intesa San Paolo Vita bank (2020A08).

OFP-23-006

Forms and stages of progression of pulmonary pathology in novel SARS-COV-2 coronavirus infection

E. Kogan*, T. Demura, S. Demura, Y. Berezovskij

*Sechenov University, Russia

Background & objectives: Lungs are the main portal of entry for COVID-19.

Methods: Study was performed on lung tissue from 232 autopsy patients with COVID-19 confirmed by PCR during life and/or by examining paraffin blocks of lung tissue. Conducted macro-, microscopic and immunohistochemical (IHC) analysis (CD3, CD20, TLR4, TLR9, ki67, р6З, OCT4, ALDH1) revealed the particularities of pathological changes in the lungs.

Results: Morphological examination revealed diffuse alveolar damage (DAD) (in 86% of cases); disseminated coagulopathy in all cases with thrombosis or thromboembolism of the pulmonary artery and haemorrhagic infarcts and haemorrhages; lymphocytic alveolitis with concomitant vasculitis of medium- and small-calibre pulmonary arterial branches in 92 %, viral-bacterial pneumonia (20%), interstitial fibrosis (10%), and disregeneration changes of the lung epithelium. IHC showed high expression of CD3, CD20, TLR4, TLR9 in inflammatory infiltrate in all cases; low or negative expression of ki67, р6З, OCT4, ALDH1 in foci of disregeneration.

Conclusion: Discussed pathological processes in lung tissue may be considered as stages of COVID-19 progression. The process in the lungs can develop along three morphogenetic pathways, starting with the development of DAD or lymphocytic alveolitis, or coagulopathy. The latter variant of the onset of infection is most likely associated with intestinal portal of entry. Wherein lung damage is secondary, and develops after viremia, disseminated intravascular coagulation and cytokine storm.

OFP-23-007

Transthoracic fine needle aspiration and clot core biopsies of pulmonary spindle and mesenchymal lesions: a Pandora’s box

K. Kaur*, T. Patel, P. Trivedi

*Gujarat cancer and research institute, India

Background & objectives: Pulmonary spindle cell and mesenchymal lesions represent a significant group of heterogeneous neoplasms with differentials ranging from benign to malignant lesions. This study highlights the role of FNAC and clot core biopsy in diagnosis of spindle-cell lesions in lung.

Methods: Present study is a retrospective study in which lung FNA with spindle and mesenchymal cells from 2015-2020 were retrieved from cytopathology archives and reviewed. Granulomatous lesions, FNA from mediastinum and chest wall were excluded. In our institute, fine-needle aspiration (FNA) cytology was the first material available while final diagnosis was rendered on clot core and IHC.

Results: 60 cases of FNA lung having spindle and mesenchymal cells as key morphological feature were identified. Six (10.0%) benign and fifty-four cases (90%) malignancies including 23 primary and 31 metastasis on clot core and IHC. FNA was paucicellular in 12 cases, reported as benign in 8 cases and malignant in 52 cases. One case of pulmonary blastoma was reported as inflammatory pseudotumour on cytology, other case of chondrosarcoma was reported as chondroid tumour. Most common primary malignancies sarcomatoid carcinoma and most common metastasis was malignant peripheral nerve sheath tumour. A single case of alveolar soft part sarcoma, epitheloid sarcoma and neuroblastoma arising in a teratoma were also identified.

Conclusion: FNA along with clot core plays a pivotal role in the subsequent pathway taken for diagnostic or therapeutic management of these patients.

OFP-23-008

Interobserver concordance of PD-L1 clones SP263 and E1L3N in non-small cell lung carcinoma (NSCLC): two centre study

E. Bozkurtlar, D. Karaman*, Ş. Batur

*Marmara University School of Medicine, Department of Pathology, Istanbul, Turkey

Background & objectives: The use of PD-L1 immune-checkpoint inhibitors in NSCLC has marked an era. Testing for PD-L1 expression of NSCLC is widely used, there may be inconsistencies between different immunohistochemical assays, moreover, between different observers. In this study, we aimed to measure inter-pathologist variability.

Methods: Pathological specimens that were diagnosed with NSCLC between 2017-2021 and had enough tumour tissue to stain with two clones were included to study. According to the percentage of positive tumour cells detected in each PD-L1 clone , semi-quantitative scoring was performed by two pathologists individually and blindly. Cohen’s kappa analysis was performed to measure consistency between two pathologists, EB and SB.

Results: There were 19 female and 83 male patients, with an average age of 63.25 years. Of the 102 cases 47(46%) were small biopsy, 37(36,2%) as resection and 7(6,8%) as cytology. The distributions of SP263 and E1L3N scoring of EB and SB were as the following (respectively): for 1% cut-off negative n=15/18 and n=20/34 and positive n=87/84 and n=82/68, for 50% cut-off negative n=15/18 and n=44/62 and positive n=87/84 and n=58/40.

Interobserver agreement for the two clones, at 1% cut-off, agreement was 82,4%,for E1L3N and 93% for SP263, respectively (Cohen κ:0,55 and 0,76, respectively); at 50% cut-off, agreement was 91.2%and 86,3% for E1L3N and SP263, respectively (Cohen κ:0,81 and 0,72, respectively).

Conclusion: The highest interobserver variability was observed for the ≥1% cut-off for positivity in assessment of NSCLC tissues stained by E1L3N clone. We have shown a substantial to almost perfect interobserver agreement in evaluating PD-L1 using SP263 for any cut-off value, and a substantial agreement in evaluating PD-L1 using E1L3N clones when we used ≥50% cut-off for positivity.

OFP-23-009

MUC4 and GATA3 immunohistochemical staining in the diagnosis of sarcomatoid mesotheliomas: Case series of 5 patients with clinical and pathologic correlation, and literature review

P. Gil Bernabe*, J. Martín López, G. Silvestre Egea, J.L. Rodríguez Carrillo, D. García Fresnadillo, C. Salas Antón

*Hospital Universitario, Spain

Background & objectives: Diagnosing mesotheliomas is challenging, especially sarcomatoid subtype, which poses a differential morphological diagnosis with sarcomatoid carcinomas (SC) and sarcomas, and usually lacks positive effusions. GATA3 and MUC4 expression has been described as useful in the diagnosis of sarcomatoid mesothelioma (SM).

Methods: We studied 5 cases, previously diagnosed as SM based on clinical and pathological criteria, between 2014 and 2020. Confirmation was made with, at least two mesothelial markers (calretinin, WT1 or D2-40) and two epithelial markers (BerEP4 and MOC31) in addition to, GATA3 (clone L50-823), BAP1 (clone C-4), MUC4 (clone SP241, with external control), EMA, Desmin and CKAE1-AE3 on complete sections.

Results: All cases were male, with ages ranging between 56-84 years at diagnosis. Different presentation forms were seen: pleural masses (3), pleuro-pulmonary nodule (1) or pleural nodule (1) with combined hemothorax (1) or pleural effusion (4). None had positive pleural effusions. Diagnosis was made by transthoracic core needle biopsy (2) or videothoracoscopic biopsy (3).

Three showed focal positive immunostaining for epithelial markers (EMA or CKAE1-AE3) and two showed focal positivity or complete loss for mesothelial markers (calretinin, WT1, D2-40).

GATA3 expression was found in all cases (5/5). No obvious immunostaining for MUC4 could be demonstrated (0/5), while up to 40% of sarcomatoid carcinomas are described as MUC4 positive.

Conclusion: Several risk factors were identified, such as smoking history (4/5), prolonged asbestos occupational exposure (1/5) and working in construction (2/5). All SM (100%) expressed GATA3 staining (only focal and weakly in two of them), what suggests that GATA3 is a very sensitive immunohistochemical marker, for the integrated clinical-radiological diagnosis of these neoplasms. Negativity for MUC4 does not exclude sarcomatoid carcinoma, requiring additional techniques (BAP1, homozygous deletion of P16 / CDKN2A, GATA3) to confirm/rule out MS.

OFP-23-010

The bronchoalveolar lavage in COVID-19 acute respiratory failure: the role of pathologist

F. Fortarezza*, F. Pezzuto, F. Lunardi, A. Boscolo, N. Sella, E. Serra, P. Navalesi, F. Calabrese

*University of Padova, Italy

Background & objectives: The occurrence of respiratory superinfections represents an additional risk factor for fatal outcome in COVID-19 patients. In this study we evaluate the role of the cytological examination of the bronchoalveolar lavage (BAL) in a cohort of patients with severe COVID-19.

Methods: BAL from 10 mechanically ventilated patients were collected following one of these criteria: radiology discordant from typical COVID-19 pneumonia; immunosuppression; no improvement after 10 days of ventilation; microbiological tests suspected for superinfection. For each case the following parameters were evaluated: adequacy; quantification of the inflammatory cells and lipid-laden macrophages index (LLMI); presence of microorganisms, hyperplastic pneumocytes, erythrocytes, necrotic material, fibrin.

Results: Ten millilitres of liquid were used to prepare cytological smears and cytoblock. Nine out the ten samples were adequate (upper airway contaminants <7%). Fungal hyphae (two morphologically compatible with Candida spp and one with Aspergillus spp) were detected in three cases through the special stains (i.e. PAS, Grocott). The LLMI was high (300) in a patient in whom a lung aspiration was subsequently confirmed. The remaining cases showed variable increases in neutrophilic granulocytes, hyperplastic pneumocytes, fibrin or necrotic material. These latter features are compatible with diffuse alveolar damage, due to SARS-CoV-2 infection.

Conclusion: The COVID-19 pandemic still represents a worldwide sanitary challenge, particularly regarding the severe forms characterized by acute respiratory distress syndrome. The occurrence of respiratory superinfections represents an additional risk factor for fatal outcome. The cytological evaluation of the BAL could represent an important surrogate of biopsy to investigate pathological lesions of the deep lung compartment in these severely compromised patients.

OFP-23-011

PD-L1 expression in squamous cell lung carcinoma in small biopsy specimens

J. Džambas*, I. Aleksic

*Faculty of Medicine Military Medical Academy Belgrade, Serbia

Background & objectives: Programmed death ligand-1 (PD-L1) is a predictive marker for immunotherapy of non-small cell lung cancer, including squamous cell carcinoma (SqCC). The aim of this study is determining immunohistochemical PD-L1 expression in patients with SqCC in small biopsy specimens.

Methods: There were 50 patients in this retrospective study. All the patients were diagnosed SqCC on small biopsy specimens sampled during bronchoscopy and confirmed on histologic material after surgical resection. Small biopsy samples were stained immunohistochemically with PD-L1 clone 28-8 antibody. Membranous PD-L1 expression on tumour cells was evaluated and positivity was considered when expression was in more than 1% cells.

Results: Among patients 86% were male and 14% female. 52% were smokers, 30% were former and 18% were non-smokers. Small-biopsy samples of 26% patients were PD-L1 positive and 12% had histological type in surgical specimen with- and 14% without keratinization. Most of patients with PD-L1 positivity ,76.92% were male and 23.08% were female. The majority of patients were former smokers (53.85%), following smokers (30.77%) and non-smokers (15.38%). There was no statistically significant difference neither between gender (p=0.522) nor different histological types of SqCC (p=0.624) between patients with PD-L1 positive and negative specimens. There was statistically significant difference between smoking habits of patients with PD-L1 positive and negative specimens (p=0.042).

Conclusion: PD-L1 expression was positive in about one quarter of patients with squamous cell lung carcinoma. PD-L1 expression in squamous cell lung carcinoma is linked to smoking habits and has no connection neither with histological type in surgical specimens of tumour nor with gender.

OFP-23-012

Evaluation of STING immunohistochemistry as a potential biomarker to predict immunotherapy efficiency in lung non small cell carcinoma

L. Claude*, F. Guisier, F. Marguet, J. Sabourin, N. Piton

*Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Pathology, F76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France

Background & objectives: STING (STimulating INterferon Gene) plays a key role in anti-tumoral immune response. PD-L1 is an imperfect biomarker for immunotherapies. Our objective was to evaluate STING immunohistochemical expression in non small cell lung carcinoma as a biomarker to predict pembrolizumab efficacy.

Methods: We performed a retrospective study on 56 patients treated in our institution by pembrolizumab as first line monotherapy. These patients had a locally advanced or metastatic NSCLC with TPS PD-L1 > 50%. STING immunhistochemistry was evaluated on tumoral cells and on tumour infiltrating lymphocytes (TIL). Pembrolizumab efficiency was assessed using the CT scan for patient follow-up.

Results: STING expression by the tumoral cell was heterogenous: 21 samples dysplayed no STING expression, 3 dysplayed strong expression 32 weak to moderate. In most cases TIL dysplayed weak to moderate STING expression. We did not observe any statistically significant correlation between tumoral STING expression and clinical response to pembrolizumab. There was no correlation between TIL STING expression and clinical response. Importantly, according to current recommandations, all patients treated by pembrolizumab as first line monotherapy dysplayed high PD-L1 expression. This PD-L1 high immuno-expression in our patients could induce a bias explaining our results.

Conclusion: Although pre-clinical studies tend to show a correlation between STING expression by tumoral cells and clinical efficiency of immune check point inhibitors (ICI), we found no correlation between STING immunohistochemical expression and response to pembrolizumab. Considering, the small number of patients studied, enlarging this study to patient with other ICI treatment protocols could be interesting.

OFP-24 | Soft Tissue and Bone Pathology

OFP-24-001

Detection of MDM2 gene amplification on tissue microarray-based fluorescence in-situ hybridization (FISH) in well-differentiated and dedifferentiated liposarcomas, displaying a wide morphological spectrum: a validation study

B. Rekhi*, N. Karnik, O. Shetty, S. Patkar

*Tata Memorial Hospital, India

Background & objectives: Liposarcomas, including atypical lipomatous tumour(ALT)/well-differentiated liposarcomas(WDLPS) and dedifferentiated liposarcoma(DDLPS) display a histomorphological spectrum with their several diagnostic mimics. MDM2 gene amplification characterizes ALT/WDLPS and as well as DDLPS. This study was conducted to validate MDM2 gene testing in these tumours.

Methods: Twenty-eight cases, diagnosed as ALT/WDLPS(n=5) and DDLPS(n=23), along with 10 other tumours were tested for MDM2 gene amplification, using fluorescence in-situ hybridization FISH) on tissue microarrays (TMAs). Fourteen cases, diagnosed as ALT/WDLPS and DDLPS, along with 49 other tumours were tested for MDM2 (IF2 clone) immunostaining. Twenty tumours were tested for p16INK4a immunostaining.

Results: FISH was interpretable in 25(89.2%) cases. Among 20 cases diagnosed as DDLPSs, 19 displayed MDM2 gene amplification. Among 5 cases diagnosed as ALT/WDLPS, four showed MDM2 gene amplification. Finally, 19 cases were confirmed as DDLPS and 4 as ALT/WDLPS.

Furthermore, 7/19 cases, confirmed as DDLPS and all 4 cases as ALT/WDLPS, tested for MDM2 immunostaining, displayed its diffuse immunoexpression, while a DDLPS showed its focal immunostaining. None of the 49 controls displayed diffuse MDM2 immunoexpression. ALL 16 DDLPSs and 4 ALTs/WDLPSs displayed p16INK4a immunostaining. Sensitivity for diffuse MDM2 immunostaining was 87.5% and specificity was 100%. The sensitivity for MDM2 gene amplification was 94.7%. Sensitivity for p16INK4a was 100%.

Conclusion: This constitutes the first sizable study on MDM2 testing in ALT/WDLPS and DDLPS from our subcontinent, using TMAs. MDM2 gene amplification testing is the diagnostic gold standard for ALTs/WDLPSs and DDLPSs, particularly during diagnostic dilemmas. Diffuse MDM2 and p16INK4a immunostaining, together seem useful for triaging cases for FISH.

OFP-24-002

Dermatofibrosarcoma protuberans: ten years’ experience of a Portuguese tertiary institution

D. Gigliano*, A. Coutada, J. Vaz Silva, J. Azevedo, J. Vieira, M. Afonso

*IPO-PORTO, Portugal

Background & objectives: Dermatofibrosarcoma protuberans (DFSP) is a mesenchymal neoplasm, characterised by locally aggressive growth, frequent recurrences, and extremely rare metastases. We aimed to assess the clinicopathologic features of all DFSPs diagnosed at our hospital in the last 10 years.

Methods: A retrospective search of our database yielded a total of 68 DFSPs, diagnosed at our institution from 2011 to 2020. All cases were reviewed clinicopathologically (including age, size and site of tumour, morphology, surgical margins status, number of local recurrences and distant metastases) and submitted to FISH analysis.

Results: Median age was 43.5 years (range 1-77) and male-to-female ratio was 1.48:1. There was marked predilection for the trunk (62.7%), with the remainder cases affecting limbs (23.9%) and head and neck (13.4%). Median tumour size was 2.35cm (range 0,7-24). The cohort included cases with classic morphology (54.4%), fibrosarcomatous transformation (29.4%), melanin pigmentation (7.4%), myxoid change (3.0%) and/or myoid nodules (3.0%). Hybrid morphology (DFSP with areas of giant cell fibroblastoma) represented 8.8% of cases. Surgical margins were positive in 40.3%. Local recurrence was seen in 53.0%, with multiple relapses in 13,2%. Distant metastasis occurred in one case of fibrosarcomatous DFSP (1.48%). COL1A1 gene rearrangements were identified in 95.5%.

Conclusion: Being aware of the wide morphological spectrum of DFSP is necessary for a correct diagnosis. In harmony with literature, and probably due to the difficulty of achieving negative margins, recurrence rates were remarkably high in our cohort, while distant metastases were exceptional. COL1A1 gene rearrangements were present in the vast majority of cases. FISH analysis provided valuable information for the diagnosis in challenging cases.

OFP-24-003

Clinicopathological features of dermatofibrossarcoma protuberans treated with Imatinib

E. Dvindenko*, F. Santos

*Instituto Português de Oncologia de Lisboa Francisco Gentil, Portugal

Background & objectives: Dermatofibrosarcoma protuberans (DFSP) is a fibroblastic neoplasm carrying a COL1A1-PDGFB fusion and often presenting with multiple recurrences. Although surgery remains the standard treatment, the recent introduction of Imatinib as a treatment option has shown significant activity against locally advanced DFSP.

Methods: We retrospectively assessed five cases of DFSP diagnosed and treated with Imatinib in our institution from 2010 to 2020. We reviewed the medical records regarding demographics, clinical and radiologic features of the tumour, treatment course and clinical response. Histological findings from pre and post-Imatinib treatment surgical and biopsy specimens were reviewed and morphological treatment response was recorded.

Results: All patients were male. Median age was 50 years (range 27-53). All underwent treatment with Imatinib 400mg. Clinical reduction in tumour size was seen in all cases. Fibrossarcomatous DFSP was diagnosed in 3 patients, with COL1A1-PDGFB fusion detected in 2. One of these cases showed significant response with hipocellularity, hyalinization, fibrosis, necrosis, chronic inflammation and hemosiderin deposition. Two fibrossarcomatous cases had poor responses. The two remaining cases of conventional DFSP showed partial response with areas of hypocellularity, hyalinization and fibrosis, with focal residual tumour. Four patients are alive and disease-free after a median of 46.4-months follow-up and one patient died with metastatic disease

Conclusion: DFSP often presents with unresectable tumours. Some cases benefit from adjuvant treatment with Imatinib, showing clinical responses and allowing surgical resection with wider margins. Scarce data is available regarding histological features of treated DFSP. Most cases show areas of hypocellularity, myxoid stroma, fibrosis, hyalinization and necrosis, with variable foci of viable tumour. Larger series of treated DFSP are needed in order to validate an adequate and standardized evaluation system of histological treatment response.

OFP-24-004

Angiosarcoma of the breast: a single institution experience

A. Coutada*, S. Carvalho, D. Gigliano, J. Vaz Silva, J. Azevedo, R. Isidoro, B. Ferreira, A. Ferreira, S. Conde, C. Leal, M. Afonso

*Pathology Department of the Portuguese Oncology Institute of Porto, Portugal

Background & objectives: Breast angiosarcoma is a rare tumour. It may occur de novo, as a complication of prior radiotherapy for breast cancer or in association with chronic lymphedema (Stewart-Treves syndrome). Herein we describe a single institution experience over the past 20 years.

Methods: Retrospective analysis of all cases diagnosed at Portuguese Oncology Institute of Porto between 2000-2020. Evaluation of clinicopathologic features, including age at diagnosis of breast cancer and angiosarcoma, interval between radiotherapy and diagnosis of angiosarcoma, treatment rendered for each neoplasm and time from diagnosis of angiosarcoma to death. Tumour size and grade, number of local recurrences and metastasis were also assessed.

Results: Twenty cases were identified: 4 primary angiosarcoma (PAS) and 16 secondary angiosarcoma (SAS), 2 associated with Stewart-Treves syndrome. Median age (41 years vs 70 years) was lower in PAS and median tumour size (5.85cm vs 4.3cm) was higher. The vast majority of tumours (n= 17) were high grade. Median time from radiation to SAS diagnosis was 6.3 years. Total mastectomy was the main surgical treatment. Follow-up (median, 18.5 months) revealed that 4 patients (3 SAS) recurred locally, 6 patients (4 SAS) had distant metastasis, and 11 patients (9 SAS) died of disease, on average, 20 months after diagnosis. Median overall survival: 29 months for PAS and 18 months for SAS.

Conclusion: Breast angiosarcoma is an aggressive tumour with poor long-term prognosis. Primary tumours occur in younger patients. Secondary tumours are more frequent and the incidence of radiation-associated angiosarcomas seems to be increasing. The results of our series are similar to those described in the literature.

OFP-25 | Uropathology

OFP-25-001

An international validation study of automated cancer detection in prostate biopsies

Y. Tolkach*, V. Ovtcharov, A. Pryalukhin, W. Hulla, M. Eich, P. Caie, E. Runde, R. Büttner

*University Hospital Cologne, Germany

Background & objectives: Digital pathology provides an opportunity for computational analysis of histological slides and the standardized automation of some pathological tasks. In this retrospective study, we validate a deep learning-based tool for prostate cancer detection from patient biopsy samples.

Methods: A prostate cancer detection tool was developed and implemented in HALO AI® and HALO AP® software (Indica Labs, Albuquerque, US). Two external validation cohorts of patients with multifocal prostate biopsy were analysed: Cohort 1/Dataset 1 (n full cases = 65) digitized by Hamamatsu S360, Cohort 2 (n = 57) digitized by Hamamatsu S360 (Dataset 2) and Leica GT450 (Dataset 3).

Results: Similar high accuracy metrics were received for all three datasets implying good generalization among cases from different institutes and digitized by different scanner systems. For Dataset 1, Dataset 2, and Dataset 3, respectively: the negative predictive value was 0.99, 0.98, and 0.97; sensitivity was 0.97, 0.94, and 0.91; specificity was 0.93, 0.94, and 0.96; overall accuracy was 0.941, 0.942, and 0.946. Domain adaptation strategies for institution and scanner system improve the final accuracies. Several cores were detected where tumour was missed by pathologists (Cohort 1: n=7, Cohort 2: n=5). The average analysis time was 1 minute / core in Cohort 1, and 2 minutes / core for Cohort 2.

Conclusion: The prostate cancer detection tool reported high accuracy for prostate cancer detection in biopsy cases during external validation; independent of the institute or scanner used. It is fully integrated into Indica Labs’ digital pathology platform and can assist pathologists in the form of pre-screening or quality control during analysis of prostate biopsy cases.

OFP-25-002

Large cribriform growth pattern does not have additional prognostic value above small cribriform architecture on prostate cancer biopsies

L. Rijstenberg*, T. Hansum, C. Kweldam, S. Remmers, M. Roobol-Bouts, A. Van Leenders

*Department of Pathology, Erasmus MC, Rotterdam, The Netherlands

Background & objectives: Invasive cribriform and intraductal carcinoma (IDC) are associated with adverse features in prostate cancer patients, with large cribriform fields having the worst outcome in prostatectomies. Our objective was to determine the impact of large cribriform pattern in prostate cancer biopsies.

Methods: A prostate biopsy cohort (n=1887) with long-term clinical follow-up was reviewed for Grade Group according to the 2014 ISUP guidelines. Presence of small and large cribriform pattern were monitored, with large cribriform pattern having at least twice the size of adjacent benign glands. Hazard ratios (HR) for metastasis-free survival and prostate cancer-specific mortality were calculated using Cox proportional hazards regression.

Results: Cribriform growth was found in 280/1887 men: 1.1% in Grade Group 1, 18.2% in Grade Group 2, 57.1% in Grade Group 3, 55.4% in Grade Group 4 and 59.3% in Grade Group 5. Large cribriform growth was found in 47/1887 men: 0.5% in Grade Group 2, 9.8% in Grade Group 3, 18.1% in Grade Group 4 and 17.3% in Grade Group 5. Presence of cribriform growth showed significantly worse metastasis-free survival (small cribriform/IDC: HR 3.04; large cribriform: HR 3.17) and prostate cancer-specific mortality (small cribriform/IDC: HR 4.07; large cribriform: HR 4.13). Large cribriform fields did not have additional adverse prognostic value for metastasis-free survival (P=0.77) or prostate cancer-specific mortality (P=0.96).

Conclusion: We demonstrate that both invasive cribriform and intraductal carcinoma are associated with worse metastasis-free and disease specific-free survival in a large prostate biopsy cohort. In contrast to radical prostatectomies, the presence of large cribriform fields does not have additional adverse prognostic value in prostate biopsies. This discordance could be explained by cribriform pattern sampling artifacts and limitations of size estimation on biopsies. Any cribriform growth pattern should therefore be reported in prostate cancer biopsies without size limitations.

OFP-25-003

Epigenetics in renal cell tumours – expression patterns of histone H2AX

M. Zivotic*, D. Dundjerovic, J. Filipovic, G. Nikolic, D. Petrovic, M. Tubic, K. Ilic, S. Radojevic Skodric

*Institute of Pathology, Faculty of Medicine, University of Belgrade, Serbia

Background & objectives: Epigenetic effects have been widely recognized in Renal Cell Tumours (RCT), thus we investigated the expression of H2AX histone in RCT and its correlation with demographic, clinical and pathohistological characteristics regarding immunohistochemical positivity.

Methods: The analysis included a total of 168 RCT (102 clear cell Renal Cell Carcinomas (RCC), 7 papillary type I RCC, 15 papillary type II RCC, 23 chromophobe RCC, 5 multilocular-cistic RCC, 6 collecting duct carcinoma, 10 oncocytomas) and was performed on tissue microarray slides using H2AX (1:1000, clon ab11175, Abcam) histone.

Results: Expression of H2AX in RCT was variable: in some tumours it was not detected, while other tumours expressed it in diffuse or focal patterns. Diffuse patterns were observed among patients with significantly lower mean age (48.1 ± 25.2 years) compared to those with focal (58.6 ± 16.2 years) and absent (59.7 ± 14.5 years) patterns, p=0.003. Moreover, diffuse H2AX expression pattern was frequently associated with high immunostaining intensity, while focal form mostly exhibited low H2AX intensity level, p<0.001.

Conclusion: H2AX is decreased with aging, suggesting an involvement of the current epigenetic mechanism in RCT development without specific influence on tumour morphology and biological behaviour.

Funding: Ministry of Education, Science and Technological Development of the Republic of Serbia (project No. OI 175047)

OFP-25-004

Novel double staining (OCT4/CD34) for the detection of lymphovascular invasion in OCT4(+) Germ Cell Tumours: technical aspects, results and future prospective

C. Ricci*, M. Borsato, T. Franceschini, F. Giunchi, M. Fiorentino

*Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Italy

Background & objectives: Lymphovascular invasion (LVI) is prognostically relevant in germ cell tumours (GCT) but studies showed discrepant results and low agreement with H&E. We tested double staining (DS) for OCT4/CD34 in GCT, providing the methodological aspects, the results and its potential implications.

Methods: We retrospectively analysed 25 GCT [15 OCT4(+) and 10 OCT4(-)] diagnosed between January 2019-February 2021 at our Institution. DS was performed on FFPE, 3-μm-thick sections (BenchMark ULTRA), with OCT4 stain visualized with DAB and CD34 one with FastRed. The slides (H&E and DS) were assessed by two uropathologists (M.F., C.R.) to assess the LVI with the two different techniques.

Results: Of the 15 OCT4(+) GCT tested, 15 (100%) stained with OCT4 at DS. Conversely, 0/10 (100%) of the OCT4(-) GCT showed any nuclear stain at DS. The normal parenchyma [OCT4(-)] and GCNIS [OCT4(+)] served as internal controls. According to its nature of “pan-lymphovascular” marker, C34 stained both lymphatic and vascular structures. In all cases, DS showed results superimposable to the single ones (OCT4 and CD34), with no discrepancies of nuclear and cytoplasmatic stains. In the groups of OCT4(+) GCT, LVI was detected in 5/15 (33.3%) and 7/15 (46.7%) cases with H&E and DS, respectively; as results, one of the latter two changed its pT stage (1b to 2).

Conclusion: In conclusion, DS for OCT4/CD34 showed to be technically reliable and potentially suitable for the evaluation of LVI in a significant subgroup of GCT. Future studies on larger case series and with long-term follow-up are needed to validate its prognostic implications (increase in the number of cases positive for LVI and so pT2 at TNM staging, with crucial therapeutic implications) and its effects on inter- and intra-observer agreement in the LVI assessment of GCT.

OFP-25-005

Vessels encapsulating tumour clusters (VETC) in renal cell carcinoma (RCC). prognostic role and predictive value to tyrosine kinase inhibitors (TKI) therapy. A Bayesian retrospective clinico-pathological study

S. Renne*, M. Valeri, M. Perrino, L. Di Tommaso, L. Terracciano, P. Colombo, P.A. Zucali

*Humanitas University, Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, Rozzano, Italy

Background & objectives: VETC is a new metastatic mechanism in HCC where it is prognostic and predictive of sorafenib response. VETC is also present in RCC. We aim to investigate its prognostic and to model its predictive to TKI response in RCC.

Methods: To evaluate the overall survival (OS) effect, we included 92 primary RCC from 2005 to 2007 (Surgical-Series) and all RCC patients treated with first line TKIs at our center (TKI-series; Sunitinib, n=39; Pazopanib n=17), and recorded the progression free survival (PFS). VETC was assessed with CD34 immunohistochemistry and defined as a continuous endothelial lining around tumour clusters.

Results: VETC+ cases had a worse prognosis in the Surgical-Series, with a posterior probability density (PPD) of median OS of 88 months (mo) (standard deviation, SD:16mo) for VETC+ Vs 136mo (SD:26mo) for VETC-; the expected loss of median OS was 48mo (SD:31mo) for VETC+RCC. Conversely in the TKI-Series, VETC+ showed longer PFS: Sunitinib had a PPD of median PFS of 35mo (SD:11mo) for VETC+ Vs 19mo (SD:5mo) for VETC-. Under Pazopanib a PPD of median PFS of 20mo (SD:8mo) for VETC+ Vs 11mo (SD:7mo) for VETC-. The expected gain of median PFS for of VETC+RCC, was 17mo and 9mo (SD: 12mo and 9mo), respectively for Sunitinib and Pazopanib.

Conclusion: Our results confirmed the general adverse prognostic role of VETC in RCC, however this phenotype gave a substantial PFS gain for patients treated with TKI, similarly to what have been observed in HCC. VETC could be a new predictive bio-marker that allows the delivery of a personalized treatment: patients affected by RCC might directly benefit from a better selection of already approved drugs.

OFP-25-006

PD-L1 expression and tumour-infiltrating lymphocytes: combined use as urothelial carcinoma biomarkers

F. Ramalhosa*, M. Garcia, M.B. Pimentão, P. Teixeira, R. Almeida, M.J. Martins, V. Sousa

*Pathology Department, Hospitais da Universidade de Coimbra, Centro Hospitalar e Universitário Coimbra, Portugal

Background & objectives: Programmed death ligand-1 (PD-L1) has been associated with an increased survival rate and can be evaluated by immunohistochemistry (IHC). The main goal is to correlate the expression of PD-L1 with tumour Infiltrating Lymphocytes (TILs) (CD8 expression) in urothelial carcinoma (UC).

Methods: Forty-three samples of high grade UC diagnosed in 2019 and 2020 were selected from archive of the Pathological Anatomy Service (SAP) of Centro Hospitalar Universitário de Coimbra(CHUC) and tissue microarray (TMA) were constructed. PD-L1 immunostaining was performed with different clones (SP142, SP263 and 22C3). The information collected were organized in a database and subjected to statistical analysis using the SPSS.

Results: TILs are greater in female patients, when using 20 lymphocytes / High Power Field (HPF) cutoff (median expression). TILs positive cases are lower in basal IHC subtype carcinomas (p=0.045, p<0.05) when considering the cutoff of 50 lymphocytes / HPF and have a tendency to be higher in histologic grade 2 tumours (p=0.0814). Positive correlations between PD-L1 22C3 with CD8 expression (cutoff 50) (p=0.024, p<0.05) and PD-L1 SP263 with CD8 (cutoff 50) (p=0.002, p<0.05) were found.

Conclusion: Higher TILs (CD8 expression) levels are correlated with higher PD-L1 expression, highlighting their use as biomarkers.

OFP-25-007

Digital pathology reporting of TRUS biopsies of prostate

T. Pasupati Meenakshi*

*Clinipath Sdn Bhd, Malaysia

Background & objectives: Digital pathology is an integrated component of primary reporting in Clinipath Pathology, Malaysia for the past two years. Due to the Covid 19 pandemic outbreak in 2020, most of the TRUS biopsies were reported digitally, away from the office.

Methods: An advanced Aperio AT2 slide scanner (Leica ), which has been approved by FDA , is in usage for digital pathology reporting in Clinipath. A total number of 119 TRUS biopsy cases, many of which had a minimum of 12 cores and also targeted biopsies with MRI mapping for precision and accuracy were reported, individually, as per latest International guidelines.

Results: Digital pathology reporting of TRUS biopsies is as accurate as conventional microscope reporting, and in many instances, more advantageous. With an integrated Dragon Speech software, all cases were reported with ease, without resorting to the conventional microscope for a review. The response and acceptance from the urologists have been over whelming.

Measurements of percentage of small malignant foci, and interpretation of Gleason pattern, coupled with digital photography has made the system more rewarding. Constant and perpetual practice has made the digital reporting more dependable, robust, and accurate than conventional microscope reporting. IHC analysis with comparison of various IHC markers in a single view is a prolific outcome of digital reporting.

Conclusion: Digital pathology reporting OF TRUS biopsies of prostate is simple, dependable, accurate and should be incorporated as a regular primary reporting procedure, where digital pathology is available. The accuracy and effectiveness are very advantageous for the current demand of uropathology in many laboratories. This will become the norm of future diagnostic digital pathology and artificial intelligence(AI).

OFP-25-008

Incidental prostatic adenocarcinoma in cystoprostatectomy specimens for bladder cancer: a 21-year institutional case review

T. Oliveira*, M. Pinho, D. López-Presa

*Department of Pathology, Hospital de Santa Maria, CHULN, Portugal

Background & objectives: Radical cystoprostatectomy is recommended as a treatment modality in high-risk non-invasive bladder cancer and in muscle-invasive bladder cancer. Herein, we aimed to review all cystoprostatectomy specimens received by our institution in a 21-year period (2000-2020) for incidental prostatic neoplasia.

Methods: We reviewed the reports of 232 cystoprostatectomy specimens for urothelial cancer and evaluated the prostate for the following parameters: presence of prostatic adenocarcinoma, Gleason score, prostatic intraepithelial neoplasia (PIN), prostate volume and percentage occupied by tumour, number of tumour foci, laterality, invasion of extra-prostatic tissues or seminal vesicles, positive surgical margins, staging, PSA levels before surgery, relapse and metastases.

Results: In total, there were 67 patients (28.9%) with incidental prostatic acinar adenocarcinoma, with a mean age of 70 years and an average total PSA level of 2.2 ng/ml. There were 50 cases (74.6%) graded Gleason 6 and 17 cases (25.4%) graded Gleason 7. Prostatic intraepithelial neoplasia (PIN) was highly associated with prostatic adenocarcinoma (85.7%) while being present in only a minority of specimens without it (21.6%). The tumours occupied, on average, 12.6% of the prostatic volume, were mostly multifocal (53.7%), bilateral (59.7%) and stage pT2 (94.0%), with only 4 cases (6.0%) being pT3. Only one patient showed biochemical relapse (PSA: 146 ng/ml) and cervical bone metastases.

Conclusion: In our series, the incidental prostatic carcinomas were all acinar adenocarcinomas, mostly small, bilateral, Gleason 6 and stage pT2. These results are similar to the findings reported for radical cystoprostatectomy specimens and autopsy series. The detection of these tumours on cystoprostatectomy specimens is not an uncommon finding and is to be expected in older patients. Although follow-up is warranted, the concomitant urothelial carcinoma and its complications remain the major risk factors to the patients’ overall survival.

OFP-25-009

ACO2 expression as a common characteristic of primary and metastatic renal cell carcinoma

A. Kowalewski*, D. Jaworski, P. Antosik, J. Durślewicz, M. Smolińska, D. Grzanka, Ł. Szylberg

*Department of Clinical Pathomorphology, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Poland; Department of Tumour Pathology and Pathomorphology, Oncology Centre-Prof. Franciszek Łukaszczyk Memorial Hospital, Bydgoszcz, Poland

Background & objectives: Renal cell carcinoma (RCC) continues to pose a great challenge due to our limited understanding of its underlying pathophysiology. We explored relationships between ACO2 protein expression and the clinical courses of RCC using the tissue microarray (TMA).

Methods: The TMA contained 94 cores of primary tumour, matched metastases and matched adjacent tissues derived from 31 RCC patients. The mean follow-up was 84.1 months. Tumour samples were evaluated for ACO2 expression using the H-score, and its correlations with clinicopathological data and survival data were analysed.

Results: All of the tissue samples showed ACO2 cytoplasmic expression, with the median value of 139.7, 130.3 and 166.7 in primary tumour, metastatic tissue and control group, respectively. Normal adjacent tissues were characterized by significantly higher ACO2 expression comparing to primary or metastatic RCC (p<0.05). The analysis demonstrated a significant positive correlation between ACO2 expressions in primary tumour and its metastases (p<0.05). The correlation between two variables was strong (r = 0.7301). The expression of ACO2 did not significantly correlate with overall survival, tumour size or incidence of capsular or vain invasion (p>0.05).

Conclusion: Significant alterations in ACO2 expression presumably occur in the early stages of RCC carcinogenesis. Taking into account the physiological role of ACO2, its downregulation may constitute an adaptive trait of RCC to escape the equilibrium phase of immunoediting.

Funding: This research was funded by The National Centre for Research and Development, grant number POWR.03.02.00-00-I019/16.

OFP-25-010

PTEN loss And PD-L1 expression among morphology patterns of Gleason grade 4 prostate cancer

G. Kir*, G.E. Cecikoglu, A. Yildirim

*Istanbul Medeniyet University, Turkey

Background & objectives: The Gleason grading system is clearly accepted for the evaluation of prostate cancer architectural patterns. We aimed to find out whether PTEN immunohistochemical loss of expression and PD-L1 expression is associated with specific histological patterns.

Methods: The current study included consecutive 98 radical prostatectomy specimens between 2011 and 2017. We selected 151 foci with different patterns from 98 radical prostatectomies. PTEN and PD-L1 immunohistochemistry were assessed on the different architectural patterns.

Results: There were foci with grade 3 pattern in 18 slides, foci with fused gland pattern in 39 slides, foci with cribriform pattern in 28 slides, foci with irregular gland pattern in 47 slides, foci with glomeruloid pattern in 4 slides, and foci with grade 5 pattern in 15 slides. Fifty foci (%33.3) exhibited PTEN loss. PTEN loss was substantially associated with cribriform pattern (<0.001 ). Combined PDL-1 score was positive in 13% of patients (1 foci with grade 3 pattern, 3 foci with fused gland pattern, 1 foci with cribriform pattern, 7 foci with irregular gland pattern, 1 foci with glomeruloid pattern, and 3 foci with grade 5 pattern).

Conclusion: Between the five different grades, Gleason grade 4 is certainly a heterogeneous group, containing different architectural patterns. Lately, the cribriform pattern has attracted more attention as an independent negative risk factor. The results of our study showed that PTEN loss was significantly associated with cribriform patterns. We observed that PD-L1 was most commonly seen in foci with irregular gland pattern(44%) There was no statistically significant difference between six histological patterns regarding PD-L1 positivity.

OFP-25-011

Should we report the distance to the anterior margin for PSA recurrence prediction?

E. Kara*, Ö. Başaran Aydogdu, S. Senel, M.S. Ali Al-Jefri, C. Özden, S. Tastemur, B. Gök, A. Yazgan, B. Gumuskaya

*Ankara Şehir Hastanesi, Turkey

Background & objectives: Since anterior aspect of prostate tissue is irregular, measuring distance to anterior margin is controversial. Our aim is to investigate the relation between PSA recurrence and distance to the anterior margin in anterior dominant Grade Group 1(GG1) prostate cancers.

Methods: A number of 20 GG1 radical prostatectomy specimens (RPs) with anterior dominant tumour were included in this study from 836 RPs from 2010 to 2016. PSA recurrence was defined as PSA level of greater than or equal to 0.2 ng/mL. Slides were re-viewed in order to select the closest margin. Scanned slides were marked by pathologists to acquire digital measurements.

Results: Tumours of 9/20 cases were closer than 1 mm to the margin. Among these 9 cases 3(33.3%) of them had PSA recurrence. The distance from tumour to margin was greater than 1 mm in 11 cases. Out of these 11 cases one (9.09%) had PSA recurrence. The mean and median follow-up for PSA recurrences of the cases was 6.8 and 6.5 years (range, 5-11 years). The PSA recurrence was found in 4(20%) cases. And 3 out for 4 had margin closer than 1 mm. The mean distance of recurrent 4 cases was 1.15 mm (median 0.7;range, 0.26-2.93) compared to 1.64 mm (median 1.085; range, 0.05-4.29) for cases without PSA recurrence.

Conclusion: Although there are few numbers of anterior-dominant tumour cases, the surgical margin distance at the anterior aspect of prostate may have an impact on prognosis of such cases. The long-term follow-up of the patients with GG1 P-Ca may reveal that the tumour distance to the anterior margin can be an important prognostic feature, which should take place in the radical prostatectomy reports in the future.

OFP-25-012

Solitary fibrous tumour (SFT) of kidney and renal hilus: 15 cases with special emphasis onSTAT6 and PAX8 expression

G. Güner*, M. Michal, A. Yazgan, N. Onak Kandemir, B. Gümüşkaya Öcal, J. Lopez, O. Hes, P. Argani, K. Kösemehmetoğlu

*Hacettepe University Med. Fac., Turkey

Background & objectives: SFT is a fibroblastic tumour characterized by a haphazard proliferation of spindled to oval cells, staghorn hemangiopericytoma (HPC)-like vasculature and STAT6 expression. Although already published in case reports or small series, a comprehensive series of primary renal SFT is lacking.

Methods: Fifteen primary kidney SFTs were reviewed for clinical, morphological, and immunohistochemical features. STAT6 (BioSB, EP325, 1/250 and Santa Cruz, D-1, 1:800), CD34 (Leica, QBEND-10, 1/100) , BCL-2 (Invitrogen, BCL-2-100, 1/600) and PAX8 (CellMarque, MRQ-50, 1/150 and Proteintech, 10336-1-AP, 1:800) immunostainings were performed.

Results: Mean age was 50,3(17-83) with equal sex distribution. Mean size was 9,3(2,5-23) cm. Tumours were mainly well-demarcated and located at the hilus. Morphologically, they were grouped as 1) SFT-like (5 cases) characterized by hypocellularity and abundant collagen; 2) HPC-like(6 cases) showing hypercellular proliferation of small-ovoid cells lacking collagen; 3) mixed SFT/HPC(4 cases). 40% had myxoid degeneration and/or accompanying lymphocytes. All cases were positive for CD34, BCL-2, and STAT6(focal, 27%). PAX8 was positive in 27%. According to Demicco-grading, 12 cases(80%) were low-risk (all cases of groups 1-2), while 2(13%) and 1(7%) were intermediate- and high-risk, respectively. One high-risk patient died while 7 were alive for an average follow-up period of 57 months.

Conclusion: Renal SFTs can exhibit SFT-like, HPC-like or mixed morphology. Most cases (especially SFT-like and mixed HPC/SFT) are benign but occasional malignant examples occur and it seems that current SFT classification schemes effectively predict such behaviour in this anatomical location as well. PAX8 positivity and only focal STAT6 expression in a subset of cases is an important diagnostic pitfall.

OFP-25-013

Significant inter- and intra-laboratory variation in Gleason grading of prostate cancer: a nationwide study of 35,258 patients in The Netherlands

R. Flach*, P. Willemse, B. Suelmann, I. Deckers, T. Jonges, C. van Dooijeweert, P. van Diest, R. Meijer

*Department of Oncological Urology, University Medical Centre Utrecht, The Netherlands

Background & objectives: Gleason grading (GG) of prostate cancer (PCa) is essential for patient treatment and prognosis. Studies showed inter-observer variation in GG. As GG variation between pathology laboratories has not been investigated, we analysed inter- and intra-laboratory grading variation using nationwide data.

Methods: Needle biopsy reports (n=42,774) and corresponding prostate specific antigen (PSA)-values were retrieved for January 2017–December 2019 from the Dutch Pathology registry and The Netherlands Cancer Registration.

We determined laboratory-specific proportions per histologic grade and unadjusted odds ratios (OR) for International Society of Urological Pathologists (ISUP) Grades 1 versus 2-5. Logistic regression was performed to correct for case-mix variables.

Results: 38,321 Reports of 35,258 patients were included, of which 25,367 were narrative reports and 12,954 standardized, synoptic reports. Laboratories assigned ISUP Grade 1 to 34.1% of patients on average, ranging from 19.7-44.3%. Laboratory-specific ORs were significantly deviated for 22/40 laboratories, ranging from 0.48 (95% confidence interval (CI) 0.39-0.59) to 1.54 (CI 1.22-1.93). Case-mix correction was performed for 10,294 synoptic reports of 21 laboratories for variables PSA, age, diagnosis year, number of biopsies and positive cores. Case-mix correction altered the status of three laboratories. The range of adjusted laboratory-specific proportions increased compared to unadjusted proportions (20.8% vs. 17.7%). Within 15/21 (71.4%) laboratories that consented to intra-laboratory analysis, significant inter-pathologist variation existed.

Conclusion: Substantial variation in PCa grading was observed between and within Dutch pathology laboratories. Case-mix correction changed the status of individual laboratories but did not change the magnitude of the observed variation. Grade is an essential for treatment strategy and patient prognosis. The observed variation suggests that patients might receive different grading and subsequently different treatment depending on laboratory and pathologist. Better standardization of PCa grading is warranted to optimize and harmonize treatment.

Funding: This research was funded by the Quality Foundation of the Dutch Association of Medical Specialists (SKMS) and Astellas BV

OFP-25-014

Unexpected low metastatic potential to lymph-nodes of isolated tumour cell and cluster-cord in ISUP 5 prostate adenocarcinoma (PC): morphological analysis of a mono-institutional cohort of radical prostatectomy (RP) with lymph-node metastasis (LNM)

M. Cieri, V. Belsito, M. Valeri, G. Elefante, C. De Carlo, G. Lughezzani, N.M. Buffi, L. Terracciano, P. Colombo*

*Department of Pathology, IRCCS Humanitas Research Hospital, Humanitas University, Rozzano Milan, Italy

Background & objectives: Gleason pattern 5 (GP5) includes distinct morphologies, namely undifferentiated solid pattern (US), cribriform with necrosis (CN), cluster and cord (CC), and isolated single tumour cells (ISTC). We histologically characterized these different subtypes in LNM comparing them with the primary tumour.

Methods: ISUP 5 were collected from a mono-institutional cohort of 2784 pts between 2014 and 2020, from which 79 PC with LNM cases were identified. The different subtypes of GP, tumour volume, topographical distribution, intraductal component, pT, margin status, and vascular invasion were determined both in LNM and primary tumour.

Results: In LNM, GP5 was documented in 22/79 cases, either alone or in combination with other patterns. US, CN, ISTC and CC were documented in 13 (16.4%), 8 (10%), 5 (6.3%), and 4 (5%) cases, respectively. Primary PC harboured ISTC in 35/79 cases, but the same pattern was rare in the associated LNM (3/35), only as minor component (alone in one case, with CC in one, with US in one). ISTC did not show differences in lymph-node topographical distribution (parenchymal, capsular, extra-capsular) compared with other patterns. Overall, 53/79 (67%) LNM were dominated by GP4, mostly represented by cribriform pattern. The presence of ISTC/CC did not correlate with pathological parameters analysed.

Conclusion: Our results showed that ISTC and CC patterns, although not uncommon in the primary tumour, are unfrequently observed in the loco-regional lymph-nodes. Although in limited cases, these preliminary data could suggest that ISTC and CC use a different spreading way to disseminate when compared with cribriform pattern. This low intrinsic capability to spread into loco-regional lymph nodes could be modulated on a genomic level, and further studies are ongoing to better understand the biology of these subtypes of GP5.

OFP-25-015

The switching phenotype and intratumor plasticity in urothelial bladder carcinoma (UC): a mono-institutional analysis of 211 muscle-invasive tumours with considerations for therapy

C. De Carlo, M. Cieri, P.A. Zucali, G. Elefante, N. Rudini, F. D'Antonio, R. Hurle, M. Lazzeri, L. Giordano, M. Perrino, G. Guazzoni, L. Terracciano, P. Colombo*

*Department of Pathology, IRCCS Humanitas Research Hospital, Humanitas University, Rozzano Milan, Italy

Background & objectives: UC classification into Basal and Luminal categories has shown variable sensitivity to chemotherapy. We conducted a phenotypical analysis of UC cases from transurethral resection specimens to evaluate the intra-tumour plasticity (switch) between the superficial and deep component of the tumour.

Methods: High grade UC cases were analysed using a simple immunohistochemical score (Piescore) focusing on the expression of CD44, CK5/6, CK20 and pPARg in superficial (pTa/T1) and muscle-invasive (pT2) component of tumour to identify Luminal, Basal, Mixed, Null (Neu-like) categories. To increase the specificity of the analysis, 20 cases were also investigated with RT-PCR.

Results: Two hundred-eleven cases were collected. Superficial component showed Luminal, Basal, Mixed and Neu-like phenotype in 99 (46.1%), 61 (28.9%), 33 (15,6%) and 18 (8.5%) cases, respectively. RT-PCR analysis confirmed immunohistochemical results. From superficial to deep component, a switch of phenotype was observed in 80/211 (38%) cases, from Luminal (42/80, 52.5%) to Neu-like (20), Basal (16), and Mixed phenotype (6); from Mixed (29/80, 36.2%) to Basal (21), Luminal (3), and Neu-like phenotype (5). Among 18 Neu-like, 4 (22.2%) acquired new phenotypes, while only 6/61 Basal tumours switched. Papillary tumours switched more frequently than not-papillary (52/112, 46.4% vs 26/99, 26.3%) (p=0.0385). Phenotypical transition did not correlate to OS and PFS.

Conclusion: Piescore system revealed phenotypic plasticity through the evaluation of a switch between superficial and deep component of the same tumour. The switch is frequent in Luminal but not in Basal tumours. After cystectomy, a protective effect of CD44 expression in OS (p=0.0016) and in PFS (p=0.0042) was observed. This variability could partially explain the sensitivity of a subset of Luminal UC to chemotherapy: good responders could be "non-real" Luminal UCs, which acquire Basal markers such as CD44.

OFP-25-016

Immunohistochemical and molecular comparative characterization of ipsilateral synchronous papillary renal cell neoplasm with reverse polarity and clear cell renal cell carcinoma

D. Bueno Sacristán*, T. Caniego Casas, A. Ferrer Gómez, E. Moreno Moreno, M.R. Meléndez Gispert, F.J. Burgos Revilla, J. Palacios, C. Varona Crespo, A. Saiz González

*Ramón y Cajal University Hospital, Spain

Background & objectives: Ipsilateral synchronous renal clear cell renal cell carcinoma (CCRCC) and papillary renal cell neoplasm with reverse polarity (PRCNRP) is an exceptional finding in renal pathology. PRCNRP, characterized by a hallmark mutation in KRAS, displays unique morphology and immunoprofile.

Methods: We present an extremely rare case of coexisting PRCNRP and CCRCC in the same kidney on a 77-year-old patient with no oncologic medical history. Morphological and immunohistochemical features of both tumours are described. Molecular analysis using an in-house next generation sequencing (NGS) panel was performed in samples of normal renal parenchyma and both neoplasms.

Results: Histologically, CCRCC showed a classic morphological and cytological features and so did PRCNRP. The latter displayed a pure papillary architecture with hyalinized fibrovascular cores. Papillae were lined by a single layer of non-stratified tumour cells with large, eosinophilic cytoplasm and apically located nuclei. Immunohistochemical studies showed positive staining for MUC1 and GATA3. Negative staining for a-methylacyl-coenzyme A racemase (AMARC) and vimentin was described. NGS results evidenced mutations in CDH19, COL1A1 and EGFR in both tumours and normal kidney. CCRCC also showed a mutation in TAF1 gene. PRCNRP demonstrated the hallmark mutation in KRAS.

Conclusion: To the best of our knowledge, this is the second reported case of collided CCRCC and PRCNRP. Immunohistochemical and molecular studies evidenced not only characteristic features of both tumour but confirmed the diverse oncogenic origin of each entity. PRCNRP has arisen as a new and underdiagnosed entity in renal pathology, with distinctive molecular and pathologic findings. Early follow-up studies have suggested better data in terms of recurrence and metastasis in comparison with other papillary neoplasms.

OFP-25-017

Power to the pathologist - immunofluorescence or chromogenic antibody-guided annotations improved the analytical performance of the algorithm compared to manual annotated whole H&E slide images in prostate cancer core-needle biopsies

L. Björk*, F. Hikmet, J. Svensson, F. Fraggetta, W. Rezner, M. Seliga, P. Bobkiewicz, A.(L. Makkus, A. Bychov, J. Fukuoka, K. Eurén, S. Elfwing, C. Lindskog

*Dept. Department of Women's and Children's Health, Karolinska Institutet/Digital Pathology, ContextVision, Sweden

Background & objectives: To better the concordance and objectivity in the evaluation of prostate core-needle biopsies, we developed an AI-based decision-support tool and algorithm to specifically detect and outline neoplastic glandular tissue using an in-house high-resolution staining and annotation method - Master Annotation.

Methods: To reduce the turnaround time and improve the objectivity of our training data, we developed a patented multiplex-staining method to train our algorithms to detect and outline suspicious glandular tissue without basal cells and intraductal cancer.

Pathologists annotated, in high-resolution mode, of H&E whole-slide images, assisted by re-stained and aligned immunofluorescence or consecutive chromogenic IHC whole slide images.

Results: The semantic segmentation algorithm, in INIFY® Prostate (ContextVision, Sweden) was trained within a deep learning framework developed in-house at ContextVision.

The algorithm was evaluated on 58 prostate slides, stained at five different laboratories and scanned on three different WSI-scanners. It achieved a median pixel-level sensitivity and specificity of 98.4% and 97.5%, respectively, on cancer images, and a specificity of 99.0% on benign images, using a tolerance of 3 pixels (or approximately 21 μm).

Conclusion: Master Annotation enabled a micron-level region of interest and an augmented segmentation ground truth for our input-data of the deep learning algorithm.

Using this approach, we have developed INIFY® Prostate, a CE marked AI-based software that a clinical setting, predicts, outlines, and quantifies suspected cancer areas in prostate biopsy H&E stained whole slide images.

Funding: The work was in part funded by Verification for collaboration, Uppsala University and the European Regional Development Fund

OFP-25-018

First results of a retrospective observational performance study of INIFY® prostate screening in the clinical pathology workflow: FIRST-PATH

M. Tranchina, P. Amico, L. Björk*, D. Johansson, L. Kajland Wilén, F. Fraggetta

*Dept. Department of Women's and Children's Health, Karolinska Institutet/Digital Pathology, ContextVision, Sweden

Background & objectives: Prostate cancer is the second most frequent cancer for men in Europe but grading suffers from discordance and low objectivity in the histopathologic evaluation.

FIRST PATH study aims to evaluate performance and usability of INIFY-Prostate in the clinical pathology workflow.

Methods: The feasibility phase of the FIRST PATH study included 100 WSI's (59 benign, 41 cancer) from 12 retrospective anonymised cases. Two study pathologists diagnosed all WSI's without INIFY, and then after wash-out-period with the support of INIFY. A panel of 3 senior pathologists did the final consensus diagnosis. All diagnoses in the study were blinded (inter- and intra-pathologists).

Results: The diagnostic accuracy as well as diagnostic concordance of pathologists with INIFY was higher than the corresponding values without INIFY. The two study pathologists judged INIFY’s performance as good/acceptable for 12 of 12, and 11 of 12 cases, respectively. In comparison to the reference diagnosis, seven (7) whole slide images (WSIs) that were incorrectly diagnosed without INIFY, but were then correctly diagnosed with INIFY, while only one (1) correct diagnosis without INIFY rendered incorrect with INIFY.

The % tissue area of cancer given by the INIFY algorithm correlated well with the pathologists’ estimates of % cancer length within the respective cores (Spearman rank correlation 0.80, p<0.001).

Conclusion: Preliminary results indicate that INIFY Prostate Screening performs well and gives good support to pathologists in the clinical workflow. The observed improvements of diagnostic accuracy and concordance between pathologists need to be confirmed in the full FIRST PATH clinical study.

OFP-MD-01 | Molecular Pathology Diagnostics Symposium Orals

OFP-MD-01-001

Detection of on-target ALK inhibitor resistance mutations and treatment options for patients with non-small cell lung cancer

B. Koopman, H. Groen, E. Schuuring, W. Timens, L. van Kempen*, A.J. van der Wekken, on behalf of the UMCG Molecular Tumor Board

*Department of Medical Biology, University Medical Centre Groningen, The Netherlands

Background & objectives: Non-small cell lung cancer (NSCLC) patients with Anaplastic Lymphoma Kinase (ALK) gene fusions respond well to ALK inhibitors but commonly develop on-target resistance mutations. The objective of this study is to collect clinical evidence for subsequent treatment with ALK inhibitors.

Methods: Local experience with on-target ALK resistance mutations and review of the literature identified 387 patients with ALK inhibitor resistance mutations and subsequent treatment results. Clinical benefit of mutation-inhibitor combinations was assessed based on reported response, progression-free survival and duration of treatment. Furthermore, this clinical evidence was compared to previously reported in vitro sensitivity of mutations to the inhibitors.

Results: Of the 387 patients included in this analysis, 239 received a different ALK inhibitor after developing on-target resistance to first line ALK inhibitor therapy. Clinical benefit was reported for 177 (68%) patients but differed for each mutation-inhibitor combination. Agreement between in vitro predicted sensitivity of six published models and observed clinical benefit ranged from 64 to 87%. The observed clinical evidence for highest probability of response in the context of specific on-target ALK inhibitor resistance mutations is presented.

Conclusion: Molecular diagnostics performed on tissue samples that are refractive to ALK inhibitor therapy can reveal new options for targeted therapy. The comprehensive overview of clinical evidence of drug actionability of ALK on-target resistance mechanisms may serve as a practical guide to select the most optimal drug for individual patients.

OFP-MD-01-002

NTRK gene fusions in MLH1 deficient and BRAFV600E wild-type colorectal cancers

I. Ukkola*, P. Nummela, M. Kero, S. Kytölä, P. Peltomäki, A. Ristimäki

*HUS - Helsinki University Hospital, Finland

Background & objectives: NTRK fusions are oncogenic drivers and offer targets for cancer therapy. Since they are rare in colorectal cancer (CRC), universal screening for these fusions in CRC seems impractical. Our aim was to investigate NTRK fusions in a subset of CRC.

Methods: Pan-Trk (clone EPR17341, Roche, Ventana) immunohistochemistry (IHC) and MLH1 promotor hypermethylation (MLH1ph) were analysed in 63 CRC cases with deficient MLH1 (dMLH1) and BRAFV600E wild-type (wt) status from CRCs resected at the Helsinki University Hospital in 2018-2020. Pan-Trk immunopositive cases were evaluated by targeted RNA-based NGS (Fusion Plex Comprehensive Thyroid and Lung Kit, ArcherDX Inc.).

Results: Of the 63 dMLH1/BRAFV600Ewt CRCs seven (11.1%) cases were Pan-Trk IHC positive and each of them was confirmed to harbor NTRK1 fusion by NGS. Detected fusions involved LMNA-NTRK1, TPM3-NTRK1 and PLEKHA6-NTRK1 each in two cases and IRF2BP2-NTRK1 in one. MLH1ph status was determined using methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) with SALSA MS-MLPA Probemix ME011-D1 Mismatch Repair Genes kit (MRC Holland) comprising 44 dMLH1/MLH1ph/BRAFV600Ewt CRCs. All NTRK1 fusions were in the subgroup of MLH1ph (7/44; 15.9%). Pan-Trk immunostaining pattern showed strong or moderate cytoplasmic staining in TPM3-NTRK1 and IRF2BP2-NTRK1 cases, stronger membranous than cytoplasmic staining in PLEKHA6-NTRK1 cases, and the only cases showing perinuclear staining were the fusions for LMNA-NTRK1.

Conclusion: Our study shows that Pan-Trk IHC detects NTRK1 fusions with 100% specificity in CRC. Our results confirm that NTRK1 fusions are frequently detected in dMLH1/BRAFV600Ewt (11%) and especially in dMLH1/MLH1ph/BRAFV600Ewt (16%) CRCs justifying screening for NTRK fusions in these subsets of CRCs. Our findings of NTRK1 fusions with partners LMNA, PLEKHA6 and TPM3 in CRC are consistent with previous studies but noteworthy, we introduce a novel IRF2BP2-NTRK1 fusion in CRC.

OFP-MD-01-003

Nationwide evaluation of mutation-tailored treatment of gastrointestinal stromal tumors in daily clinical practice

L. Steeghs*, H. Gelderblom, V.K. Ho, Q.J. Voorham, S. Willems, E. Schuuring, K. Grünberg, M.J. Ligtenberg

*Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands; Department of Pathology, the Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, The Netherlands; Department of Pathology, Leiden University Medical Center, The Netherlands

Background & objectives: Molecular analysis of KIT and PDGFRA is critical for tyrosine kinase inhibitor treatment selection of gastrointestinal stromal tumors (GISTs). We performed a nationwide real-world data study into the application of predictive mutation testing and its impact on treatment decisions.

Methods: Real-world clinical and pathology information was obtained from GIST patients with initial diagnosis in 2017–2018 through database linkage between the Netherlands Cancer Registry and the nationwide Dutch Pathology Registry.

Results: Predictive mutation analysis was performed in 89% of the patients with high risk or metastatic disease. Molecular testing rates were higher for patients treated in expertise centers (96%) compared to non-expertise centers (75%, P<0.01). Imatinib therapy was applied in 81% of the patients with high risk or metastatic disease without patient’s refusal or adverse characteristics, e.g. comorbidities or resistance mutations. Mutation analysis, that was performed in 97% of these imatinib-treated cases, did not guarantee mutation-tailored treatment: 2% of these patients had the PDGFRA p.D842V resistance mutation and 7% initiated imatinib therapy at the normal instead of high dose despite of having a KIT exon 9 mutation.

Conclusion: In conclusion, nationwide real-world data show that over 81% of the eligible high risk or metastatic disease patients with GIST receive targeted therapy, which was tailored to the mutation status as recommended in guidelines in 88% of cases. Therefore, still 27% of these GIST patients misses out on mutation-tailored treatment. The reasons for suboptimal uptake of testing and treatment require further study.

Funding: This work was supported by the research program Personalized Medicine of the Netherlands Organization for Health research and Development (ZonMw, project number 846001001).

Computational Pathology Symposium Orals

CP-03 | Computational Pathology Symposium: Evening Session

CP-03-001

Clinical level AI-based solution for primary diagnosis and reporting of prostate biopsies in routine use: a prospective reader study

E. Comperat*, N. Rioux-Leclercq, O. Levrel, V. Rouleau, J.P. Terrier, F. Neumann, D. Raoux, L. Bien, G. Decktor, S. Rossat, M. Vecsler, D. Laifenfeld, M.B. Amin

*Sorbonne University, France

Background & objectives: This study aimed to clinically validate the use of an AI-based tool by pathologists for reviewing and reporting prostate core needle biopsies (PCNBs) as compared with Standard of Care review on microscope, also assessing improvements in efficiency and turnaround time.

Methods: A two-arm prospective reader study comparing the performance of pathologists using an AI-based solution workflow compared with the use of standard of care (pathologists using a microscope). Both arms were compared to ground truth (GT) established by consensus of two subspecialist uropathologists. Rates of major discrepancies between each arm and GT, as determined by an adjudicating expert uropathologist, were compared.

Results: Eight pathologists participated in the study and reported on 785 H&E slides from 100 PCNB consecutive cases. Each case was reported twice, once in each study arm. The major discrepancy rates of the microscope and of the AI-based solution arms against GT were 7.15% and 4.84%, respectively. The AI solution demonstrated very high performance on prostate cancer detection with AUC=0.99, sensitivity of 95.5%, and specificity of 96.2%. Other endpoints included sensitivity and specificity of both arms on cancer detection and grading. The study demonstrated that reporting with the AI-based solution leads to >30% efficiency gains and a significant decrease in TAT.

Conclusion: This is the first large-scale study, in which pathologists perform full primary diagnosis with the support of an integrated AI-based solution in a real world-like clinical setting, in a large network of pathology laboratories. Importantly, diagnostic accuracy improvements are observed in addition to significant efficiency gains for the pathologists reviewing and reporting with the integrated AI solution.

CP-03-002

Multiple-instance learning for assessing prognosis of ductal carcinoma in situ

F. Dal Canton*, M. van Seijen, E. Groen, H. Horlings, E. Lips, E. Gavves, J. Teuwen, J. Wesseling, G.C. PRECISION Consortium

*Netherlands Cancer Institute, The Netherlands

Background & objectives: We propose a Deep Learning-based pipeline to aid pathologists in the task of distinguishing Ductal Carcinoma in Situ (DCIS) cases with low versus high risk of progression to ipsilateral Invasive Breast Cancer (iIBC), using H&E whole-slide images (WSIs).

Methods: We use a Multiple-Instance Learning-based Deep Learning pipeline to predict 10-year iIBC recurrence of DCIS from H&E stained WSIs. We also explore automatic mammary duct detection as an input selection strategy, and we compare it to standard WSI tiling. The resulting models are trained and evaluated on 414 H&E stained WSIs provided by the Netherlands Cancer Institute.

Results: All classification results are obtained on a validation set which remains untouched until after model training and selection, and which contains good balance between the positive and negative class. When using detected ducts as its input, the proposed pipeline achieves up to 0.71 in area under the Receiver Operating Characteristic curve (precision: 0.68; sensitivity: 0.61; specificity: 0.75). Classification performance increases significantly when we exclude patients treated with adjuvant radiotherapy from both the training and validation sets. In this case the pipeline achieves up to 0.86 in ROC-AUC (precision: 0.89; sensitivity: 0.71; specificity: 0.89).

Conclusion: Our pipeline achieves remarkable classification performance, substantially improving over both human assessment and over the only comparable recent machine learning-based approach. Our results show that a Multiple-Instance Learning pipeline using score average-pooling aggregation is more likely to produce correct classifications for the low-risk group when applying duct detection as an input selection strategy as opposed to dense tiling, showing promise for tackling the problem of over-treatment of DCIS.

Funding: This work was supported by Cancer Research UK and by KWF Kankerbestrijding (ref. C38317/A24043).

CP-03-003

Computer aided assessment of melanocytic lesions by means of a mitosis algorithm

B. Sturm*, D. Creytens, J. Smits, A. Ooms, E. Eijken, E. Kurpershoek, H. Küsters-Vandevelde, C. Wauters, W. Blokx, J. van der Laak

*Pathan B.V., The Netherlands

Background & objectives: An increasing number of pathology laboratories are fully digitised. In this study a mitosis algorithm primarily developed for breast carcinoma is applied to melanocytic lesions. This study aims to study the added value of this algorithm in diagnosing melanocytic lesions.

Methods: A set of 99 digitally scanned melanocytic skin lesions for which a consensus diagnosis was reached was subjected to a mitosis algorithm based on convolutional neural networks. Two academic and six non-academic surgical pathologists specialized in dermatopathology examined the WSI cases, first without and after a washout period of at least 2 months with mitosis annotations based on the algorithm.

Results: The overall concordance of the pathologists with the consensus diagnosis for all cases excluding nevoid melanoma (n=89) appears to be comparable with and without the use of artificial intelligence (AI) (89% vs. 90%). However, the concordance increases by using AI in nevoid melanoma cases (n=10) (75% vs 68%). All but one pathologist reported more dermal mitoses with the mitosis algorithm which on a regular basis were incorrectly attributed to mitoses from mainly leukocytes. In 3 cases the algorithm indicated a correct dermal mitosis in a melanocyte that was not in accordance with the consensus diagnosis.

Conclusion: This study shows that in general cases pathologist perform similarly with the aid of a mitosis algorithm. In nevoid melanoma cases, pathologists perform better with the algorithm. This study shows that pathologists need to be aware of potential pitfalls using CAD, e.g. misinterpreting dermal mitoses in non-melanotic cells.

CP-03-004

Single-cell architecture of the tumour microenvironment predicts response to cancer immunotherapy

C. Schuerch*, D. Phillips, M. Matusiak, B. Rivero Gutierrez, S. Bhate, G. Barlow, S. Jiang, K. Smythe, Y. Goltsev, R. West, M. Khodadoust, Y. Kim, G. Nolan

*University Hospital Tübingen, Germany

Background & objectives: Immunotherapies can induce long-lasting remissions in advanced-stage cancer patients, but many patients do not benefit. We reasoned that characterizing the tumour microenvironment (TME) architecture at the single-cell level should reveal novel spatial biomarkers of immunotherapy response.

Methods: We performed CODEX highly multiplexed tissue imaging to investigate the TME in cutaneous T cell lymphoma (CTCL) patients treated with pembrolizumab anti-PD-1 immunotherapy. 55 protein markers were visualized simultaneously in a tissue microarray of matched pre- and post-treatment skin biopsies from 7 responders and 7 non-responders. RNA sequencing was performed to extract cell-type specific gene expression profiles by CIBERSORTx analysis.

Results: We identified and characterized 21 spatially resolved tumour and reactive immune cell clusters in the CTCL TME. Advanced computational analysis of tumour architecture revealed cellular neighbourhoods that dynamically changed during pembrolizumab therapy and were correlated with response. Furthermore, a spatial signature of cell-cell distances between tumour cells, regulatory T cells (Tregs) and PD-1+CD4+ effector T cells predicted therapy outcome. After treatment, in pembrolizumab responders PD-1+CD4+ effector T cells up-regulated the cytotoxic molecule granzyme B, whereas in non-responders the frequency of ICOS+ Tregs increased. In addition, CIBERSORTx analysis revealed that tumour cells in responders, but not in non-responders, enhanced the expression of immune-activating genes, particularly the T cell chemoattractant CXCL13.

Conclusion: The pre-existing immune status of the CTCL TME is associated with specific immune cell types, cellular neighbourhoods and architectural features that correlate with pembrolizumab response. Multidimensional analysis of the TME enables discovering spatial predictive biomarkers and generating novel mechanistic hypotheses of immunotherapy response, paving the way for future studies functionally addressing these cell types and their interactions.

CP-03-005

Histocartography: an entity-based workflow for histology image analysis

P. Pati*, G. Jaume, A. Foncubierta Rodriguez, M. Gabrani

*IBM Research Zurich, Switzerland

Background & objectives: Cancer diagnoses rely on phenotype and topological distribution of histological entities. However, deep learning techniques for cancer analysis operate at pixel-level which disregards the notion of such entities. We propose Histocartography, a generalized entity-based paradigm to address the aforementioned issue.

Methods: Histocartography begins with tissue pre-processing. Subsequently, we construct entity-graph representation, where nodes and edges depict histological entities and inter-entity interactions in the tissue. The choice of entity type, entity embedding, and topological formulation can be customized using task-specific pathological prior. Afterward, Graph Neural Network (GNN) is employed to map structure-to-function relationship. Finally, post-hoc graph explainability techniques explain the GNN’s decision.

Results: We released Histocartography python package, a collection of image-to-graph translation, state-of-the-art GNNs, and graph explainers to facilitate interpretable entity-based analysis. A REST API prototype with user-friendly interface is deployed to seamlessly onboard pathologists. Currently, Histocartography supports entity-graphs using nuclei, tissue regions, or both as entities for arbitrary image dimensions. We included pre-trained GNNs to map breast tumour regions-of-interest onto 7 breast carcinoma subtypes. We include 4 graph explainers to generate post-hoc explanations, and an explainability module to produce pathologist-friendly quantitative measures. Average processing time for a 1K´1K region-of-interest on an NVIDIA P100 GPU is 2s, 0.01s, 0.3s, and 0.2s for cell-graph generation, GNN inference, explanation generation, and quantitative measurements respectively.

Conclusion: Histocartography lays the foundation for a one-stop solution to access graph-based analysis in computation pathology. It enables developers to build customized graph representations and task-specific GNNs. It provides an interpretable input space in terms of relevant histological entities to pathologists which they can relate to and reason with. Finally, the explainability module generates easy-to-understand localized explanations. Currently, the service only includes solutions for breast carcinoma, and we are in process of extending to other organs, disease types, and pathology tasks.

Posters

PS-01 | Autopsy Pathology Posters

PS-01-001

Adrenal gland developmental anomalies – rare necroptic findings

C. Amalinei*, A. Grigoras, L.A. Riscanu

*"Grigore T. Popa" University of Medicine and Pharmacy Iasi and Institute of Legal Medicine Iasi, Romania

Background & objectives: Adrenal gland is formed of two embryological-distinct layers: the cortex and medulla. Adrenal gland anomalies are relatively rare and most cases are incidental autopsic findings. We present two cases of developmental anomalies of the adrenal gland diagnosed in our Department.

Methods: Necroptic examination has been associated to collection of tissue specimens for microscopy, followed by routine hematoxylin-eosin staining.

Results: The developmental anomalies of the adrenal gland occurred in two subjects, a 69 and a 76-years old men. The histopathological examination revealed a fusion between renal and adrenal cortex in one case and an area of adrenal tissue which was located under the liver capsule in another case. Considering the adrenal gland embryological development, ectopic adrenal tissues are usually found in the vicinity of the adrenal gland or along the trajectory of embryonic migration, within or near the urogenital tract. However, ectopic adrenal in the liver is also a possibility, although extremely rare, as in a case of our report.

Conclusion: Incidental anomalies of adrenal gland are occasional findings in forensic pathology. Adrenal-renal fusion and ectopic adrenal tissue may be incidentally discovered during the necropsy, the microscopic examination being important in certification of diagnosis. The differentials from benign lesions to malignant and potentially lethal conditions are important in the context of tanatogenesis.

PS-01-002

Incidental haemangiomas in forensic pathology

C. Amalinei*, A. Grigoras, L.A. Riscanu, T. Iov, R.A. Balan

*"Grigore T. Popa" University of Medicine and Pharmacy Iasi and Institute of Legal Medicine Iasi, Romania

Background & objectives: Haemangioma is a common benign vascular tumour derived from blood vessel cells. The objective of our study is to report the particular features of incidental haemangiomas necroptically diagnosed, from our files.

Methods: The autopsic reports of our Department, from the last 5 years, have been reviewed, and 47 cases of haemangiomas have been selected. These cases have been investigated by routine paraffin-embedding, followed by hematoxylin-eosin staining.

Results: The cases were diagnosed in 31 males and 16 females, age ranging between 41 weeks gestational age up to 78 years old. Gross findings were that of small, well delimited red-brown masses, of up to 2 cm diameter. The microscopic examination revealed the proliferation of thin-walled blood vessels, lined by a single layer of flat endothelial cells, without atypia, within the liver tissue, in a subcapsular location, in 84.09% of cases, with characteristic features for cavernous haemangioma in 91.48% of cases and of capillary haemangioma in 8.51%. The other cases revealed three rare locations, as following: left atrium cavernous haemangioma, renal corticomedulllary junction capillary haemangioma, and umbilical cord cavernous haemangioma.

Conclusion: Haemangioma is the most common benign liver tumour, but it may develop in any location. Differentials should include other vascular tumours, such as lymphangioma, benign (infantile) haemangioendothelioma, hemangioblastoma, epithelioid haemangioendothelioma, and angiosarcoma. Haemangiomas may be significant in legal medicine when large, compressing vital organs or when spontaneously or traumatically ruptured, if it prevents the foetal development (e.g. umbilical cord location), or if it determines sudden death (e.g. cardiac location).

PS-01-003

Cerebellum metastasis mimicking the dissemination of a malignant pheochromocytoma

C. Amalinei*, A. Grigoras, L.A. Riscanu, D.G. Ciobanu Apostol, L. Lozneanu

*"Grigore T. Popa" University of Medicine and Pharmacy Iasi and Institute of Legal Medicine Iasi, Romania

Background & objectives: Central nervous metastases are relatively frequent in forensics. We present the particular features of a female subject, of 69 years old, which presented multiple tumours, located in adrenal gland, lung, pleura, and cerebellum, associated with lymphadenopathy.

Methods: Necroptic examination has been associated to collection of tissue specimens for microscopy. Routine hematoxylin-eosin staining, along with immunohistochemistry using a panel of markers (Cytokeratin AE1/AE3, CK5, CK7, CK20, p63, TTF-1, Synaptophysin, Chromogranin, Melan A, Calretinin, Inhibin, and S100) have been used in order to discriminate between primaries and secondaries.

Results: The gross findings were that of multiple tumour masses with variable areas of necrosis and adenopathy. The microscopic examination of tumour cells showed variable nuclear atypia, eosinophilic cytoplasm, the differential between a metastatic lung squamous cell carcinoma and a metastatic malignant pheochromocytoma being investigated. The tumour cells expressed diffuse, strong positivity of AE1/AE3 and CK5, focal Melan A positivity, and also focal adrenal CK7 positivity. Negative stains included CK20, p63, TTF-1, Synaptophysin, Chromogranin, Calretinin, Inhibin, and S100. Accordingly, the diagnosis of poorly differentiated lung squamous cell carcinoma with pleural invasion and lymph nodes, adrenal gland, and cerebellum metastases has been certified.

Conclusion: Central nervous system metastases are mainly located in brain hemispheres and spinal cord but, rarely, they may be located in cerebellum, as seen in this case report. Immunohistochemistry is useful to distinguish primary and metastases in cases with multiple disseminations, including adrenal gland, and AE1/AE3 and CK5 association shows a high specificity in metastatic lung squamous cell carcinomas.

PS-01-004

Location variability of incidental hydatid cysts

C. Amalinei*, A. Grigoras, L.A. Riscanu, B.G. Ioan

*"Grigore T. Popa" University of Medicine and Pharmacy Iasi and Institute of Legal Medicine Iasi, Romania

Background & objectives: Hydatid cysts are incidental findings in forensics, involving liver and rarely lung, abdomen cavity, spleen, ovaries, uterus, cervix, fallopian tubes, and broad ligaments. The aim of our study is to report the features of incidental hydatid cysts from our files.

Methods: The reports from autopsies performed in the last 5 years in our Department, have been reviewed, selecting 19 cases of hydatid cysts, with cases age distribution between 37 to 89 years old, 4 females and 15 males. The cases have been investigated by routine paraffin-embedding sections, followed by hematoxylin-eosin and trichrome staining.

Results: The gross findings showed single cysts with maximum diameter of 80mm, low consistency, with subcapsular liver location in 17 cases (89.47%), while another case showed a subcapsular splenic location. In one case, multiple cystic structures, of up to 30mm diameter, with partially calcified wall, forming a tumour-like mass have been detected within the anterior right ribs 1-3. The microscopic exam revealed laminated membrane, inflammatory infiltrate rich in lymphocytes and eosinophils, pericystic fibrosis, necrosis, and dystrophic calcifications. The endocyst with the inner germinal layer and partially lithic scolices have been detected in 63.15% of cases. Differential diagnoses included inflammatory cysts, neoplastic diseases, and trauma-related lesions.

Conclusion: Incidental hydatid cysts or echinococcosis are relatively rare in forensic pathology, usually being located in liver. These appear as single or multiple cysts, associated with variable inflammation, fibrosis, and calcification. However asymptomatic echinococcosis progression may result in unexpected findings and locations and, as a consequence, this diagnosis should be considered in endemic areas. The differentials, from benign lesions to malignant and potentially lethal conditions, are important in the context of causes of death.

PS-01-005

COVID-19 and autopsy, a case series

M.M. Buda*, C. Miguel, Z. Estivariz, È. Iglesias, N. Santiago, N. Barriobero, A. Martinez, Á. Pérez Rodríguez, A. Bugallo, A. Aguilera, I. Guerra

*Clinical Department Unit of Pathological Anatomy, OSI Araba, Araba University Hospital, Bioaraba Health Research Institute, Vitoria-Gasteiz, Alava, Spain

Background & objectives: The novel coronavirus has caused million of deaths since the start of the global pandemic. In this situation, the pathological examination is more important than ever to understand the pathophysiology of this new disease.

Methods: 31 autopsies of patients who died with COVID-19 infection were performed between May 2020 and February 2021. There were performed 27 thoracic and 4 thoracoabdominal autopsies. All of them were carried out in BSL-3 rooms. Patients had an age range between 44 and 89 years old, 28 of them were male and 3 were female.

Results: Lungs had a congestive appearance and were heavy. Microscopically the most consistent finding in all cases was the presence of diffuse alveolar damage. It was seen in an exudative phase with the presence of hyaline membranes, in a proliferative phase with reactive type II pneumocytes and even in a fibrotic phase. Eight patients showed acute organizing and fibrinous pneumonia and sixteen patients showed thrombotic phenomena. Microbiological cultures were performed and 28 patients had viral, bacterial and fungal superinfections what lead to pneumonia and lung abscesses. The lung parenchyma also showed the presence of multinucleated giant cells in ten cases. Emphysema, squamous metaplasia and lambertosis were seen in 16 patients.

Conclusion: This study reveals the importance of the autospy in understanding the changes produced in the body by the SARS-CoV-2. The lungs were the most affected organ with the presence of acute and chronic processes. Also, as mentioned, many patients showed thrombotic phenomena with lung thromboembolism. These findings are consisten with the fact that the new coronavirus affects the vasculature exerting a prothrombotic effect. All in all, further investigation are necessary in order to shed light on this pandemic.

PS-01-006

Histopathological clues in a case of ethylene glycol ingestion

D. Costache*, A.M. Vrâncianu, A. Simionescu, A. Tița, M. Bosa, L. Luca

*Pathology Department, Colentina University Clinical Hospital, Bucharest, Romania

Background & objectives: Ingested ethylene glycol(EG) is metabolised into four organic acids: glycolaldehyde, glycolic acid, glyoxylic acid and oxalic acid(OA), causing severe acidosis, central nervous system depression, cardiopulmonary and renal failure. OA precipitates as calcium oxalate monohydrate(COM) in the kidneys and other tissues.

Methods: We present a case of fatal EG poisoning of a 44-year-old male found dead in his home. An autopsy was performed and samples of brain, lung, heart, liver, spleen, stomach, kidney and adrenal were taken. The organs were fixed in formalin, processed, embedded in paraffin and examined on H&E. Blood, urine and gastric content samples were sent for toxicological examination.

Results: Microscopic examination revealed that the kidneys were the most affected showing moderate chronic pyelonephritis, nephroangiosclerosis, areas of acute tubular necrosis with extensive intratubular deposition of translucent, colourless, refractile crystals of COM, with multi-coloured birefringence under the polarized light.

Other findings were: cerebral cortex stasis, perineuronal and perivascular oedema; meninges with arachnoid fibrosis, meningothelial hyperplasia and psammoma bodies; atherosclerosis of the coronary artery branches, hypoxic changes in cardiomyocytes, with moderate perivascular and interstitial fibrosis and lipodystrophy; massive stasis and alveolar oedema in the lungs with few vascular fibrin thrombi; a small cavernous hepatic haemangioma and an adrenal cortical adenoma of 2 cm diameter.

Toxicological tests revealed lethal levels of EG.

Conclusion: EG can be found in many agents, such as antifreeze. Ingestion of EG, accidental or in suicide attempts, causes poisoning which can be fatal.

COM accumulates in the kidney by attachment of crystals to tubular cell membranes, followed by endocytosis, resulting in structural damage of cell membranes, production of free radicals and lipid peroxidation, malfunction in the mitochondria of proximal tubule cells and consequently, renal tubular necrosis. Microscopic findings together with the toxicologic report are diagnostic for EG poisoning.

PS-01-007

Determination of survival time following isolated head trauma by histopathological method

D. Dagva*, B. Khasbagana, T. Minjuur, B. Enkhbat

*Department of Pathology and Forensic Medicine, School of Biomedicine, Mongolian National University of Medical Sciences, Ulaanbaatar, Mongolia; Department of Forensic Medicine, National Institute of Forensic Science, Ulaanbaatar, Mongolia

Background & objectives: The objectives of this study were determine the demographic characteristics of patients who died from isolated head injuries having no surgery and to determine their survival time based on histopathological changes in the injury hematoma and brain.

Methods: Between 2018 and 2019 the Department of Forensic Medicine of the National Institute Forensic Science recorded 3895 deaths of which 810 cases had head trauma. A subset of 398 of these patients with isolated head trauma were analysed. The tissues from 50 of these patients underwent histopathological analysis to determine the time from injury to death.

Results: Out of 398 cases studied, 326 (82%) were male, 72 (18%), were female (male to female ratio 4.5:1) and most (n=119, 30%) were within 40-49 years of age (mean age 42±13.2). Trauma to the anterior head was the most common location of injury (259, 65%). We identified 50 cases to estimate time from injury to death by histological examination using Martius Scarlet Blue stain. Among these cases 15 died between 0-6 hours after head trauma, 3 died between 6-12 hours, 22 cases died between 12-18 hours, 3 cases died between 18-24 hours, 2 case died 24-48 hours, and 5 cases died 48 hours after head injury.

Conclusion: Males who suffered death from traumatic head injuries from blunt objects were most frequently identified in our research. Brain oedema, subarachnoid haemorrhage, frontal skull fracture and brain contusion were most common. The interval of time from the head trauma to death was determined by the age of the fibrin using histochemistry stain.

PS-01-008

Haematolymphoid malignancies in clinical autopsy - our institution experience

C. Dahlstedt-Ferreira*, S. Carralas Antunes, R. S. S. Oliveira, M.J. Brito

*Hospital Garcia de Orta, EPE, Portugal

Background & objectives: In the past decades, autopsy rates have declined for a multitude of reasons. Despite technological diagnostic advances, the number of malignancies missed during clinical evaluation has not declined. Hereby, we focused on haematolymphoid malignancies (HLM) due the challenges they present.

Methods: The present study was an observational record-based study, with consult of autopsy reports and patient’s medical files. We evaluated all the autopsies performed at our institution over the last 12 years (2009-2020), with the purpose of characterizing HLM in autopsy context. All the data was analysed as frequency and proportion.

Results: During this research, we found that, since 2009, 366 autopsies were performed at our institution. Of those, 98 were associated with neoplasms: 80 epithelial malignancies and 18 HLM. Regarding HLM, 6 were female and 12 were male with a mean age of 69 years old. 2 had been previously diagnosed [Non-Hodgkin Lymphoma (NHL) and Plasma cell neoplasms (PCN)], 5 were under study for occult malignancy [(4 NHL and 1 Myeloproliferative/myelodysplastic neoplasm/syndrome (MM/NS)] and the remaining 11 were not diagnosed/suspected clinically (8 NHL, 2 PCN and 1 MM/NS).

Conclusion: HLM usually course with nonspecific clinical manifestations being most of the time diagnostically challenging. Generally, they have a poor clinical outcome and prompt treatment may be lifesaving. With the present study we try to emphasize the persisting relevance of the traditional postmortem examination, by shedding some light not only in current pathology practice but also by contributing to the improvement of the diagnostic approach in HLM.

PS-01-009

The analysis of mortality among patients with SARS-CoV-2 infection in concomitance with malignant neoplasms

G. Sychugov, E. Kazachkov, D. Gogoleva*, A. Sychugov

*South Ural State Medical University, Russia

Background & objectives: The aim of study was to determine the mortality structure in the autopsy cases of concomitant SARS-CoV-2 infection and malignant neoplasms.

Methods: We assessed 4695 autopsies. In all cases there was post-mortem histological examination and the data of reverse transcriptase-polymerase chain reaction (RT-PCR). The SARS-CoV-2 was determined by RT-PCR in 95% of cases. In 5% of cases there was just typical for COVID-19 clinical and morphological findings without RT-PCR determination.

Results: The overall number of autopsies with SARS-CoV-2 infection and malignant neoplasms was 94/4695 (2%). The median age was 66 years (LQ-58,25; HQ-77,5). The coexisting SARS-CoV-2 infection and hemoblastosis was observed in 46% cases (ICD-10 С91 – 18%; С92-93 – 12%; C90 – 9%; С81-85 – 7%), colorectal cancer in 12% cases (С18-С20), lung cancer in 10% (С34), CNS malignancy in 5% cases (C70-72). The others malignancies were observed in less than 5% of cases.

Pneumonia (31% cases), pulmonary embolism (25% cases), cancer metastasis (13% cases) and shock (13% cases) occurred as a complication.

Conclusion: The most common concomitance of SARS-CoV-2 infection and hemoblastosis was revealed among all types of malignancies. It may be connected with the immune dysfunction associated with hemoblastosis.

PS-01-012

The importance of death verification services in Ceara, a state in the Northeast of Brazil

D. Nunes Oliveira*, L. Goiana Albuquerque, L. Silveira de Oliveira, M.C. Rocha Muniz, P. Natiele Maurício Alves, M. Macêdo Militão Medonça, J. Carneiro Melo, D. Nunes de Melo

*University of Fortaleza, Brazil

Background & objectives: Death verification services (DVS) supply important epidemiological data to improve the healthcare system. In Ceará, it has an important role in decreasing the index for death by ill-defined causes. This study aims to understand the importance of this institution’s implementation.

Methods: The present study consists of a literature review. The articles studied were retrieved from the Scielo database. The descriptors Death, Verification, Services and Importance were applied, utilizing the boolean operator and. Government databases like DATASUS, official government websites and literary works on the subject were also considered. The period from 1996 to 2020 was the search limit.

Results: The DVS in Ceará was created in 2005. It works by identifying the natural causes of death, providing data to the health system and improving its coverage area throughout the state in 2014 with the Mobile Death Verification Service. According to the government's mortality information system, in the nine years prior to the service's implementation, the rate of ill-defined causes of death was 10% above the national target. After the institution's first year of operation, the index dropped to 6.2%. During the dengue outbreaks between 2011 and 2012, 214 post-mortem examinations were performed of which 121 were confirmed as dengue and 42.05% of those had no clinical suspicion.

Conclusion: The death verification service of Ceara has played a fundamental role in collecting data on the diverse types of natural deaths, helping to trace an epidemiological profile that contributes to the improvement of public healthcare in the state.

PS-01-013

Primary amoebic meningoencephalitis (PAM) in North-eastern Brazil: an autopsy report

M. de Lima Pinto*, M. Camelo Ferreira, G. Gerson, G. Holanda Maia, D.I. Magno Cavalcante, R. Faustino de Araújo Neto, G. Leal de Carvalho, A. Lobo Ramos, J. Paulo Salviano Diniz e Souza

*Federal University of Ceará, Brazil

Background & objectives: We report autopsy findings of primary amoebic meningoencephalitis (PAM), caused by Naegleria fowleri, a rare reported disease in Brazil with high mortality, associated with bathing on still hot water.

Methods: Clinical, imaging, and autopsy recordings were reviewed. The patient was a 19-year-old, male college student, immunocompetent, who presented with progressive headache for three days, evolving with aphasia and motor deficit, after bathing on a lagoon during an expedition to the state of Piauí, Brazil. MRI showed multifocal lesions with T2 hyperintensity, intralesional haemorrhage, and heterogeneous pattern of enhancement.

Results: The patient was transferred to the ICU after presenting progressive clinical worsening with intracranial hypertension. After three days, brain biopsy was performed showing necrotizing encephalitis without any identified microorganism. Despite corticosteroid, antifungal and antibiotic therapy, the patient rapidly progressed to death. Autopsy gross findings were: purulent leptomeningeal exudate with haemorrhage along the cerebral hemispheres, brain stem, cerebellum and upper spinal cord, congestion of meningeal vessels, brain oedema with herniation of the uncus and cerebellum. Cerebral hemispheres and cerebellum exhibited multiple necrotic and lytic lesions. A diagnosis of primary amoebic meningoencephalitis caused by Naegleria fowleri was based on epidemiological and histopathological findings of multiple amoeba trophozoites without cystic forms.

Conclusion: Primary amoebic meningoencephalitis is associated with swimming in warm and fresh water where the free-living and thermophilic amoeba Naegleria fowleri may enter the central nervous system through the olfactory nerve epithelium. This is a rare case reported in Brazil that shows the importance of considering PAM in the differential diagnosis of necrotizing lesions of the central nervous system.

PS-01-014

Gastrointestinal tract damage in fatal cases of COVID-19

O. Reshetnikova*, A. Ermakov, L. Rudiuk, S. Morozov, G. Gryzonova

*Immanuel Kant Baltic Federal University, Russia

Background & objectives: The COVID-19 infection now is spreading globally, threatening public health worldwide. Patients with COVID-19 experience acute respiratory syndrome accompanied by several extrapulmonary symptoms. The aim of present study was to reveal digestive system pathology in fatal cases of the COVID-19.

Methods: A full pathological post-mortem examinations were performed in 47 fatal cases of the COVID-19. Medical records and clinical data were studied. Gross pathology of the lungs, digestive system, other internal organs and brain were examined. Tissue samples were taken for histological study. Microscopy of H&E stained slides performed at x10, x20, x40. Gastrointestinal tract pathology features were recorded and analysed.

Results: Our study has shown the features of pulmonary pathology in majority of cases, including interstitial pneumonia, diffuse alveolar damage and hyaline membranes formation. Gastrointestinal tract pathology was found in 21% of cases (nine men and one woman). Foci of dystrophy and necrosis, covered with fibrin films with an admixture of neutrophils and mononuclear cell revealed in stomach and intestines. The glands of the stomach were overflowing with mucous secretion, mucostasis was noticeable in the goblet cells. In addition, lymphocytes, monocytes, leukocytes infiltrations were common findings in oesophageal mucosa, stomach, intestines lamina propria. These changes were accompanied with interstitial oedema, acute plethora of blood vessels, stasis of erythrocytes.

Conclusion: COVID-19 infection responsible for the significant growth of patient’s morbidity and mortality worldwide. Post-mortem examination is an essential tool in understanding pathogenesis and pathomorphology of severe acute respiratory syndrome coronavirus 2. Although the infection primarily affects the respiratory system, it is also a multi-organ pathology, including gastrointestinal pathology. The virus associated cells and tissue injuries along with presence of hemodynamic disturbances, inflammatory reactions significantly contributed to death. Further studies of the relationship between gastrointestinal tract disorders and COVID-19 are considered necessary.

PS-01-015

Disseminated trichinosis - case report of an uncommon parasitosis

M. Varela dos Santos*, J. Santos, C. Pontinha, M. Oliveira

*Central Lisbon University Hospital Centre, Portugal

Background & objectives: Trichinosis is an often unrecognized parasitosis and public health hazard, transmitted by ingestion of the nematode Trichinella. Although it is uncommon in well-developed countries, it is still present in Europe in the XXIst century.

Methods: A 56-year-old Nepalese man presented to the emergency department with a 1-month history of generalized myalgia, fatigue and diarrhoea: his last visit to Nepal occurred 7 months prior to the onset of symptoms. He presented with fever and a rash in his left thigh, and laboratory studies showed a white-cell count of 17,000/μL with 10.1% eosinophils.

Results: The patient was admitted to the Intensive Care Unit with severe sepsis and submitted to lower extremity fasciotomy - after 7 days of treatment with antibiotics and supportive therapy, to which he did not respond favourably, muscle biopsies were performed (left quadriceps femoris): histopathological analysis showed muscle tissue with countless encapsulated cysts of Trichinella species.

15 days after presentation the patient died and an autopsy was performed: samples of various skeletal muscles were obtained, which showed muscle tissue with encapsulated cysts of Trichinella species on the left quadriceps, pectoral muscles, intercostal muscles, diaphragm and temporal muscles. A diagnosis of disseminated trichinosis was made.

Conclusion: Trichinosis is a parasitic disease transmitted by ingestion of viable Trichinella larvae in undercooked meat, with pork and wild boar meat being the primary sources of infection worldwide. Symptoms are nonspecific, which hinders the diagnosis, and severity depends on the amount of larvae consumed and conditions of the host. Histopathological analysis of skeletal muscle samples may, along with serologic testing, confirm the diagnosis.

PS-01-016

The importance of specialist autopsy service in identification of cause of failure and adjustment of structure of novel mechanical assist device

K. Wassilew*

*Denmark

Background & objectives: After years spent on development of an optimised mechanical assist device, few fatal outcomes associated with malfunctioning of this novel device were reported. The aetiology of the device malfunction remained unidentified at the early stage of the product launch.

Methods: After product launch of Heartmate 3, end-stage left ventricular heart failure of an elderly patient was initially successfully treated with mechanical unloading of the left ventricle by this novel device. But soon after surgical implantation, the clinical condition of the patient deteriorated, with a fatal outcome. With consent of the patients' relatives an autopsy was performed by a cardiovascular pathologist.

Results: A to date of necropsy not photodocumented twisting of the inner membrane of the pumps‘ outflow graft was detected, which likely would have remained undetected by trainee pathologists. The finding was met with scepticism by cardiologists and surgeons, as well as by industry, and was suggested to represent an autopsy artefact.

Conclusion: This case highlights the importance of specialist autopsy service, proper (photo-)documentation and open interdisciplinary communication in a highly specialised university hospital setting, together with the importance to keep updated on novel clinical developments, in order to diagnose and communicate postmortem findings confidently, even if they appear alogical or unlikely, and proves the role of pathology in preventing further fatal outcomes caused by design flaws of novel devices in the follow-up phase of the product launch.

PS-02 | Breast Pathology Posters

PS-02-001

Immunohistochemical expression of vascular endothelial growth factor (VEGF-A) in triple negative breast carcinoma and its correlation with clinical and pathological factors

G.I. Baltatescu*, M. Aschie, A.A. Nicolau, M. Enciu, G.C. Cozaru, O. Cojocaru, M. Cristian, A. Mitroi, M. Deacu

*Clinical Service of Pathology, “Sf. Apostol Andrei” Emergency County Hospital, Constanţa, Romania / Center for Research and Development of the Morphological and Genetic Studies of Malignant Pathology, “Ovidius” University of Constanţa, Romania

Background & objectives: Triple-negative breast carcinoma (TNBC) is a BC subtype with no “tailored” therapy. Our objective is to evaluate immunohistochemical expression of VEGF-A and to correlate it with other prognostic factors, in order to establish its potential role as a predictive/prognostic biomarker.

Methods: The present study is a retrospective research encompassing 35 cases of TNBC selected from our hospital, during 1995-2020. Clinical and morpho-pathological data were extracted from electronic records. All cases were retrospectively reviewed and selected samples were submitted for immunohistochemical analysis using VEGF-A; P53; Ki67 biomarkers. The SPPS23.0 software for Windows was used to run the statistical analysis

Results: The mean age of cases included in our research was 64 years-old and the overexpression of VEGF-A was noticed in 65.7% of cases. The most important clinic-morphological features which have been correlated with this pattern of expression were lymph node status, angiolymphatic invasion and TNM stage (p ˂ 0.001). The vast majority of TNBC had a high proliferation rate (82.85%) and it was established a perfect association with overexpression of VEGF-A (p˂0.001). Immunohistochemical evaluation of p53 mutational status revealed that 37.14% presented a mutated immunostaining pattern, most of them with “over-expression” p53 type (69.23%). The mutational pattern of p53 was also correlated with overexpression of VEGF-A (p=0.010).

Conclusion: The need to discover new therapeutic targets for TNBC is imperative because chemotherapy alone is not sufficient to significantly improve the survival of these patients. An additional therapy based on VEGF inhibitors may have an important clinical response, improving the quality of life for these patients. VEGF-A biomarker can be used as a prognostic and predictive biomarker, but further studies and clinical trials are required.

Funding: This work was supported by University “Ovidius” Constanta, Romania (grant-number 5/14.11.2018). This research was performed in the CEDMOG center of the “Ovidius” University of Constanţa.

PS-02-002

Mammary tuberculosis masquerading as a primary breast tumour

S. Barbu*, A.C. Lisievici, T. Georgescu, F. Pop

*Carol Davila University of Medicine and Pharmacy Bucharest, Romania

Background & objectives: Although over one billion people suffer from tuberculosis worldwide, mammary tuberculosis is an uncommon disease even in countries where the incidence of pulmonary and extrapulmonary tuberculosis is high, accounting for less than 1% of breast conditions.

Methods: We report the case of a 49-year-old female patient presenting with a solitary, palpable, ill-defined, firm lump situated in the central quadrant of the right breast and measuring approximately 2 cm. Imaging examination reported a BI-RADS 4c lesion and the patient was referred to the surgery department where she underwent right breast lumpectomy.

Results: Histopathological examination revealed multiple epithelioid cell granulomas composed of Langhans cells, caseous necrosis and lymphocytes, scattered throughout fibroadipose tissue. There was no evidence of microcalcifications, epithelial hyperplasia or malignancy. The pattern of distribution, presence of necrosis and lack of suppurative inflammation excluded a granulomatous lobular mastitis. Immunohistochemical stains confirmed the presence of epithelioid cells (CD68 positive) accompanied by a polyclonal lymphocyte population (CD3 and CD20 positive). Since anti-MPT64 was not available, Ziehl-Neelsen stain was performed, which revealed several acid-fast bacilli. Based on our findings, the patient underwent subsequent CT scans, which revealed patchy pulmonary consolidation as well as poorly defined linear and nodular opacities, consistent with a post-primary pulmonary tuberculosis.

Conclusion: Extrapulmonary tuberculosis occurring in the breast is very rare and it is an uncommon disease even in countries where the incidence of pulmonary and extrapulmonary tuberculosis is high. The first case of breast tuberculosis was reported in 1829 by Sir Astley Cooper. The disease occurs far more frequently in women, especially in their reproductive period. Clinical and imaging data may mimic a malignant neoplasm, but primary breast tuberculosis should be taken into consideration in patients from endemic areas.

PS-02-003

Neuroendocrine neoplasms of the breast: study of 12 cases

A. Bchir*, N. Abdessayed, Y. Fejji, T. Zahmoul, M. Mokni

*Department of Pathology, Farhat Hached Hospital, Tunisia

Background & objectives: Neuroendocrine neoplasms are a rare subtype of breast cancers. It includes all tumours with predominant neuroendocrine differentiation. These neoplasms are classified into neuroendocrine tumour and neuroendocrine carcinoma. The aim of our study is to discuss the clinico-pathological characteristics.

Methods: This is a retrospective study of 12 cases. Data was collected from files of pathology Department of Farhat Hached University Hospital over a period of 2001 and 2020.

Results: The mean age was 66.47 years with extremities ranged between 43 and 89 years. The mean size was 3.76 cm (1- 8.4 cm). Nodule was the most common symptom. Tumours were bifocal in 4 cases. 2 cases had mucinous differentiation and 10 cases were pure neuroendocrine carcinomas. 8 cases were neuroendocrine tumours and 4 cases were neuroendocrine carcinoma. All tumours were positives for synaptophysin and chromogranin A. 6 tumours were classified as stage I, 4 were stage II, one was stage III and one was stage IV. There were 7 cases of luminal A type, 4 cases of luminal B type and 1 case of basal type.

Conclusion: Neuroendocrine neoplasms of the breast affect postmenopausal women in the sixth to seventh decade of life. Clinical presentation is similar to NOS. The diagnosis of neuroendocrine differentiation requires expression of the neuroendocrine markers synaptophysin or chromograninA. The main differential diagnosis is a metastatic neuroendocrine tumour from a non-mammary site. Neuroendocrine tumours are low grade tumours with an outcome similar to NOS. Neuroendocrine carcinomas are high grade tumours. Its morphology and prognostic is similar to small cell carcinoma of the lung.

PS-02-004

Desmoid-type fibromatosis of the breast: A report of 7 cases

N. Ben Abdeljelil*, C. Chabaane, A. Bellalah, B. Lahbacha, S. Mabrouk, M. Njima, R. Hadhri, A. Zakhama

*Department of Pathology, CHU Fattouma Bourguiba Monastir, Tunisia

Background & objectives: Mammary fibromatosisis a rare and locally aggressive benign tumour; it originates from fibroblasts / myofibroblasts within the breast parenchyma and does not metastasize.

Through this study we tried to improve and add to the knowledge of this disease.

Methods: This study included 7 women with desmoid-type fibromatosis of the breast collected over a period of 5 years (2016- 2020) in the department of pathology of the university hospital of Monastir.

Results: Patient’s ages ranged from 26 to 46 years. Breast imaging examinations suggested an invasive breast tumour, likely carcinoma, infiltrating the muscles of the chest wall. An ultrasound-guided core needle biopsy revealed a low-grade myofibroblastic proliferation consistent with breast fibromatosis in two cases. Other patients did not have needle biopsies and underwent surgery. They underwent tumourectomies, with a partial resection of the underlying musculature. Macroscopically, tumours were firm and white measuring between 2 and 9 cm. A definitive diagnosis of breast fibromatosis was established from serial paraffin sectioning and immunohistochemistry using β-catenin. In three cases surgical margins were positive and one among these cases showed a relapse after 12 months.

Conclusion: Desmoid-like fibromatosis is a rare breast neoplasm. Despite its classification as an intermediate soft-tissue tumour, breast fibromatosis does possess the potential for aggressive local behaviour. Breast imaging examinations are not specific for fibromatosis and often imitate breast cancer. Surgery remains a valid option, however, preservation of function and quality of life are essential. The role of adjuvant therapy is also not entirely clear, and the optimal regimes, doses and durations of systemic treatment of the disease require elucidation.

PS-02-005

Male breast carcinomas – a 20-year long series in a tertiary Portuguese hospital

J. Boavida*, R. Moiteiro da Cruz, L. Correia

*Department of Pathology, Hospital de Santa Maria, CHULN, Portugal

Background & objectives: Male Breast Carcinomas (MBC) account for <1% of all cancers in men, largely characterized based on data from female counterparts. This study aims to review several cases of MBC from 2000-2020 registered in our department and contribute to their portrayal.

Methods: Through the National Oncologic Registry, we compiled every case of MBC registered in our hospital between 2000 and 2020, and 45 out of 87 cases were selected to our study; only cases with a pathology report from our department were chosen. Both biopsies and surgical specimens were considered and all available clinicopathological features were summarized and analysed, accordingly.

Results: Median age of diagnosis was 66,1 years (range 36-86 years), occurring equally on both sides, mainly in the subareolar region (n=30). 32 cases were diagnosed with invasive breast carcinoma of no special type, 3 were invasive special types (2 mucinous and 1 micropapillary), 3 were invasive encapsulated papillary carcinomas and 7 were in situ lesions. Pertaining to invasive carcinomas, 33 were Luminal A, 4 were Luminal B and 1 was triple-negative; 15 had lymph node metastasis (sentinel/axillary nodes) and 4 had distant metastasis reported. To date, 17 patients passed away but it was not possible to evaluate overall survival since most cases did not have information regarding cause of death.

Conclusion: Our study provided data consistent with current knowledge of MBC, with the majority of cases being invasive breast carcinomas of no special type, with a higher frequency of Luminal A molecular subtype; we additionally concluded that most cases were classified as stage I. Noticeably, this cements our understanding of these neoplasms and while female breast carcinomas remain the main source of evidence for treatment algorithms, further research is needed on the optimization of management and therapeutic decision-making in men.

PS-02-006

One-step-nucleic-acid amplification (OSNA) for intraoperative evaluation of sentinel lymph node in breast cancer patients treated with neoadjuvant therapy

A. Cordoba*, A. Pasco, A. Larrea, I. Amat, R. Beloqui, T. Labiano, D. Guerro Setas

*Complejo Hospitalario de Navarra, Spain

Background & objectives: The evaluation of sentinel node (SN) in breast cancer (BC) by one-step-acid-nucleic-amplification (OSNA) after neoadjuvant treatment (NAT) is controversial. We evaluate the results obtained from the incorporation of OSNA for the study of GC in BC patients treated with NAT

Methods: Since June 2018, a total of 163 BC patients have undergone surgery after NAT. In 42 of them, GC study was performed intraoperatively using the OSNA method. Data on the primary tumour, its phenotype, response grade, GC involvement, axillary involvement in positive cases and post-neoadjuvant cytokeratin 19 are studied.

Results: OSNA was feasible in all the 42 patients, displaying grade 1, 2 and 3 in 1, 20 and 21 cases, respectively. One case was luminal A, 6 luminal B phenotype, 16 luminal B-HER2, 8 pure HER2 and 11 triple negative. They showed a Miller-Payne grade 5,4,3 and 1 in 25, 4, 12 and 1, respectively. All the cases with residual tumour were Cytokeratin 19 positive.

Nodes studied by OSNA were negative in 34 patients. Isolated cell group, micrometastases and macrometastases were detected in 1, 5, and 2 cases, respectively. Lymph nodes at subsequent lymphadenectomy were negative in 7 cases and micrometastasis was observed in one case.

Conclusion: it is necessary to detect small metastases after NAT to be treated with lymphadenectomy. We consider that OSNA has all the characteristics that have led to its implementation in non-NAT:

-It is carried out intraoperatively and allows the study of the whole lymph node, avoiding surgery.

-It allows the detection of small metastases associated with false-negative cases.

-The only disadvantage we observe is the impossibility of obtaining the residual cancer burden (RCB) in positive patients, although we can determine the RCB-Class.

PS-02-007

Low grade adenosquamous carcinoma: prevalence in our centre and literature review

P.E. Dacosta Escobar*, D.S. Melgar Rivera, L. Naranjo Ruiz-Atienza, S. Ramón y Cajal-Agüeras, V. Peg Cámara

*Vall d'Hebron University Hospital, Spain

Background & objectives: Metaplastic breast carcinoma corresponds to 0.2-1% of all infiltrating breast carcinomas. We review metaplastic carcinomas diagnosed in our centre the last 7 years, low-grade adenosquamous carcinoma (LGASC) among them, to see their prevalence and clinical or immunohistochemical differences.

Methods: A retrospective study has been carried out of all the breast tumours in our centre diagnosed between 2014 and 2021 and the age at diagnosis was collected as well as the immunohistochemical study of biomarkers (hormone receptors, HER2), P53 and Ki67.

Results: 29 metaplastic carcinomas were identified, 2 cases (6.9%) corresponded to LGASC, 10 (34.5%) to sarcomatoid carcinomas, 9 (31%) to squamous carcinomas, 7 (24.1%) to spindle cell carcinomas, 8%) and 1 (3.4%) to fibromatosis-like carcinoma. The hormone receptors were negative in 89.7% of the cases (100% in the case of LGASC) and P53 showed an altered pattern in 37.9% (50% in LGASC). The average Ki67 was 53.3% [5-95], being 6.5% in the LGASC.

Conclusion: LGASC is a rare tumour within metaplastic breast carcinoma, with 2 cases identified in the last 7 years in our centre. Their age of onset was higher than the average for metaplastic carcinomas and, although they showed a triple negative immunohistochemical profile, their low proliferative index (6.5%) stood out.

PS-02-008

Circulating soluble HLA-G is increased in HER2+ breast cancer patients: a meta-analysis

I. Zidi, K. Tizaoui, S. Dhouioui*, H. Ouzari, N. Boujelbene

*Laboratory Microorganismes and Active Biomolecules, Sciences Faculty of Tunis, University Tunis El Manar, Tunisia

Background & objectives: Soluble plasmatic molecule HLA-G(sHLA-G) is often associated with aggressive cancer types. We aimed to understand the real implication of sHLA-G in aggressive breast cancer (BC), and to resolve the limitation of insufficient statistical power and reduced sample size in individual studies.

Methods: A comprehensive systematic literature search in Pubmed, Medline, Cochrane, Embase, and Web of Science databases was performed to look up for relevant studies. We identified 5 studies with a total of 401 BC patients and 298 healthy controls. The study of sHLA-G levels association to HER2 status is determined by calculating standardized mean differences (SMD) and the corresponding 95% confidence interval(CI).

Results: In overall population, sHLA-G is statistically increased in HER- BC patients as well as in HER+ BC patients compared to healthy controls (Respectively: SMD=1.964; %95CI= 0.368-3.560, P=0.016 and SMD=1.459; %95CI=0.058-2.860, P=0.041). In overall population, the sHLA-G is slightly higher in patients with HER+ vs. HER- without significance (P=0.411). Interestingly, Asians demonstrated significant increase of sHLA-G in HER+ patients compared to HER- patients (SMD=0.477; %95CI=0.104-0.849, P=0.012). This increase may explain the aggressiveness and the rapid progression of HER2+ BC compared to HER2- BC. However, this result should be taken with cautious because of reduced meta-analysed studies.

Conclusion: Our meta-analysis revealed an increased sHLA-G levels in patients expressing HER2 compared to patients HER2- and healthy controls. Our findings suggested the complementary targeted therapy against HER2 and HLA-G in BC expressing HER2 and high sHLA-G levels. Further larger studies and well-designed studies still needed to clearly establish our findings.

PS-02-009

A study on tumour-infiltrating lymphocytes, PD-L1 and BRCA1 immunohistochemical expression in basal-like subtype of breast cancer

P. Dimitrova*, S. Popovska, I. Ivanov

*Medical University, Pleven, Bulgaria

Background & objectives: The aim of the study was to determine basal-like subtype of breast cancer (BC), its tumour expression of breast cancer 1 (BRCA1) protein, the predominant type of lymphocytes and the expression of programmed death ligand 1 (PD-L1) by immune cells.

Methods: We studied 100 patients with invasive BC, grouped into four surrogate molecular subtypes - Luminal A-like and Luminal B-like, HER2 positive non-luminal and triple negative (TN), determined by immunohistochemical (IHC) method.

IHC was performed to find basal-like subtype of BC, to distinguish PD-L1 and BRCA1 antigens and to detect subtypes lymphocytes, using CD20, CD3, CD4, CD8 and FoxP3 antibodies.

Results: In our cases, the basal-like BC were mainly TN (p<0.05), mostly with special histological subtypes (p=0.036). Their immune response was represented predominantly by high concentration of intratumoral cytotoxic CD8+ T-lymphocytes (p<0.05) and stromal PD-L1 positive immune cells (p=0.008). In these tumours, the BRCA1 expression was more often absent in the tumour cells (p<0.001).

The basal-like subtype of BC and IHC negative expression of BRCA1 were associated with <5-year survival (p=0.001 and p=0.017, respectively).

Conclusion: The established dependencies can be incorporated in a prognostic algorithm and predictive morphological screening, allowing better selection of patients with BC for subsequent genetic analysis of BRCA1 gene and for application of appropriate therapy.

PS-02-011

Vacuum assisted breast biopsy: diagnostic and therapeutic

D. Doutel*, S. Santos, G. Freire, J. Marques, S. André

*Instituto Português de Oncologia de Lisboa Francisco Gentil, Portugal

Background & objectives: Vacuum-assisted breast biopsy (VAB) plays a diagnostic and therapeutic role. This study aims to evaluate the efficacy of this procedure in the management of breast lesions at a single institution.

Methods: We carried out a retrospective study, of 221 VAB (guided by stereotaxis or ultrasound) performed at a single institution over 15 months. We reviewed the imaging characteristics of the lesions, as well as the histological slides from VAB and respective surgical specimen, when available. Post VAB surgery was performed based on the imagiological follow-up.

Results: Imaging characteristics pre-VAB: microcalcifications (56,1%); nodules (33%); architectural distortion (4,5%) and density asymmetries (2,3%).

Diagnosis by VAB: benign (44,8%); uncertain malignant potential/B3 (22,2%) including 23 papillomas (10.4%); ductal carcinoma in situ/DCIS (23,5%); invasive carcinoma not otherwise specified/IC (9,5%).

In 70 cases (31,7%) post-VAB surgery was necessary: 2,8% were benign lesions; 15,7% B3 lesions; 54,3% DCIS; 27,1% IC.

No malignancy was found on the surgical specimens of benign and B3 lesions. Of 19 papillomas, only 1 was incompletely excised with VAB.

In DCIS' surgical specimens, there was no residual lesion in 5,2%; microinvasive carcinoma was found in 10,5% and IC in 10,5%, one of these with a 3 mm axillary metastasis.

Conclusion: The low percentage of cases submitted to surgery post-VAB proves its efficacy in the management of benign and also in B3 lesions, with emphasis in the total excision of papillomas. Of the DCIS cases that went through surgery, we found no residual tumour in 5,2% and malignancy in 21,1%, half of these with microinvasion.

PS-02-012

Denosumab as inmunomodulator in early breast cancer: preliminary results of a randomized window of opportunity clinical trial D-BIOMARK (NCT03691311)

G. Ippoliti*, A. Vethencourt, T. Eva, A. Feu Llauradó, C. Taco, E. Guerra, J. Azcárate, A. Petit, A. Gumà Martínez, C. Falo, X. Matias-Guiu, T. Soler-Monsó, E. Gonzalez-Suarez

*Pathology Department, Bellvitge University Hospital, IDIBELL, Barcelona, Spain

Background & objectives: RANK pathway inhibition could prevent and/or treat breast carcinoma (BC) and regulate the tumour immune crosstalk in BC. We are running D-BIOMARK, a prospective, randomized pre-operative study evaluating denosumab (anti-RANKL) and its biological effects in early-stage BC.

Methods: Early-stage HER2-negative-BC, candidates to tumour excision as first therapeutic approach were included. Patients were randomized into two groups: 2:1 to denosumab: control (no treatment). Experimental arm received 2 doses of subcutaneous denosumab 2-4weeks before surgery. Clinicopathological parameters were recorded. Ki67, cleaved caspase-3 and stromal tumour infiltrating lymphocytes (TILs) were assessed in biopsy and surgical resection specimen (pre- and post-denosumab).

Results: We present results from the first 36 patients enrolled out of 60. Clinical and tumour characteristics were well balanced between the groups. No clinically relevant differences in Ki67 or cleaved caspase-3 were observed after denosumab treatment. Interestingly, an increase of TILs was observed in the denosumab treated group (p=0.03, Paired t test), but not in the control group (p=0.80). A 33% of patients treated denosumab showed a ≥10% increase in TILs vs 0% in the control group (p =0.05).

Conclusion: Short term neoadjuvant denosumab increases TILs in early BC.

PS-02-013

Insulinoma-associated protein 1 (INSM1) expression in breast carcinomas with neuroendocrine morphologies: application and future prospective

T. Kawasaki*, K. Kaira, Y. Nakamura, H. Imai, T. Kondo, H. Nagai, A. Enomoto, M. Saitoh, T. Tashima, Y. Tanisaka, Y. Horita, T. Hamaguchi, H. Kagamu

*Saitama Medical University, Japan

Background & objectives: INSM1 was recently demonstrated to be a better diagnostic and prognostic indicator for small cell pulmonary carcinoma than the traditional ‘gold-standard’ neuroendocrine (NE) markers, i.e. chromogranin A and synaptophysin.

Methods: Herein, for the first time, we present three cases with NE phenotype mammary neoplasms in which the NE nature of the tumours was confirmed solely by INSM1. This is also the first analysis to use INSM1, a promising antibody with high sensitivity and specificity, in the field of breast oncology.

Results: Three patients were, respectively, 42-, 58- and 64-year-old Japanese women with breast tumours showing characteristic NE morphologies: 1) Neuroendocrine tumour, grade 2, 2) Cellular mucinous carcinoma, and 3) Neuroendocrine ductal carcinoma in situ. On immunohistochemical examinations, these malignancies showed diffuse nuclear expressions of INSM1, whereas chromogranin A and synaptophysin staining did not correspond to distinct NE features in the neoplastic cytoplasm, despite appropriate positive and negative controls having been provided for these NE stained sections. In addition, we could not detect INSM1-reactive cells in breast parenchyma surrounding the tumours.

Neuroendocrine neoplasms (NENs) could be regarded as a rare, distinctive type of aggressive mammary carcinoma.

Conclusion: Intriguingly, in the lung oncology field, it was very recently reported that outcomes were significantly poorer in NEN patients with high-INSM1 than those with low-INSM1 reactivity.

Based on the establishment of INSM1 accompanied by our current immunohistochemical results, the frequency of detecting NE differentiation in systemic neoplasms, including breast NENs, is anticipated to increase. Our observations might ultimately contribute to the development of novel treatments including molecular-targeted therapies for these invasive tumour entities.

Funding: Grants-in-Aid for Scientific Research (No. 21K06910 and No. 16K08654) from the Japanese Ministry of Education, Culture, Sports, Science and Technology and the NHO Grant (H29-NHO-01).

PS-02-014

Expression of prolactin receptors does not affect the development of benign breast pathology

O. Kolomiiets*, O. Yazykov, I. Lukavenko, A. Piddubnyi, V. Andriushchenko, A. Romaniuk, R. Moskalenko

*Sumy State University, Ukraine

Background & objectives: Recently, attention has been given to the study of prolactin receptors (PRL-R) on the development of benign breast tumours (BBT). The aim: to investigate the relationship between PRL-R expression and the development of BBT.

Methods: 16 samples of BBT and 16 samples of intact tissue were taken for the study. We considered serum PRL levels, according to which patients were divided into two groups: group I - with normal serum prolactin (8 women) and group II - with elevated serum prolactin (8 women). BBT tissue was examined using histological, immunohistochemical methods and Western blotting.

Results: The middle age of the women in the BBT study was 27.9 ± 1.55 years, ranging from 19 to 39 years. Expression rates of PRL-R in BBT tissue (39.97 ± 2.1) and intact MG tissue (35.56 ± 3.6) did not differ significantly (p> 0.05). In women of group I, a strong positive association was found between PRL-R expression in BBT tissue and serum prolactin levels (p <0.05; p = 0.8). Comparison of middle PRL-R expression values in benign tumour tissues and intact MG tissues of patients with elevated PRL levels did not show a significant difference between these indicators (p> 0.05).

Conclusion: Therefore, the level of PRL-R expression does not affect benign pathology of the breast.

PS-02-015

NDRG1 and lymph nodes status in breast cancer

V. Kometova*, L. Mikhaleva, M. Rodionova, V. Rodionov

*V.I. Kulakov NMRC of OGaP, Russia

Background & objectives: N-myc downstream-regulated gene1(NDRG1) is widely described as a distant metastasis suppressor in breast cancer(BC). However, the related mechanism has not been fully discovered yet. In our study, we purposed to investigate the relationship between NDRG1 and lymph node BC metastasis.

Methods: NDRG1 levels in tissue microarrays from 358 BC patients were evaluated by immunohistochemical staining with NDRG1 (ЕР200, Abcam, USA). NDRG1 staining was predominantly cytoplasmic/membranous. NDRG1-scoring was done according to the German semi-quantitative scoring system (intensity and percentage of stained tumour cells). Tumours with score 1–4 were considered as negative (NDRG1-low), whereas tumours with score 5–12 were considered as positive (NDRG1-high).

Results: NDRG1-high BC tumours were significantly more often detected (136 cases, 60.2%) in the patients group without lymph nodes metastases(group 1) than in those with metastases(group 2)(62 cases, 47%)(p=0.015). The absence of NDRG1 expression was observed with the same frequency in the two compared groups(18.1%). The intensity of NDRG1 expression was higher in the group 1(25.7%) compared to the group 2(21.2%). No significant difference was obtained(p = 0.576). The significant difference was found in the two compared groups for moderate and weak NDRG1 expression. In the group 2 weak intensity expression of the marker was more often observed (34.8%), while in the group 1 moderate NDRG1 expression was more common (34.5%).

Conclusion: NDRG1 was a significant independent prognostic factor of lymph nodes metastases in BC. The intensity of the marker expression was statistically significant (p=0.015). In samples with NDRG1- moderate expression the risk of lymph node metastasis was lower than when the staining of tumour cells was weak (p=0.045). NDRG1-low expression has a reverse correlation with breast cancer metastasis and progression, and may serve as a predictive biomarker of lymph node involvement.

Funding: НИОКТР АААА-А18-118053190016-7

PS-02-016

MMP-2 expression in breast cancer and its association with molecular subtypes and clinicopathological features

V. Kometova*, L. Mikhaleva, M. Rodionova, M. Dardyk, V. Rodionov

*V.I. Kulakov NMRC of OGaP, Russian Federation

Background & objectives: Matrix metalloproteinase-2(MMP-2) is gelatinase that plays a role in invasion and metastasis of cancer through the destruction of basal membrane and extracellular matrix. The study is aimed to investigate MMP-2 expression levels in breast cancer(BC) and their relationship with molecular subtypes.

Methods: MMP-2 expression levels were studied in 358 tissue microarrays of BC specimens and their association with 5 molecular subtypes was evaluated by immunohistochemical cytoplasmic staining with MMP-2 (EPR1184, Abcam, USA). MMP2-scoring was done according to intensity of stained tumour cells. The staining scores for MMP-2 were negative in 96 cases(26.8%), mild in 184 cases(51.4%), and strong in 78 cases(21.8%).

Results: MMP-2 expression was increased in BC with HER2/neu overexpression, regardless of hormon receptor status. Strong MMP-2 expression was detected in 66.7% of luminal B HER2-positive subtype BCs and in 53.3% of non-luminal HER2-positive BC subtype. Only 1 case of BC with HER2/neu overexpression was MMP2-negative (p<0.001). There were only 10 (6.2%) cases with strong MMP2-expression and 76 (79.2%) MMP2-negative cases in luminal-A subtype BC. Regarding luminal-A subtype, MMP-2-negative and mild expression was observed in 45.8% and 93.8% cases respectively in comparison to luminal-B Her2-negative BC subtype (6.7% and 73.3%) (p<0.001). The number of MMP2-negative cases was lower than in TNBC (6.7% and 30.6% respectively), but without statistical significance(p=0.158).

Conclusion: MMP2-expression is associated with molecular BC subtypes (p<0.001). MMP2-negative BC positively correlates with luminal-A subtype. MMP-2 expression is increased in TNBC and in cases with HER2 over-expression (p<0.001). Furthermore, strong MMP-2 expression correlates with larger tumour size (p<0.001), high-grade (p<0.001) and tumours with lymph nodes metastases (p<0.001). No correlation was found between MMP-2 expression and patient’s age(p=0.061), tumour localization(p=0,113), number of tumour nodes(p=0.619), hystologic BC type (p=0.417). These results suggest that MMP-2 plays a role in the biology of BC.

Funding: НИОКТР АААА-А18-118053190016-7

PS-02-017

Heterogeneity of Ki67 expression in local metastases of breast cancer depends on the surrogate subtype of the primary tumour

K. Konyshev*, S. Sazonov

*Institute of Medical Cell Technologies, Ural State Medical University, Russia

Background & objectives: Ki67 is an important prognostic and predictive marker for breast cancer. Its heterogeneity could affect the treatment results. Objective of the study: to discover Ki67 level stability in local metastasis of Luminal A-like and Luminal B-like breast cancer primary tumour.

Methods: 66 patients having breast cancer with local metastases and Luminal A or Luminal B surrogate subtype of primary tumour were included in the study. Antibodies to ER (1D5), PR (PgR636), Ki67 (MIB-1) and Her2/neu (4B5) were used. Changes of Ki67 expression (threshold – 30%) in primary and metastatic tumours were counted and compared in groups with different primary tumour subtypes.

Results: In the group with Luminal A subtype of primary tumour Ki67-status of primary tumour and metastases was discordant in 8 of 50 cases (16,0%, 95% CI 7,6-29,7%), while in group with Luminal B subtype – in 11 of 16 cases (68,7%, 95% CI 41,5-87,9%). The difference of discovered frequencies is statistically significant (Fisher exact probability test) (p<0,01).

Conclusion: Proliferation status of breast cancer is discordant in primary and metastatic tumour depending on the surrogate subtype of the primary tumour. In cases with Luminal B subtype Ki67 status of the metastasis changes more frequently than in cases with Luminal A subtype of the primary tumour.

PS-02-019

Study on the heterogeneity of expression of PD-L1 (Ventana SP142) in breast cancer in space and time

J. He, Y. Liu*

*The Fourth Hospital of Hebei Medical University, China

Background & objectives: Tumour has a certain degree of heterogeneity, which brings a challenge for clinicians to choose PD-L1 detection time for breast cancer patients. Therefore, the heterogeneous expression of Ventana PD-L1 (SP142) in breast cancer needs to be studied in depth.

Methods: 124 surgical specimens, 5 tissues were penetrated in each case. 298 cases of primary breast cancer and its matched metastases were stained with PD-L1 to explore the differences in expression. 71 cases of PD-L1 positive invasive breast cancer specimens were included at different temperatures and different time nodes. Compare the expression of PD-L1 with the corresponding fresh slices.

Results: When the number of punctured tissues increased from 1 to 5, the κ value of PD-L1 expression and PD-L1 expression in surgical specimens gradually increased from 0.165 to 0.615, and κ was 0.499 for 3, reaching a moderate consistency. The positive rate of PD-L1 in different metastatic organs is different. With the extension of the storage time of paraffin sections, the PD-L1 antigen is gradually lost, and the positive rate gradually decreases. The expression of PD-L1 in slices stored at room temperature for 1 and 2 weeks is more consistent than that of fresh slices (ICC≥0.9).

Conclusion: The expression of PD-L1 in primary breast cancer and paired metastatic breast cancer is different, and the expression of PD-L1 in metastases needs to be reassessed. Long-term storage of paraffin sections will cause the expression level of PD-L1 to decrease and refrigerated storage at 4°C or -20°C is recommended, and the storage time should not exceed one month.

PS-02-020

Changes in the positive rate of HER2 expression may indicate the progression of early breast cancer

D. Han, M. Yue, M. Zhao, Y. Liu*

*The Fourth Hospital of Hebei Medical University, China

Background & objectives: To explore the relationship between the expression of HER2 and clinicopathological characteristics in patients with microinvasive breast cancer and T1a breast cancer. To analyse the consistency of HER2 expression in carcinoma in situ and invasion foci.

Methods: 217 cases of breast microinvasive carcinoma and T1a patients admitted to the hospital from January 2015 to June 2020 in the Fourth Hospital of Hebei Medical University were collected. Interpret the HER2 expression status of the carcinoma in situ and the infiltrated area respectively. Combining pathological features and morphological features to construct a nomogram to predict the HER2 expression status.

Results: High nuclear grade, comedy type necrosis, high TILs infiltration and high proliferation index are more likely to have HER2 positive expression. There was no significant difference in the expression of HER2 in microinvasive breast carcinoma and T1a in carcinoma in situ and invasive area. The overall agreement rate of HER2 expression of carcinoma in situ and invasive area was 97.7%.The feature with the strongest correlation with the HER2 positive rate is the diameter of the invasion foci. When the diameter of the invasion foci>2mm, the positive rate of HER2 decreases significantly (52.6%-16.1%, p<0.001). The molecular type has changed (c2=9.725, p=0.045), and the lymph node metastasis rate is increased (2.6%-8.9%, p=0.426).

Conclusion: The HER2 expression in the carcinoma in situ area can be referred to. Compared with T1a stage breast cancer with an invasion foci of 1-2 mm in diameter, breast cancer patients with an invasion foci of 2-5 mm in diameter are more malignant, and HER2 targeted therapy is recommended for HER2-positive breast cancer patients with an invasion foci of 2 to 5 mm in diameter.

PS-02-021

Establishment and verification of a prognostic prediction model for non-pCR patients after neoadjuvant treatment of breast cancer

J. Li, Y. Liu*

*The Fourth Hospital of Hebei Medical University, China

Background & objectives: The purpose is to establishment and verification of a prognostic prediction model for non-pCR patients after neoadjuvant treatment of breast cancer.

Methods: Patients who were diagnosed with invasive breast cancer from 2009 to 2017 and were surgically removed after neoadjuvant therapy. All pathological results included histological grade, Tils, ER, PR, HER2 and Ki67. R language is used to calculate the calibration degree and ROC curve of the prediction model in the training set and the verification set.

Results: In the training set, the prediction model's 3-year and 5-year survival rate AUC values were 0.93 and 0.80, and the RCB classification 3-year and 5-year survival rate AUC values were 0.69 and 0.65. Relative to the RCB classification, the prediction model can more accurately predict the OS of non-pCR patients after neoadjuvant treatment. The same results are also shown in the classification of HR, HER2+ and TN. The RCB classification predicts HR 3-year and 5-year survival rates AUC values of 0.77 and 0.72; predicted HER2+ 3-year and 5-year survival rates AUC values of 0.79 and 0.62; predicted 3-year and 5-year survival rates of TN group AUC value of 0.83, 0.69.

Conclusion: We have combined a variety of prognostic factors related to breast cancer through R software and developed a more accurate prediction model than RCB classification to evaluate the prognosis of non-pCR patients after neoadjuvant treatment of breast cancer and provide further clinical treatment Provide a basis for decision-making.

PS-02-022

Immunohistochemistry for NDRG1 and its phosphorylated form and its relationship with triple negative breast cancer biological features and behaviour

R.J. Luque*, L. Molina-Jimenez, A. Sabio González, A. Lopez-Tejada, C. Cantero-González, A. Gonzalez-Gonzalez, E. Vazquez-Gonzalez, F.E. Cara, J.L. Blaya-Canovas, R. Lopez-Garcia, A. Navarro-Ocon, C. Martinez de Carvajal-Rodriguez, S. Granados-Principal

*UGC Anatomía Patológica, Hospital Universitario de Jaén, Spain

Background & objectives: Triple Negative Breast Cancer (TNBC) is the most aggressive molecular type of breast cancer. Herein we assess the prognostic role of NDRG1 (a gene of the TGF-beta pathway) and its phosphorylated form (pNDRG1) in a series of TNBC.

Methods: Eighty-three cases of TNBC (All female, age: 23-86 years, follow up: 66-264 months) were included in this study.

Immunohistochemistry for NDRG1 and pNDRG1 was performed, scoring intensity and extension of the staining on digital images obtained with a 3DHISTECH preparation scanner.

Statistical analysis assessed the association of the degree of staining with survival, development of recurrence, metastases, and histological parameters.

Results: Seventy-three cases were infiltrating ductal carcinoma (85.9%), frequently in stages pT1 (31, 36.5%) and pT2 (36, 42.4%) and there were lymph node metastases in 23 cases (28%) and distant metastases in 1 case (1.2%). 34 (40%). patients died from disease (DFD) during follow-up.

NDGR1 and pNDRG1 was detected in 67.5% and 67.5%, respectively mainly at cytoplasmic level, with a lesser nuclear staining.

Nuclear NDRG1 expression is higher in DFD (11.92 vs 2.99%, p = 0.03) and cytoplasmic in recurrences (35.82 vs 19.99%, p = 0.04). On the contrary, pNDGR1 is higher in survivors without disease (30%) compared to active disease (3.88%) or DFD (18.05%), although without statistical significance.

Conclusion: NDGR1 expression in TNBC seems to be associated with parameters of tumour aggressiveness, in contrast to the expression of its phosphorylated form, which shows a trend to be expressed in cases with better biological behaviour. Further studies on larger series are needed to clarify its prognostic role in this area.

PS-02-024

Digital image analysis is a robust method for evaluation of tumour-associated macrophages in breast cancer

K.H.L. Nielsen*, P.S. Nielsen, T. Tramm

*Dept. of Pathology, Aarhus University Hospital, Denmark

Background & objectives: Tumour-associated macrophages (TAMs) may be of prognostic value in breast cancer. The objective was to investigate agreement between 1) estimation of CD68+ TAMs by “eye-balling” and digital-image-analysis (DIA) and 2) assessment of TAMs on tissue-micro-arrays (TMAs) and whole-slide-sections (WS).

Methods: Tumour-containing tissue blocks and TMAs (1 core/patient) were available from 1167 BC patients. Immunohistochemistry for CD68 were performed on TMAs (991 pts.) and on corresponding WS from 234 patients. Fraction of CD68+ TAMs was estimated semi quantitatively by 2 observers (KH, TT) using light microscopy (“eyeballing”) and quantitatively by DIA on scanned slides as a continuous area-fraction.

Results: Evaluation of CD68 was successful in 991/1167 TMA cores and 223/234 WS. Interobserver agreement for “eyeballing” on WS was moderate with an intraclass-coefficient (ICC) of 0.72 (95%Cl: 0.65-0.78). Kappa coefficient was 0.40 when grouping the results into 6 categories (0-0.01, 0.02-0.10, 0.11-0.20, 0.21-0.30, 0.31-0.40, >0.41), increasing to 0.53 for 3 categories (0-0.10, 0.11-0.30, >0.31). A minority of tumours(21/991) showed high level of TAMs (> 0.31).

Correlation between TMAs vs. WS was highly significant by ”eyeballing” as well as by DIA with Spearman correlation coefficients of 0.55 and 0.62 (p<0.0001), respectively. A strong significant correlation was found between DIA and “eye-balling” for both WS and TMAs (p<0.0001, Kruskal-Wallis test).

Conclusion: The interobserver agreement by “eye-balling” was moderate, whereas correlation between “eye-balling” and DIA was highly significant. The association between TMAs and WS by DIA and “eye-balling” was found to be highly significant indicating that CD68-assesment can be performed on, e.g., biopsies. This indicates that DIA may be a useful tool for estimating TAMs with the perspective of delivering a more reproducible and quantifiable estimate and securing the analytical validity of CD68 as a potential biomarker.

Funding: Danish Cancer Society (R148-A10067-16-S46)

PS-02-025

Molecular phenotype of breast cancer in women under 35 years old

O. Reshetnikova*, S. Korenev, I. Goryanikova, O. Zinchenko, O. Teleshova, O. Kononenko, E. Burgelo, Y. Shmurakov, D. Kolesnikov

*Immanuel Kant Baltic Federal University, Russia

Background & objectives: Breast carcinoma is the most common malignant tumour in young women, with higher mortality rate compared with older population. The aim of present study was to reveal the peculiarities of breast cancer’ molecular phenotype in patients under 35 years old.

Methods: We examined the pathologic features and molecular tumour’ phenotype in 35 young women (aged ≤35years) with invasive breast cancer. Medical records were reviewed for clinical characteristics. Breast tissue histological slides H&E stained observed under a microscope. Hormonal status, Her2/neu status and Ki 67 were determined by immunochemical (IHC) staining. Histologic grading of breast carcinoma was performed by Elston and Ellis method.

Results: Among 1009 cases of breast cancer 35 young women were selected for study group. The most frequent histological diagnosis was invasive carcinoma of a nonspecific type (91%), invasive lobular carcinoma was established in 8% of cases and 1 % -was mucous cancer. Analysis of IHC studies revealed the predominance of the molecular genetic subtype - luminal B HER2 positive with a high index of proliferative activity Ki-67 (52%). Luminal A was 32% of cases, triple negative subtype was established in 8% of cases and HER2-positive in 8% of cases. Most often, the molecular genetic subtype luminal B HER2-positive corresponded to invasive nonspecific cancer with a high index of proliferative activity.

Conclusion: Our findings have shown that the group of young women presented with a different variation of molecular phenotypes compared to the general population of women with breast carcinoma. The most common molecular genetic subtype of breast cancer in young women under 35 y.o. was luminal B HER2-positive molecular phenotype. These results are discussed with regard to the pathogenesis and prognosis of the neoplasia in young women. The data obtained should be taken into account when developing the adjuvant therapy algorithm.

PS-02-026

Immunohistochemistry alone may represent a cost-effective alternative for HER2 status assessment on biopsy

C. Rossi*, S. Fraticelli, E. Boveri, G. Di Giulio, M. Fanizza, A. Sgarella, A. Ferrari, E. Ferraris, T. Richard, E. Bonzano, M. Lucioni

*Unit of Anatomic Pathology, Department of Molecular Medicine, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Italy

Background & objectives: ASCO/CAP guidelines recommend HER2 status assessment on newly diagnosed breast cancer due to its prognostic and predictive impact. Currently, a combination of immunohistochemistry (IHC) and in-situ hybridization (ISH) is recommended. We evaluated the reproducibility of HER2 assessment with IHC alone.

Methods: At our Institution, 1654 patients underwent both bioptical and surgical procedure between January 2014 and December 2020. Patients with in situ, microinvasive or multicentric carcinomas, and patients treated with neoadjuvant therapy were excluded. The final cohort comprised 923 patients. ErbB2 IHC staining was performed with Dako AcP A0485 on OMNIS platform and scored according to 2018 guidelines.

Results: Overall concordance for ErbB2 IHC was 88.95% (821/923), in line with the literature-reported values for IHC alone. Revision of the 102 discordant cases revealed that only 7 (<1%) had the potential to significantly impact on the therapeutic choices for the patient (either negative/equivocal to positive or positive to negative changes between biopsy and surgical specimen). All other discordant results were between negative and equivocal status and, according to current guidelines for neoadjuvant treatment, would have not resulted in either over-treatment or under-treatment of the patient.

Conclusion: HER2 status has a tremendous impact on the prognosis and treatment of the patient and must be assessed in a timely and precise manner to ensure the best treatment is administered. Although the combination of IHC and ISH is to be preferred for its accuracy, our data suggests that IHC alone could be a valid alternative in settings in which cost or availability do not allow for ISH testing on all newly diagnosed cases, restricting ISH testing to equivocal cases.

PS-02-027

Semiquantitative evaluation of TILs in breast cancer shows differences among histotypes and tumour grade.

C. Rossi*, A. Bonometti, E. Boveri, G. Di Giulio, F. Ballati, A. Sgarella, A. Della Valle, E. Ferraris, G. Rizzo, M. Lucioni

*Unit of Anatomic Pathology, Department of Molecular Medicine, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Italy

Background & objectives: Current research in tumour microenvironment (TME) of breast cancer focuses mainly on molecular subtype and receptor status. In this work, we compare TME characteristics between no special type and lobular breast cancer to ascertain if a correlation with histotype exists.

Methods: At our Institution, 1724 patients underwent surgery for breast cancer (January 2012-December 2018). Patients who received neoadjuvant therapy were excluded. A final cohort of 1395 invasive breast cancer was considered; 1047 were diagnosed as no special type, 190 as lobular, and 158 as other histotypes. Stromal tumour-infiltrating lymphocytes (TILs) were assessed semi-quantitatively and grouped into a "brisk" or "non-brisk" category.

Results: Among the 1021 no-special type cases in which TILs were assessed, "brisk" TILs were found to be associated with histologic grade of the tumour: 7% in the G1 group (8/113), 19% of the G2 group (106/548), and 48% of the G3 group (171/360). In contrast, grade did not seem to impact the adaptive immune response in lobular carcinoma, and "brisk" infiltrate showed an analogous distribution: 17% in the G2 group (27/155) and 22% in the G3 group (7/32). This is not unexpected, as the no-special type histotype includes most of the triple-negative and HER2-enriched invasive breast cancer, which are found to be associated with increased TILs.

Conclusion: Our data suggest that in no-special type breast cancer TILs appear to parallel histologic grade and could reflect the increased genomic instability of high-grade cancers. In contrast, lobular carcinoma may represent a subtype of breast cancer in which adaptive immune response is underregulated, possibly underlying a low genomic instability and consequent low burden of neoantigens. As more therapies emerge for which TILs could represent a predictive factor, a more comprehensive understanding of its significance in breast cancer is needed.

PS-02-028

Copy number alteration influences tumour microenvironment in breast cancer

C. Rossi*, A. Bonometti, E. Boveri, G. Di Giulio, M. Fanizza, F. Ballati, A. Sgarella, E. Ferraris, A. Lasagna, M. Lucioni

*Unit of Anatomic Pathology, Department of Molecular Medicine, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Italy

Background & objectives: The introduction of therapies targeting genomic instability (e.g. PARP inhibitors) has made it crucial to gain a deeper understanding of the impact of genomic instability on breast cancer. Here we investigate the relationship of genomic instability with tumour microenvironment.

Methods: At our Institution, 1724 patients underwent surgery for invasive breast cancer (January 2012-December 2018). A cohort of 1003 patients was analysed by immunohistochemistry and grouped based on their molecular subtypes into three copy-number alterations (CNA) patterns identified by Kwei et al. ("simple", "amplifier", and "complex"). Stromal tumour-infiltrating lymphocytes (TILs) were assessed semi-quantitatively and grouped into a "brisk" or "non-brisk" category.

Results: In our cohort, "brisk" TILs were found to be significantly associated with the CNA-associated patterns defined by Kwei et al. Infiltrate was categorized as "brisk" in 15% in tumours belonging to the "simple" pattern (59/402), in 34% of the tumours belonging to the "amplified" pattern (184/534), and in 52% of the tumours belonging to the "complex" pattern (35/67). Although the use of molecular classification as a surrogate for CNAs is not as precise as the actual genetic analyses, the correspondence between these classes and the CNAs-associated pattern is supported in the literature.

Conclusion: Our data suggest that genetic instability could have a role in eliciting a strong stromal lymphocytic response in breast cancer, and we postulate this to be due to an increased number of neoantigens contributing to generate and maintain this response. In light of the current and upcoming therapies targeting genomic instability, the identification of surrogate markers to evaluate this instability, including TILs, will become crucial in the understanding and management of breast cancer.

PS-02-029

Interobserver variability of breast grading in core biopsies

G. Sarra*, S. Ben Slama, N. Ben Othman, A. Lahmar, D. Bacha

*CHU Mongi Slim La Marsa, Tunisia

Background & objectives: Nottingham histologic grading has become widely accepted as a powerful indicator of prognosis in breast cancer. The objective of this study was to evaluate the interobserver variability of this grade in scoring breast cancer in core biopsies among 2 pathologists.

Methods: This is a retrospective study of 65 cases of invasive ductal carcinoma that were independently evaluated by two pathologists and graded according to the Nottingham histologic system. A detailed histopathological assessment was carried out and analysed statistically using the Kappa agreement score.

Results: The mean size of biopsies was 15 mm. There was a substantial agreement among the 2 pathologists in scoring tubular formation, pleomorphism, and final grading (Kappa=0.7, 0.65 and 0.8 respectively). A fair agreement was noted in scoring mitosis (Kappa=0.35).

Conclusion: The interobserver variability of Nottingham grading in scoring breast cancer in core biopsies remains good. The relatively weak agreement in scoring mitosis is secondary to the small size of the micro-biopsies, not covering the 2 mm2 fields necessary to grade this parameter. This often leads to an extrapolation of the number of mitoses.

PS-02-030

High tumour-stroma ratio in oestrogen receptor-positive breast cancer is correlated to poor histopathological parameters

G. Sarra*, S. Ben Slama, N. Ben Othman, A. Lahmar, D. Bacha

*CHU Mongi Slim La Marsa, Tunisia

Background & objectives: In breast cancer, attention has focused on the prognostic value of tumour- stroma ratio (TSR), mainly in the triple-negative subtype. The objective of this study was to determine the prognostic value of TSR in oestrogen receptor (ER) positive invasive breast carcinomas.

Methods: TSR was measured in hematoxylin and eosin-stained surgical specimens of 70 consecutive EP positive breast carcinomas. Scoring percentages were given per 10-fold per image field. Tumours with a low ratio had ≥50% of stroma and a high ratio had <50% of stroma. The relationship of TSR to routinely used prognostic histopathological parameters was analysed.

Results: All tumours were of no special type. The mean age of patients was of 65 years. There was no multifocality. Sixty percent of tumours had a high ratio and 40% a low ratio. High ratio tumours were significantly correlated with large size (p=0.02), grade 3 (p=0.045), presence of vascular invasion (p=0.0034) and lymph node metastasis (p=0.0012). No significant association was found with the mitotic activity index and HER2 status.

Conclusion: High TSR was related to poor histopathological parameters in EP positive breast carcinomas, contrasting data in triple-negative breast cancer, and highlighting the importance of considering ER status when interpreting the prognostic value of TSR.

PS-02-031

Breast cancer in young women: clinicopathological features of 27 cases

G. Sarra*, S. Ben Slama, N. Ben Othman, A. Lahmar, D. Bacha

*CHU Mongi Slim La Marsa, Tunisia

Background & objectives: Breast cancer in young women has gained increased attention with an attempt to improve diagnosis and prognosis. The objectives of this study was to analyse the clinico-pathological features of breast cancer occurring in young women under 30 years.

Methods: We retrospectively studied 27 cases of histologically confirmed breast cancer, collected during 8 years, in gynaecology and pathology departments of our institution. All patients were under 30 years of age at diagnosis. Clinical data, pathological investigations and outcome statistics were analysed.

Results: The average age was 26.5 years. The tumour was T4 in 35% of cases and M1 in 3 patients. Treatment was radical in 60% of cases. Histological type was an invasive ductal carcinoma in all cases (grade III 35 %). Lymph node involvement was noted in 27.5%.Phenotype was:HER2 in 7 cases, triple negative in 8 cases, luminal A and B in 6 cases each. Chemo and radio therapies were performed in respectively 90 and 95% of cases, Hormone and targeted therapies were performed in 40% and 25% of cases respectively. Recurrences were noted in 25% of cases, distant metastases in 45% of cases and disease related dealth in 12% of cases. BRCA1 was positive in 5 patients.

Conclusion: Breast cancer in young women seems to be highly heterogeneous and has potentially aggressive and complex biological features.

PS-02-032

Association between positive lymph node ratio and prognostic clinicopathologic factors in breast cancer with axillary involvement

T. Soylemez Akkurt*, B. Pehlivanoglu, B. Calim Gurbuz, H. Izol Ozmen, C. Tanik

*Basaksehir Cam and Sakura City Hospital, Turkey

Background & objectives: Recently, the ratio of the number of the metastatic lymph nodes (LNs) to the total number of examined LNs (LNR) has been suggested as a prognostic factor in breast cancer. Here, we investigated the association between clinicopathological parameters and LNR.

Methods: This study included 83 consecutive female patients with LN-positive breast cancer who underwent partial/radical mastectomy with axillary LN dissection. Clinicopathological parameters were retrospectively retrieved from patient records. LNR was defined as the ratio of positive nodes to total number of examined nodes. The relationship between LNR and clinicopathological parameters was statistically analysed.

Results: Median age was 51±1.7 years (range 30-82). The mean number of LNR and positive LNs was 0.3 (0.04-1) and 4.4 (range 1-27), respectively. More than half of the patients (51.8%, n=43) were pN1a. In univariate analysis, larger tumour size (advanced pT), presence of lymphovascular invasion (LVI), extranodal extension (ENE), and stage were significantly associated with higher LNR (p<0.05). A positive LN number of ≥4 was significantly associated with higher mitotic scores, advanced pT, presence of LVI and perineural invasion, and ENE (p<0.05). However, in multivariate logistic regression analysis, only ENE was significantly associated with LNR and positive LN number (p=0.011, OR=5.05, 95% CI=1.458–17.511, p=0.003, OR=7.135, 95% CI=1.942–26.216, respectively).

Conclusion: Unfavourable histopathological features were associated with LNR and the number of positive nodes but we could not verify most of these associations by multivariate analysis due to small number of patients. On the other hand, the significant association of ENE with LNR and the presence of ≥4 positive LNs was confirmed by multivariate analysis. We speculate that the presence of ENE in sentinel LNs may provide a clue in predicting pN but prospective studies are needed to test this hypothesis.

PS-02-033

Changing trends in hormone receptor and Her2 rates in breast cancer overtime

M. Sughayer*, H. Abdel-Razeq, G. Al-Jussania, A. Alsughayer, T. Dabbagh, S. Alhassoon, D. Al-Rimawi

*KHCC, Jordan

Background & objectives: In 2006 we published our breast cancer oestrogen receptors (ER)/progesterone receptors (PgR)/Her2 rates in Jordan which were 50.8%/57.5%/17.5% respectively for ductal and 68%/90.9%/13.6% for lobular. An update of these rates is warranted in view of remarkable socioeconomic and technical changes.

Methods: 1185 breast cancer cases were accessioned in our department between January and December 2018. ER/PgR and HER-2/neu results were retrospectively collected from patients’ pathology reports. They were originally evaluated by immunohistochemistry (IHC). In addition, evaluation of HER2/neu was done by fluorescent in-situ-hybridization in IHC equivocal cases. The testing was originally interpreted according to the 2013 CAP-ASCO guidelines.

Results: 867 (73.2%) cases were ductal, 669 (77.2%) of which were ER-positive, 663 (76.5%) PgR positive, 223 (25.7%) HER2/neu-positive and 86 (9.9%) were triple negative (TN). 86 (7.3%) were lobular carcinomas, 83 (96.5%) of which were ER-positive, 76 (88.4%) PgR positive, 5 (6.6%) were HER2/neu-positive and 2 cases (2.3%) were TN.

232 (19.6%) cases represented other variants, 32 (13.8%) of which were TN.

The total number of TN was 120 (10.1%). The number of low ER (1-9%) cases was 33 (2.8%), low PgR (1-9%) was 99 (8.4%). The number of cases with low both ER and PgR status was 4 (0.3%). The number of triple positive cases was 131 (11.1%).

Conclusion: There is a significant change in the rates of ER/PgR between 2006 and 2018 (p= 0.0001 and 0.0043 respectively for the ductal and <0.001 for ER in lobular). There is also a substantial difference although not statistically significant in HER2 rates. The reasons behind this change are not known but we may hypothesize that improved IHC quality and the accumulated experience of pathologists in addition to adoption of a more westernized lifestyle by patients as possible contributors.

PS-02-034

Analysis of prescribed adjuvant therapy for early triple-positive breast cancer

M. Urezkova*, A. Artemyeva, T. Semiglazova, A. Kudaybergenova

*N.N.Petrov Center of oncology, Russia

Background & objectives: Adjuvant therapy - gold standard for BC therapy. It is based on the stage and the surrogate tumour subtype. For ВС with HR expression and HER2 overexpression (TPBC) the NCCN protocols recommend a combination of chemotherapy, hormone and targeted therapy.

Methods: The aim of our study was to investigate the regimens of adjuvant therapy for TPBC that were prescribed to patients at our centre from 2012 to 2020. We selected patients with TPBC who received treatment at our centre from 2012 to 2020 and did not receive neoadjuvant therapy. Postoperative therapy (HT, TT and CT) appointments were monitored.

Results: The sample included 60 patients: pT1bN0 6.6%, pT1bN+ 3.3%, pT1cN0 35%, pT1cN+ 13.3%, pT2N0 25%, pT2N+ 15%, pT3N2 1.6%. Nobody received TT in the pT1b group, in the pT1c group - 51.7%, in the pT2 group - 54.1%. HT in the pT1b group received 66.6% of patients, pT1c group - 58.6%, pT2 group - 62.5%. Chemotherapy in the pT1b group received 50% of patients, pT1c group - 65.5%, pT2 group - 66.6%. The pT3N2 patient received a TT+CT. 36.6% of patients received a full combination of therapy, 30% - two types of therapy, 25% received one type of therapy, 1 patient didn't receive AT, 4 patients have no data.

Conclusion: Regardless of the pT category and the presence/absence of metastases in the regional lymph nodes of the patient with TPBC in the adjuvant mode, there are different treatment regimens. In only one third of the cases the patients were prescribed a combination of chemotherapy, hormone therapy, and targeted therapy. The presence of both hormonal receptors and HER2 expression in such patients and possible cross-talk between the signalling pathways of these receptors complicates the choice of therapy in this group.

PS-02-035

Intra- and inter-observer agreement in fibroepithelial lesions diagnosed with core needle biopsies in the breast

A. Vergili*, S. Yigit, D. Etit, A. Akder Sari, B. Bolat Kucukzeybek, A. Yazici

*Izmir Katip Celebi University Ataturk Research and Training Hospital Department of Pathology, Turkey

Background & objectives: Fibroadenoma (FA) and phyllodes tumour (PT) create diagnostic difficulties with core needle biopsies (CNB). The aim of this study is to evaluate the accuracy of FA and PT diagnoses as well as inter and intraobserver variability in CNBs.

Methods: Sixty-one patients were included in the study. Five breast pathologists independently reviewed these in 3 rounds. Inter-observer κ statistics were assessed and they were interpreted as follows: Kappa(K) ≤ 0 as indicating no agreement and 0.01–0.20 as none to slight, 0.21–0.40 as fair, 0.41– 0.60 as moderate, 0.61–0.80 as substantial, and 0.81–1.00 as almost perfect agreement.

Results: There was fair agreement between the pathologists with a κ value of 0.21 in round 1, and 0.28 in round 3. But there was none to slight agreement in round 2 (K =0.20). In the first round, the researchers were given only the age of the patients, while in the second round no information was given. The K values of stromal fragmentation, stromal cellularity, mitosis and atypia which were evaluated in the 3rd round were K = 0.73, 0.51, 0.47, and 0.40, respectively in the order of interobserver agreement. While intraobserver agreement was fair (K= 0.37, 0.37, 0.31) in 3 investigators, intraobserver agreement was moderate (K= 0.44,0.46) in 2 investigators.

Conclusion: The intraobserver agreement of the diagnosis of FEL in CNBs was found to be fair. To be able to diagnose FA and PT accurately there are no definite criteria however when the age, the defined histological criteria are given the agreement increases. The excisional biopsy is still gold standard in the diagnosis of FA and PT.

PS-03 | Cardiovascular Pathology Posters

PS-03-001

MMP9 expression and extracellular matrix remodelling in aortic diseases

B. Andrejic-Visnjic*, G. Samardzija, D. Tegeltija, B. Vukomanovic Djurdjevic, M. Djolai

*University of Novi Sad, Serbia

Background & objectives: Matrix metalloproteinases (MMPs) with roles in both physiological and pathological processes, are specialized for degrading various components of the extracellular matrix (ECM). Its synthesis and secretion may be affected by various endogenous or exogenous factors, including medications such as statins.

Methods: Aortic tissue of 40 patients with pathohistological diagnosis of dissection, mild and severe atherosclerosis, aortitis, mucoid degeneration and cystic medial necrosis was sampled. Tissue was stained with hematoxylin-eosin (HE) staining and immunohistochemically for MMP9. Epidemiological and clinically relevant data were obtained from patients records.

Results: Majority of patients were 60-69 years old, predominantly males. Most frequent diagnoses were atherosclerosis and dissection. MMP9 expression was noted rarely in mucoid degeneration and cystic medial necrosis, while number of cells were increasing in cases of mild atherosclerosis and aortitis, accompanied by mild to moderate ECM remodelling. Most abundant immunopositivity for MMP9 was observed in inflammatory cells in severe atherosclerosis and aortic dissection, followed by intensive extracellular matrix remodelling. In cases of severe atherosclerosis MMP9 expression was most prominent in macrophages in proximity of plaque. Application of statins in therapy, in most cases reduced MMP9 expression in atherosclerosis.

Conclusion: MMP9 expression in aortic diseases is a major contributor to ECM remodelling, while statins up to some point led to reduced MMP9 expression.

Funding: This manuscript was supported by the Ministry of Science and Technical Development of the Republic of Serbia (grant No 41012).

PS-03-002

Scanning electron microscopy in the diagnosis of complications of coronary artery stenting

V. Ubaydullaeva, B. Magrupov*

*Center for the development of professional skills of medical staff, Republican Research Center of Emergency Medicine, Uzbekistan

Background & objectives: Along with drug therapy and surgical treatment of coronary artery disease (CHD), interventional cardiology is actively being introduced into practice, where the most effective way is stenting of the affected segments of the coronary arteries.

Methods: A study of 45 stent coronary arteries (CA) with installed stents was carried out at various times (from one day to 3 years) in type 1 myocardial infarction (MI), using scanning electron microscopy (SEM).

Results: SEM helped to identify complications that developed during the installation of stents, and made it possible to see the processes of thrombus formation, as well as the formation of neointima. Thus, in 26.6%, type A dissection was observed, in 2% - CA perforation with the formation of pseudoaneurysm, in 8.2% - acute occlusion by a thrombus, in 4% - stent deformation.

Conclusion: Serial scans made it possible to determine the nature of the location of the stents in the affected areas of the coronary vessels. The magnification of the image of the object under study by several thousand times made it possible to objectively approach the issues of the quality of manufactured stents, possible damage during the installation of the latter into the lumen of coronary vessels, and the processes of thrombus formation on stents without medicinal coatings.

PS-03-003

Myocardium of children with congenital heart disease tetralogy of Fallot. Fibrosis, ploidy and ultrastructural features

N. Nizyaeva*, T. Sukhacheva, A.I. Kim, A.А. Burov, Y.L. Podurovskaya, R. Serov, L.A. Bockeria

*National Medical Research Center for Obstetrics, Gynaecology and Perinatology, Moscow, Russia

Background & objectives: The right ventricular (RV) myocardium of children with Tetralogy of Fallot (TF) undergoes hemodynamic overload immediately after birth, which results in significant morphological changes. This study aimed to investigate the myocardial morphology in children with TF and without cardiovascular pathology.

Methods: RV myocardium of patients with TF (n=51, 3-33 months) and without cardiovascular pathology (n=12, 1-36 months) were studied. Masson-trichrome and H&E-staining were used to assess the proportion of fibrosis and cardiomyocytes diameter. Cardiomyocyte ploidy was counted on DAPI-stained cell suspension obtained from paraffin-embedded tissue. Tissue fragments were also processed for electron microscopy. Significant correlations were revealed using nonparametric statistics.

Results: In TF children myocardial fibrosis didn’t differ significantly from the control (5,5±2,1% vs 5,8±3,2%), didn’t correlate with the age and cardiomyocyte diameters, but correlated with myofibrils assembly in cardiomyocytes. Fibrosis negatively correlated with low LVEF and O2 saturation. The cardiomyocyte diameter in TF children was significantly larger than in control (10,5±2,1μm vs 5,7±0,9μm) and correlated with the incidence of dyspnea-cyanotic attacks. The cardiomyocyte ploidy classes 2c:4c:8c:16c:32c in TF children was 22:49:24:4,5:0,5, in control - 71:2:6.2:0,8:0. In cardiomyocytes of TF children, ultrastructural signs of incomplete differentiation were revealed: foci of myofibril assembly, mitochondria, glycogen granules, centrioles in the sarcoplasm. The number of cardiomyocytes with areas without myofibrils decreased with age.

Conclusion: In RVOT myocardium of 1-2-year-old children with TF, fibrosis corresponded to age control, but increased with hemodynamic overload and hypoxemia. The diameter and ploidy of cardiomyocytes in children with TF exceeded the age norm, and the number of tetra- and octaploid cardiomyocytes was increased. Differentiation of cardiomyocytes with the assembly of myofibrils and other ultrastructural features was not only age-dependent but associated with hemodynamic parameters of the severity of congenital heart disease.

Funding: This study was supported by State Assignment №19-А21.

PS-03-004

Gender differences in changes in the structure of the media of the ascending aorta in patients with its dilatation and/or dissection

N. Nizyaeva*, T. Sukhacheva, A.А. Burov, E.V. Penyaeva, S.V. Garmanov, V.A. Mironenko, R. Serov

*National Medical Research Center for Obstetrics, Gynaecology and Perinatology, Moscow, Russia

Background & objectives: Dilation and/or dissection of ascending aorta in women and men can be caused by various reasons, including connective tissue dysplasia, and, accordingly, can have different morphological manifestations, the study of which is the purpose of this work.

Methods: Ascending aorta biopsies of 24 women (35-84 years) and 20 men (31-74 years) with aorta dilatation and/or dissection were examined. The thickness of aortic media was measured, Masson-trichrome, alcian blue and Weigert stain were used. The smooth muscle cells presence, fibrosis, cystic media degeneration (CMD) and elastic fibres were determined using a 4-point scale. The results were processed statistically.

Results: The diameter of ascending aorta in women was 57±10mm, in men 53±6mm. Aortic media thickness in women (374-1597μm) and men (798-1810μm) did not differ statistically. Aortic dissection was detected in 6/24 women and 4/20 men. In women aorta, CMD occurred significantly more often than in men (13/24 vs 3/20), it correlated with an increase in the aorta diameter. Smooth muscle cells loss and elastic fragmentation were identified. In men, aortic media petrification was revealed significantly more often than in women, (11/20 vs 3/24), an increase in the ascending aorta diameter correlated with elastic fragmentation. Aortic dissection in all patients was associated with smooth muscle cells loss, and media fibrosis.

Conclusion: The remodelling of the aorta with its borderline enlargement in women and men was due to different changes in the aortic media morphology, which were possibly hormone-dependent. In women, changes in the structure of aortic media were characterized by more frequent development of CMD and the accumulation of acidic glycosaminoglycans, in men - with petrification of the aortic media. Aortic dissection in patients of both genders was due to focal necrosis, smooth muscle cells loss, and media fibrosis.

Funding: This study is supported by State Assignment №19-А21.

PS-04 | Cytopathology Posters

PS-04-001

Endoscopic ultrasound-guided fine needle aspiration of intrapancreatic accessory spleen: a case series report and review of the literature

P. Gil Bernabe*, G. Silvestre Egea, C. Gonzalez Lois, M.R. Sánchez Yuste, J.L. Rodríguez Carrillo, M.d.C. Colomés Iess, J. Martín López

*Hospital Universitario, Spain

Background & objectives: Intrapancreatic accessory spleen is a benign congenital anomaly that can pose a diagnostic challenge, both clinically and in cytopathology. Clinical suspicion in the differential of a hypoechoic tail lesion should include this possibility but cytomorphologic features allows for the diagnosis.

Methods: From two intrapancreatic accessory spleen (AS) diagnosed in the last year in our department, we retrospectively review the literature regarding the differential diagnosis of hypoechoic pancreatic tail lesions and the main clinicopathological findings of AS. The clinical, endoscopic and cytomorphologic features are described with the immunohistochemical stains performed onto cell block material (CD3, CD20, CD8, CD56, Synaptophysin).

Results: Two female patients, aged 61 and 67 years old, were diagnosed of pancreatic AS in the last year. Both were evaluated by endoscopic ultrasound fine needle aspiration cytology (EUS-FNA) with rapid on-site evaluation (ROSE). The cytological smears revealed the presence of a hematic background on which a lymphoid population with small cell morphology predominated. Additionally, the presence of intermixed vascular tracts and some groups of habitual pancreatic acinar morphology were observed. Immunostaining of the cell block material confirmed the described cytology consisting of B lymphoid aggregates (CD20+) together with mature T lymphoid cells (CD3+) intermixed with vascular tracts lined by endothelial cells of the splenic sinusoidal type (CD8+).

Conclusion: The diagnosis of pancreatic AS by EUS-FNA is infrequent and the series describe a similar distribution based on sex and wide age range presentation. They are usually small lesions (between 0.8 and up to 3 cm) of the pancreatic body or tail and the clinical differential diagnosis include neuroendocrine or solid pseudopapillary neoplastic tumours. Some cases show cystic changes and development of epidermoid cysts. Cytology allows a specific diagnosis of the entity based on cytomorphological evaluation, avoiding unnecessary surgical interventions.

PS-04-002

Investigation of HPV-positive ASC-US shows in every third case squamous intraepithelial lesions – results of the German combined screening

G. Richter*, N. Santos, D. Teschner, A. Katzenstein

*Institut für Pathologie Dr. med. Georg Richter, MIAC, Germany

Background & objectives: 2020 the combined screening with HPV test and cytology for the early detection of cervical cancer was introduced in Germany. With a cytology finding of atypical squamous cells and a positive HPV test a diagnostic colposcopy should be carried out.

Methods: In 2020 total of 62557 Pap smears were cytological examined and HPV test was performed by using the HPV Aptima Test, which discriminated HPV 16, HPV 18/45 and other types (16,18,31,33,35,39,45,51,52,56,58,59,66,68). After diagnosis of atypical squamous cells of undetermined significance (ASC-US) and positive HPV test colposcopy in a specialized centre within 3 months were recommended.

Results: In 2352 women (3,8 %) ASC-US were diagnosed and in 1017 cases a HPV positivity was found. In 110 Cases (11 %) HPV 16 were detected, in 92 cases (9%) HPV 18/45 were detected and in 815 cases (80%) “other types” were detected. In 383 cases a colposcopy were performed and reported. In 272 cases (71 %) no essential lesion were detected and in 68 cases (18%) a low grade intraepithelial lesion (SIL) were diagnosed. In 43 cases (11%) a high grade SIL were diagnosed. No invasive cancer were found.

Conclusion: In the first year of the combined German screening we detected 1017 (1,6%) women with HPV positivity and atypical squamous cells of undetermined significance (ASC-US). After performing colposcopy 71 % of these women were inconspicuous and in 29 % intraepithelial neoplasia were detected. In 18 % LSIL and in 11 % HSIL were histological diagnosed. No invasive cancer was found. These data seems to be an expression of the importance of HPV positivity in ASC-US by detecting cervical lesions.

PS-04-003

Utility of Ki-67, p53 and PTEN biomarkers in endometrial carcinoma by imprint cytology

D. Riga*, I. Vamvakaris, E. Psychogiou, K. Kosmas, V. Michelis

*Pathology Department, General Hospital Of Thoracic Diseases “Sotiria”, Athens, Greece

Background & objectives: Worldwide, endometrial carcinoma is one of the most frequently diagnosed cancer among women and a considerable cause of death. Cytomorphology alone is not often sufficient to provide an accurate diagnosis, thus immunocytochemistry is required for aim assist.

Methods: Endometrial samples freshly resected from 168 women who underwent total abdominal hysterectomy were studied. The cytological diagnosis was confirmed by pathologists. Cytological imprint smears were obtained by touching the cut surface of fresh cancer tissues. The specimens were stained with Papanicolaou stain, Ki-67 (clone MIB-1, dilution 1:150), p53 (clone DO-7, dilution 1:50) and PTEN antibody (clone 6H2.1, dilution 1:80).

Results: Out of 168 cases, 123 were endometrioid and 45 non-endometrioid carcinomas. The rate of positive expression of Ki-67 (85.5%) and p53 (82.4%) was high in type II tumours (P<0.001), in cases of advanced and aggressive clinical stage and poor histologic differentiation and in cases with myometrial infiltration depth >1/2 (P<0.001). Also, high percentage of p53 (100%) positivity was found in all cases with positive lymph node involvement. High rate of positive expression of PTEN was observed in type I (43.4%) (P=0.910) and low-grade carcinomas (60.1%) (P=0.03), in unaffected by the disease lymph nodes (P<0.001) as well as in cases with myometrial infiltration depth <1/2 (P<0.001).

Conclusion: We believe that the use of Ki-67, p53 and PTEN antibodies in addition to cytomorphologic features, appeared to be useful for the diagnosis of endometrial carcinoma in endometrial cytology with imprint smears and may help identify tumours with high malignant potential and possible aggressive behaviour or ability to relapse offering valuable information, both in prognosis and treatment of patients with endometrial carcinoma.

PS-04-004

Role of endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of mediastinal disease in young patients

Y. Rodriguez*, T. Labiano Miravalles, M. Bronte Anaut, I. Morilla, S. Curi Chercoles, A. Martín Campos, A. Echegoyen, J. Elizalde Eguinoa, D. Guerro Setas, E. Almudevar

*Complejo Hospitalario de Navarra, Spain

Background & objectives: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) procedure is essential to diagnose diseases with mediastinal involvement. Cancer in younger patients comprises a distinct entity associated with poorer prognosis. This study aimed to review clinicopathological data in young patients who underwent EBUS-TBNA.

Methods: We retrospectively reviewed EBUS-TBNA results over two years (2019-2021) in patients aged under 55 years old. Rapid on-site evaluation (ROSE) was performed in all cases. Cytopathologists selected samples for ancillary studies. RT-PCR system (Therascreen/Idylla) was used for EGFR, ALK and ROS1; after May 2020, Next Generation Sequencing 52 gene-panel-based method was carried out (Oncomine Focus Assay, Thermo Fisher Scientific l).

Results: We studied 60 patients (38M/22F) aged 30-54. Of total, 61.7% showed negative for malignancy diagnosis; the reason for testing was a suspected diagnosis of sarcoidosis in 12 cases. One bronchogenic cyst was observed. In the remaining 23 cases (38.3%), 60.8% corresponded to NSCLC (86.6% adenocarcinoma, 1 poorly differentiated carcinoma and 1 squamous carcinoma). Molecular testing on adenocarcinoma cases was performed: 1 patient carrying EGFR deletion, another with BRAF mutation and 2 more patients with KRAS mutation and ALK fusion, respectively. 4.3% presented as small cell carcinoma and 8.7% as Hodgkin's lymphoma. In addition, 1 NUT carcinoma, 3 metastases of renal cell carcinoma and 2 of breast carcinoma were found.

Conclusion: EBUS-TBNA combined with ROSE has a high yield in the diagnosis of both neoplastic and non-neoplastic diseases with mediastinal involvement. In younger patients, the former may present with nonspecific symptoms and often have advanced disease at the time of diagnosis. Molecular testing in lung cancer is mandatory, especially in young patients. Rare subtypes of lung carcinoma should be included in the differential diagnosis.

PS-05 | Dermatopathology Posters

PS-05-001

Young pathologist’s nightmare: unexpected dermatopathology cases

B. Calim Gurbuz*, C. Caytemel, O. Erdem

*Basaksehir Cam and Sakura City Hospital, Turkey

Background & objectives: Dermatopathology encompasses a wide group of neoplastic/non-neoplastic lesions. Accurate pathologic diagnosis may be difficult especially for young pathologists, as there are numerous overlapping features. Our aim was to demonstrate some extraordinary situations that we often encounter in daily routine.

Methods: Five patients with unexpected pathologic diagnosis were retrieved between May 2020 and March 2021. The gender, age, site/characteristics of the lesions, preliminary diagnosis were collected from clinical data. After the first histopathologic evaluation, connection with the clinical diagnosis was established for all lesions. The second biopsies were taken from three of the patients for confirmation.

Results: Three of the five patients were female and the age distribution was between 6 and 64. The biopsy sites were lower extremity (three biopsies), back(one biopsy), scalp(one biopsy). Two of the patients were children and the preliminary diagnosis were traumatic panniculitis and vitiligo. The pathological diagnosis were granuloma annulare and mycosis fungoides, respectively. While two of the patients’ clinical diagnosis were basal cell carcinoma and necrobiosis lipoidica, the histomorphology was surprisingly compatible with lichen planus in both biopsies. The preliminary diagnosis of the other patient was squamous cell carcinoma. The biopsy demonstrated acantholytic disease with suprabasal clefting. The results of blood tests and immunofluorescence evaluation were also consistent with pemphigus vulgaris.

Conclusion: In the present case series, we evaluated the challenging spectrum of dermatopathology. Our cases suggested that the preliminary diagnosis is very important in skin lesions, but we should keep in mind the other possibilities. Clinical appearance sometimes can have overlapping features, and the experience of pathologist plays an important role in this situation. Therefore, the combination of good clinicopathologic communication and expert ideas is necessary in the management of challenging cases.

PS-05-002

Cutaneous metastases: a case series

Z.C. Olgun, G.E. Cecikoglu*, B. Cobanoglu Simsek

*Medeniyet University Prof. Dr. Suleyman Yalcin City Hospital Department of Pathology, Turkey

Background & objectives: Cutaneous metastases from a distant malignancy are a diagnostic challenge for pathologists. Secondary tumour deposits in the skin represent advanced malignancy and the skin is an uncommon site of metastatic disease when compared to other organs (0.5-2% through all malignancies).

Methods: The present study has analysed 41 cases of cutaneous metastases from internal malignant neoplasms. Patient characteristics, tumour localization, and clinical pre-diagnosis were evaluated.

Results: We evaluated 41 cutaneous metastases; the mean age of the patients was 62. Nine cases (23%) presented as primary manifestations of the tumour; biopsy evaluation in these cases suggested the possible primary tumour site and triggered further evaluation. The most common malignancy was breast carcinoma, and most common localization was anterior chest wall through all patients as well as for female patients. The most common malignancies were lung (n=5, 26%) and gastric carcinomas (n=5, 26%) for male patients, and the head and neck region was most common localization. In our cohort, 32 patients were clinically suspected of metastasis. However, 9 patients' clinical pre-diagnosis was primary skin malignancies without metastasis suspicion.

Conclusion: The classic presentation of cutaneous metastases was a firm, painless, flesh-coloured to an erythematous dermal nodule (or nodules). There is usually a long-time lag between the diagnosis of the primary malignancy and the recognition of the skin metastases. It is concluded that cutaneous metastases occur rarely and the presentation of internal malignancy with skin involvement is uncommon. Metastasis to the skin is often a pre-terminal event that heralds poor outcomes.

PS-05-003

Primary cutaneous gamma/delta T-cell lymphoma in Taiwan is more often solitary and not ugly-looking

S. Chuang*, B. Chen, R.C. Wang, J. Jhuang

*Chi-Mei Medical Center, Taiwan

Background & objectives: Primary cutaneous gamma/delta T-cell lymphoma (PCGD-TCL) is a very rare and aggressive. Patients usually present with multiple plaques, tumours, and/or subcutaneous nodules primarily distributed over the extremities. We present the clinicopathological findings of a small cohort of cases from Taiwan.

Methods: We investigated the clinicopathological features of PCGD-TCL cases with chart review, extensive immunohistochemistry for phenotyping including T-cell receptor (TCR) βF1, TCR-γ, and TCR-δ, in situ hybridization for EBV-encoded small RNA (EBER), treatment modality, and follow-up information.

Results: We identified six patients with a median age of 57. The lesions presented in the head and neck regions (n=3) and extremities (n=3). In five patients, the lesions were solitary, including two ulcerative. The tumour cells expressed CD3, CD8 (4/5), TIA-1 (5/6), granzyme B (5/6), TCR-γ (3/3), and TCR-δ (4/6). In two cases, the neoplastic cells expressed TCR-γ but not TCR-δ. Three cases partially expressed βF1. All negative for EBER. Four cases were at stage IE, and two at IIE. Excluding one recent case under chemotherapy, one died of lymphoma in 7 months, the remaining four were in complete remission after radiotherapy, either alone or with chemotherapy, in 6-126 months.

Conclusion: In this small series of cases from Taiwan, we found that five of the six PCGD-TCL cases presented with a solitary lesion, clinically mimicking lipoma or epidermal inclusion cyst in two cases. The clinical presentation is distinct from the ugly-looking, frequently necrotic, multiple tumorous lesions as reported in the literature. It is important to include PCGD-TCL in the differential diagnosis of solitary cutaneous TCL and perform extensive immunohistochemical study including cytotoxic markers and TCR.

PS-05-004

Pathological assessment of sentinel nodes in patients with cutaneous melanoma in Russian cancer research centre

D. Chuglova*, V. Kushnarev, G. Zinovev, M. Ebert, A. Artemyeva

*N.N. Petrov National Medical Research Center of Oncology, Russia

Background & objectives: Evaluation of sentinel lymph node (SLN) is crucial for cutaneous melanoma staging and treatment in patients with clinically negative lymph nodes. We evaluated SLN of patients who underwent SLN biopsy (SLNB) for skin melanoma between 2018 and 2021.

Methods: SLNB was performed in 303 patients, an average age of 53,7 years. Grossing of SLN depended on the size: those less than 5 mm were taken entirely, 5-10 mm were bevalved and those larger than 10 mm were grossed in bread loaf technique. After evaluation of the hematoxylin- and eosin-stained sections (9 cut levels per block), immunohistochemistry was performed.

Results: The stage distribution was following: pT1 - 65 (21,5%), pT2 - 98 (32,3%), pT3 - 74 (24,4%), pT4 - 58 (19,1%), in 6 cases stage was unknown (pitfalls of primary tumour grossing). The average Breslow index was 2,85 mm.

Metastasis was detected in 42 cases (13,7%), in 2 cases (4,8%) the excised tissue did not contain lymph nodes. Among all positive SLNs, metastases up to 2 mm were detected in 11 cases (26,2%) by immunohistochemistry (S100, SOX10 or Tyrosinasa).

Conclusion: Pathological assessment of the sentinel lymph node for malignant melanoma is extremely important, but the process is unstandardized yet.

PS-05-005

Male patient with a primary apocrine sweat gland carcinoma of the axilla: A case report of a rare entity

T.M. Costa*, D. Pinto

*Centro Hospitalar Lisboa Ocidental, Portugal

Background & objectives: Primary apocrine sweat gland carcinoma (PASGC) is a rare neoplasm with only 51 cases reported in the literature. It is often underrecognized, which can lead to undertreatment and enable disease progression.

Methods: A 74-year-old man with a recent history of adenocarcinoma of the lung, in remission for the past 6 years, presenting at our institution with a painless left axillary mass with 2cm, slowly growing for the past 3 years. On ultrasound examination, a diagnosis of epidermal keratinocytic cyst was suggested, and the patient remained on follow-up.

Results: As part of adenocarcinoma surveillance the patient was submitted to PET-CT, which showed the axillary mass was avid and suspicious for a metastatic neoplasm and was excised.

Macroscopic examination revealed a 2x2cm white nodule. Histologically, the tumour was well-circumscribed but infiltrative and centred in the dermis. Neoplastic cells showed an abundant, granular, eosinophilic cytoplasm, and large nuclei with prominent nucleoli. Immunohistochemically, they were positive for CK7, GCDFP-15, RA and negative for RE, RP, CK20, TTF-1, CDX2, P40 and PAX-8.

Based on these findings, a diagnosis of apocrine carcinoma was made. A full imagological workup of both breasts was performed, which found no suspicious masses/nodules, enabling a final diagnosis of PASGC.

Conclusion: PASGC are indolent but malignant tumours, with frequent local recurrence and lymph node metastasis. Due to their rarity, are often clinically misdiagnosed, leading to delayed therapy. Furthermore, a differential diagnosis with apocrine breast carcinoma cannot be made on immunohistochemistry or morphology alone, requiring a full imagological workup.

Surgical excision and lymph node dissection of clinically positive nodes are considered the treatment of choice. Further reporting and literature review are necessary to better understand the natural behaviour of this disease.

PS-05-006

The histopathological spectrum of inflammatory skin response to tattoo pigment

D. Costache*, A.M. Vrâncianu, R. Șoană

*Pathology Department, Colentina University Clinical Hospital, Bucharest, Romania

Background & objectives: With the rising popularity of skin tattoos, it is expected that the rate of adverse reactions will rise. As newer inks are utilized. This study will describe both the clinical and histopathologic features of pathologic reactions to decorative tattoos.

Methods: There are six main categories of histopathologic reactions: allergic hypersensitivity, granulomatous, interface, pseudolymphomatous, tumoral and infectious.

We present a series of six cases of tattooed skin biopsies from 3 male and 3 female patients with ages between 29-77 years old, with clinical diagnoses of psoriasis/lichen planus, pseudolymphomatous reaction to tattoo, acral melanoma/blue nevus, dermatofibroma/dermal nevus, eczema, foreign body granuloma.

Results: Microscopic examination revealed three cases of granulomatous reaction(a foreign body granuloma with multinucleated giant cells and two sarcoidal granulomas); a case of superficial perivascular lymphocytic dermatitis; a case of dermatofibroma(with a dermal proliferation of fibroblasts and histiocytes, with storiform pattern) and a case of pseudolymphomatous reaction.

Common skin reactions to tattoo include acute inflammatory reaction due to the trauma caused by needles with/without superficial or deep local infections, systemic infections, allergic contact dermatitis, photodermatitis, granulomatous, lichenoid reactions and skin diseases localized on the tattooed area (eczema, psoriasis, lichen, and morphea). We also have to consider the possibility of the development of cutaneous pseudolymphomatous reactions, pseudoepitheliomatous hyperplasia, or even cutaneous neoplasms.

Conclusion: Knowing and understanding the histopathological spectrum of skin reaction to tattoo pigment will increase clinical detection of situations requiring additional evaluation, whether it is for underlying infection, systemic involvement of disease, or to rule out a cutaneous malignancy. In suspect cases, especially papulonodular lesions arising in tattooed skin, early histopathologic diagnosis followed by excision of the lesion is important.

PS-05-007

Multinucleated cell angiohistiocytoma: a series of 15 cases

M.I. Craescu*, M. Frumosu, T. Tebeica

*Colentina Clinical Hospital, Romania

Background & objectives: Multinucleated cell angiohistiocytoma is a rare benign tumour with subtle histopathological features, making it an easy to miss diagnosis. The clinical appearance under the form of small red papules often leads to it being confused with an inflammatory disorder.

Methods: In this study, we reviewed a series of cases diagnosed over the course of 5 years (2017-2021) in one Dermatopathology unit. We examined the HE sections and clinical photos of 15 cases, aiming to identify common histopathological features that could aid in the diagnosis of this proliferation.

Results: MCAH is characterised by a histiocytic proliferation with multinucleated cells and dilated small blood vessels. In our cases, the histiocytic proliferation was distinct with frequent angulated and wavy cells, some with only a few scattered multinucleated cells present. There was a perivascular lymphocytic infiltrate, with half of our cases including frequent mastocytes. Thickened collagen bundles, randomly distributed in the upper dermis were also common. Less common histological features were represented by the presence of neutrophils, sebaceous and basaloid induction and also an exophytic, sessile architecture.

Clinically seven of our cases presented on the face and scalp, localisations not frequently reported in literature for this tumour.

Conclusion: Multinucleated cell angiohistyocitoma is a proliferation that does not have striking features and thus requires a more thorough examination. Most of the cases we examined were clinically suspected of being inflammatory disorders, such as lupus erythematosus, lichen planus, sarcoidosis or even lymphoproliferative disorders. For these reasons, we find that this is an important diagnostic to be aware of.

PS-05-008

Cutaneous metastases: a series of 74 cases

M.I. Craescu*, A.C. Lisievici, M. Frumosu, M. Leventer, G. Dodan, T. Tebeica

*Colentina Clinical Hospital, Romania

Background & objectives: Metastasis is the final stage in the evolution of malignant tumours and represents the main cause of cancer morbidity and mortality. Accurate histopathological diagnosis is urgent and essential for proper treatment.

Methods: This is a retrospective study including 74 cases diagnosed in our Pathology Department over a period of seven years (2015-2021). We thoroughly reviewed the HE slides, immunohistochemistry slides and the clinical information from the virtual database. Our aim was to observe histopathological features and make clinical correlations.

Results: Most cutaneous metastases were those of malignant melanomas (42%), followed by breast carcinoma (30%). The latter cases explain why most of the cutaneous metastases were diagnosed in women (68%).

Histopathologically, most of the cases did not present with ulceration (16%), epidermotropism (12%) or lympho-vascular invasion (19%). The typical clinical presentation was that of a nodule, with few cases of pigmented patches and dermatitis-like lesions.

The median age was 61 years, with one case of a 24-year-old without a prior history of melanoma.

Most of the cases presented on the trunk (44%), followed by head and neck (27%), extremities (14%), abdomen (11%), pelvis (4%).

Conclusion: Cutaneous metastases can be an important diagnosis to consider even in cases without clinical suggestion ( one third of our cases) or without former history of neoplasms (one fourth of our patients). Although most metastases retain the histopathological features of the primary tumours, some can have a deceivingly bland appearance. Metastases of lobular breast carcinoma can mimic inflammatory disorders such as granuloma annulare, morphea or lupus.

PS-05-009

A breast lesion on the nape?

M. Feltri*, A. Bonometti, S. Fraticelli, M. Lucioni

*Anatomic Pathology Unit, Department of Molecular Medicine, University of Pavia and Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy

Background & objectives: Endocrine mucin-producing sweat gland carcinoma (EMPSG) is a rare lesion, often underrecognized, mostly found in old women eyelid with heterogeneous growth pattern and considered the cutaneous analogue of solid papillary carcinoma of the breast.

Methods: We describe a case of a 75-years old woman complaining an asymptomatic skin coloured slightly raised lesion on the nape that underwent excisional biopsy. Gross examination revealed, in the dermis a seemingly cystic lesion of 0,6 cm of diameter. Specimen was processed according to routine procedure.

Results: Histological examination revealed, under a unremarkable epidermis, a cystic nodule composed of medium sized cells with round nuclei, sometimes prominent nucleoli, a discrete clear/eosinophilic cytoplasm and finely dispersed chromatin, organized in a predominant cribriform pattern and characterized by following immunohistochemical profile: EMA+, BerEp4+, CK7+/-, GCDFP15-/+, WT1-/+, CK20-, TTF1-, CEA-, Mammoglobin-, c-ErbB2-, positivity for oestrogen, progesterone receptors, and variable positivity for chromogranin, synaptophysin and androgen receptors. Moreover, PAS-Alcian stain revealed focal extracellular mucin deposits. Proliferation index assessed with Ki67 antibody, was low, about 5-10%. Provided the necessity to clinically exclude a metastasis, a diagnosis of Endocrine mucin-producing sweat gland carcinoma was made.

Conclusion: Only 22 EMPSG are described in literature, 50% initially misdiagnosed. Rare publications hypothesized the sequence carcinoma in situ-invasive carcinoma-mucinous carcinoma and parallelism with breast solid papillary carcinoma in situ-invasive solid papillary carcinoma-mucinous carcinoma, based on phenotypical and immunohistochemical similarities. Its outcome is favourable, with possible cutaneous recurrences and, because of its rarity, the molecular profile has not been studied yet. Therefore, investigating its molecular and chromosome abnormalities, could confirm breast-analogy and improve understanding the pathogenesis of both lesions.

PS-05-010

Cutaneous metastasis: a study of 58 cases diagnosed in our pathology unit

M. Frumosu*, L. Sticlaru, A. Dragusin, M.I. Craescu, A. Dinculescu, M.D. Petre

*Colentina Clinical Hospital, Romania

Background & objectives: Cutaneous metastasis can arise in a variety of cancers, not infrequently being the first sign of malignancy. Patients most commonly present with flesh-coloured nodules or plaque and only a part of them are suspected of metastasis.

Methods: We retrospectively reviewed the clinical records of 58cases diagnosed with cutaneous metastasis in our service during a twelve-years period(2009-2020). Our objective was to collect data and establish clinico-pathological correlations regarding cutaneous metastases diagnosed at Colentina-University-Hospital. We collected information from our database(sex, age, clinical presentation, suggestion of metastasis, presence of malignancy in the past) and methodically re-examined hematoxylin-eosin and immunohistochemistry slides.

Results: The age distribution was 34-89 years(mean 65), the majority of the patients were females(55,17%), 67,92% had clinical history of malignancy, only 18,87% of cases were sent as cutaneous metastasis.76,36% of cases were clinically described as single nodules, 9,43% as carcinoma erysipeloides and 3,76% as alopecia neoplastica. Trunk was frequently involved(23 cases), followed by head and neck(9 cases) and extremities(8 cases). Breast carcinoma(43,4%) and melanoma(22,64%) were the most common tumours to present with cutaneous metastasis, followed by gastro-intestinal carcinomas(20,75%) and prostatic adenocarcinoma(7,55%). The vast majority of the tumours weren't ulcerated and didn't present necrosis(84,91%).81,13% tumours were associated with a significant reactive inflammatory process, 32,08% presented vascular invasion and 11,32% perineural invasion.

Conclusion: In our study, most cases consisted of single nodules on the trunk at patients who already had a diagnosis of a malignancy, the most frequent being breast carcinoma and melanoma, as expected, accuracy of the clinical diagnostic increased when dealing with patients with known malignancies. It's important to further maintain a high level of suspicion when dealing with patients who already had been diagnosed with a form of malignancy in the past.

PS-05-011

Histopathological features of COVID-19 cutaneous lesions: a clinicopathological study of 5 patients

H. Gunel*, B. Cobanoglu Simsek, S. Ozkanli

*Istanbul Medeniyet University Prof. Dr. Suleyman Yalcin City Hospital Department of Pathology, Turkey

Background & objectives: With the increase of the coronavirus disease, more extensive data has shared about the dermatological findings of the disease. We aimed to describe histological features of cutaneous eruptions of the Covid 19 patients in our hospital.

Methods: We evaluated all skin biopsies which performed in hospitalized Covid-19 infected patients presenting concomitant cutaneous manifestations since March 2020. We reviewed 3 male and 2 female patients with a mean age of 24 years (range from 3-52). All patients had a nasopharyngeal swab positive for Covid-19 before the occurrence of rash.

Results: Clinically, all five patients presented maculopapular rash of the trunk and extremities. The latency between rash and onset of extracutaneous Covid-19 symptoms ranged from 3 to 30 days. Histologically, patients showed spongiotic dermatitis, basal vacuolar degeneration, red blood cell extravasations, endothelial hyperplasia, perivascular lymphocytic infiltrate, scarce neutrophils and eosinophils in a variable degree. Fibrinoid necrosis of the vessel walls was not found. Histopathological features of cutaneous manifestations reported in our study were unspecific.

Conclusion: Spongiosis and perivascular inflammatory infiltrate can be observed in various eruptions such as viral rash and drug reaction. Histopathological features of these two types of eruptions can also overlapping. Therefore, further studies are needed to clarify the relationship between cutaneous rash and Covid-19 virus.

PS-05-012

Study of the use of imiquimod for psoriasis model formation

M. Kostyaeva, A. Kosyreva, I. Kastyro*

*Peoples’ Friendship University of Russia, Russia

Background & objectives: In connection with a significant decrease in the quality of life of patients suffering from psoriasis, it became necessary to study the formation of a psoriasis model to study the possibilities of therapy choosing.

Aims: to develop psoriasoform skin lesions in rats.

Methods: 20 female Wistar rats were used. A psoriasis model was formed by applying a 10% solution of imiquimod to the back for 10 minutes once a day. 5 rats made up the control group (1gr). In 2nd group the solution of imichimod was used for 1day, in 3rd group-3days, in 4th group-5days. Histological preparations were stained with hematoxylin&eosin.

Results: In 2gr, 2 animals showed an increase in cellularity in the dermis, mild hyperaemia in the papillary layer of the dermis, and no pathomorphological changes were found on the side of the epidermis. In 3gr, the following changes in the epidermis were revealed in 3animals: in one case-acanthosis, in two animals-a scab with the formation of intraepidermal polymorphic cell proliferation. 4 animals in the dermis had polymorphic cell infiltrates, diapedesic haemorrhages, oedema and hyperaemia. In 4gr, 4 rats showed changes in the epidermis and in the dermis. Acanthosis, spongiosis, and the formation of epidermal pustules with exudate containing inflammatory cells were observed. In 2cases in 4gr,epidermal exfoliation, erosions, pustules & plaques was revealed.

Conclusion: The application of a 10% solution of imiquimod induces changes in rats similar to those in the dermis and epidermis in human psoriasis. Thus, changes in the skin after using a 10% solution of imiquimod in rats can serve as a model for psoriasis.

PS-05-013

The impact of hyaluronic acid and trehalosa on histological parameters of the skin

E. Kazachkov*, T. Zayats, G. Sychugov, Y. Kudrevich, O. Ziganshin

*South Ural State Medical University, Russia

Background & objectives: To study the morphological effects of the skin biorevitalization to improve its quality and rejuvenation before and after exposure.

Methods: The study involved 20 women aged 51. Biorevitalization was carried out by using a single injection of hyaluronic acid and trehalose under local anaesthesia. The skin was taken by punch biopsy before and 6 weeks after face injection. Slides were stained with hematoxylin and eosin and Masson's trichrome.

Results: The average thickness of the epidermis was 70.21±3.38 μm before the procedure and 85.13±7.01 μm after 6 weeks (p=0.05). The average thickness of the papillary and reticular layer of the dermis was 97.62±7.98 μm and 667.88±48.16 μm before the procedure, respectively. After the procedure, thickness decreased by 30% (p<0.05) and amounted to 68,95±5.03 μm and 468.67±43.53 μm. Decreased dermis thickness occurred due to decreased tissue oedema. In Masson's stained samples, the bulk density of collagen fibres was 65.6±7.0% before the procedure and increased to 74.4±5.8% after the procedure (p<0.01).

Conclusion: Hyaluronic acid and trehalose injections show significant changes that include epidermis thickening, induration of the dermis, and decreased tissue oedema.

PS-05-014

H Syndrome, a rare autosomal recessive genodermatosis, a case presentation

A. Al-Jawad, F. Al-Jaralla, H. Al-Hamami, F. Kubba*

*Ealing Hospital, London North West University Healthcare NHS Trust, Middlesex, United Kingdom

Background & objectives: This is a rare autosomal recessive genodermatosis with possible severe multisystem involvement. Its major cutaneous signs are hyperpigmentation, induration, and hypertrichosis. The cutaneous manifestations are very important as they are a pathognomonic clue for the diagnosis of this multisystemic syndrome.

Methods: A 13-year-old child presented with asymptomatic brown patches and hypertrichosis over his legs, inner thighs and the back, which appeared during infancy, associated with hearing loss since birth. He was diagnosed with insulin-dependent diabetes mellitus at the age of 7.

There was parental consanguinity and history of death of his sister from a cardiac problem and similar skin findings.

Results: On examination, the child was short for his age. He had indurated and hyperpigmented patches over the thighs, legs and the lower back with hypertrichosis and enlarged ambiguous genitalia. No hallux valgus was noted.

Abdominal examination revealed splenomegaly, but no hepatomegaly or lymphadenopathy was present.

Abdominal ultrasonography confirmed splenomegaly and echocardiography showed a pericardial mass.

Genetic study was not performed as it was not available to confirm the SLC29A3 gene on the long arm of chromosome 10 (10q22).

Histopathological examination of the involved skin showed mild acanthosis, increased melanin deposition in the basal keratinocytes, and nonspecific perivascular lymphocytic infiltrate in the superficial and mid dermis with mild dermal fibrosis.

Conclusion: We presented a case of H syndrome, a rare autosomal recessive genodermatosis.

Our diagnosis was based on the clinical and family history, clinical examination and investigations including a skin punch biopsy, and the patient was referred for the paediatrics department for further management and follow up.

It is important to recognize this syndrome which presents with a wide clinical variability and not to miss the characteristic skin findings which in most cases are good clues to the diagnosis.

PS-05-015

Lichenplanopilaris and telogen effluvium associated with severe dysaethesia and a lipedematous scalp, a case report of alopecia with multiple aetiological factors

F. Kubba*, A. Anton, M. Shetty, P. Dassan, F. Teixeira

*Ealing Hospital, London North West University Healthcare NHS Trust, Middlesex, United Kingdom

Background & objectives: A 47-year-old female who presented with a two-month history of diffuse scalp swelling which started after otitis media, associated with constant pain radiating to the face. Later she developed two patches of hair thinning in the vertex and occiput.

Methods: Clinical examination revealed a boggy and extremely tender scalp without erythema. There was reduced pin prick over V1 and V2 nerves. Other cranial nerves were normal on examination. CT scan and MRI of the head revealed thickened scalp fat up to 13.7mm.

Vitamin D, iron, zinc and thyroid levels were normal. Antinuclear antibodies(ANA) were borderline elevated. She had no anaemia.

Results: On microscopy, horizontal sections of the 4mm punch biopsy of the thinned vertex hair patch showed mild folliculocentric lymphocytic infiltrate with mild lamellar perifollicular fibrosis at the infundibulum, in keeping with lichen planopilaris (scarring alopecia), supported by the borderline elevated ANA levels.

Horizontal sections of the occipital hair loss patch biopsy showed seven telogen hair follicles without fibrosis or inflammation, supportive of telogen effluvium (nonscarring alopecia).

She was treated with gabapentin 400mg tablets TDS, greater occipital nerve block to control pain and topical betamethasone for alopecia.

One case of lichen planopilaris with androgenetic alopecia has been reported but such triple aetiology combination with lipedematous alopecia has not been described before.

Conclusion: We report a case of scarring alopecia; lichen planopilaris, associated with a nonscarring alopecia; telogen effulvium, in a background of severe hyperasthesia and lipedematous scalp, requiring gabapentin and nerve block to control the severe pain.

Hair loss due to multiple aetiological factors is reported, but not in a similar setting.

It is possible that severe occipital neuralgia together with the lipedematous scalp may have resulted in nonscarring alopecia.

A good clinicopathological correlation when reporting similar cases is very essential.

PS-05-016

Alopecia areata: is the recruitment of plasmacytoid dendritic cells time dependent? An immunohistochemical study

E. Kyrmanidou*, T. Koletsa, E. Lazaridou, E. Sotiriou, D. Ioannides, C. Fotiadou, S. Chatzopoulos, Z. Apalla, P. Hytiroglou

*2nd Department of Dermatology and Venereology, Aristotle University of Thessaloniki, Greece

Background & objectives: The expression of type 1 interferon-related proteins in alopecia areata (AA) lesions has been demonstrated and since plasmacytoid dendritic cells (pDCs) are premium producers of type I IFN their presence in acute, intermediate and chronic AA lesions was investigated.

Methods: Forty biopsy specimens, from a corresponding number of patients with AA lesions, were collected Twelve (30%) of them were categorized into acute, eleven (27.5%) into intermediate and 17 (42.5%) into chronic stage of the disease, according to the duration of the lesions. Immunohistochemical analysis with CD4, CD8, FOXP3 and CD123 antibodies was performed in formalin-fixed, paraffin-embedded tissue sections.

Results: The lymphocytic infiltration was perifollicular, and in 37.5% of the cases an intrafollicular distribution was identified, as well. Heterogeneity in lymphocytic density and distribution was present among hair follicles of the same specimen. CD123+ cells were identified in 33.3% of the cases in a perifollicular distribution. Their presence was associated with the chronologically determined stages of the disease (p=0.022) more often observed in the intermediate stage of AA, followed by the acute stage. Furthermore, an association of CD123+ cells and FOXP3+ cells in the immune infiltrate surrounding the hair follicle was found (p=0.013). No statistically significant association between CD123+ cells and CD4+ or CD8+ cells or their ratio was found.

Conclusion: This study suggests a role of pDCs in the pathogenesis of AA and a possible contribution in the initiation and in the early stages of the disease, but not in maintaining the chronic process. Coexistence and association of regulatory T cells and pDCs in a subset of AA lesions may reflect the biology of an impaired immune microenvironment.

PS-05-017

Audit of melanoma sentinel lymph node protocol pre- and post- updated EORTC protocol at a tertiary centre

S.H. Lee*, S. Edwards

*The Royal Marsden Hospital, London, United Kingdom

Background & objectives: The sentinel lymph node is an important prognostic marker in melanoma but approaches to pathological handling are varied. This study compares the positive detection rate and workload between the previous local protocol at Ninewells Hospital and updated EORTC protocol.

Methods: The records of 58 consecutive patients with primary cutaneous melanoma who underwent sentinel lymph node (SLN) biopsy at Ninewells Hospital and Medical School in East Scotland between 01/09/2017-01/11/2020 were reviewed. A positive detection rate of metastasis in SLN biopsy and the number of slides generated per case were compared between the previous local protocol and the updated EORTC protocol.

Results: SLN protocol was performed on a total of 108 sentinel lymph nodes (previous protocol n=45, new protocol n=63). With use of the previous local protocol, 8.89% of sentinel lymph nodes (4/45) demonstrated metastatic melanoma deposit. With implementation of the updated EORTC protocol, 12.69% of sentinel lymph nodes (8/63) showed metastatic deposit. The new protocol is associated with a higher detection rate (+3.81%) but this was not significant (Chi squared p=0.53). However, the average number of slides generated in the old protocol was 38 slides per lymph node but just 11 slides per lymph node on the new protocol (p= <0.001, Welch’s t-test).

Conclusion: The new EORTC protocol is proven to be non-inferior in detection of positive nodes but generates significantly fewer slides than the previous local protocol. The findings add evidence to support the use of the updated EORTC protocol for evaluating SLN. Studies with greater power would clarify whether the new protocol also has increased sensitivity to nodal disease.

PS-05-018

The characteristics of primary cutaneous melanomas associated with sentinel lymph nodes metastases

B.R. Nataras*, A. Dema, A. Plopeanu, S. Taban

*Department of Pathology, Emergency Clinical County Hospital Timisoara, Romania

Background & objectives: The purpose of this study was to evaluate the clinical and histological features of the primary cutaneous melanomas associated with sentinel lymph node metastases.

Methods: From the database of our pathology department, we selected the cases diagnosed as primary cutaneous melanomas, followed by sentinel lymph nodes excision from 2018 to 2020. We evaluated 26 cases with positive sentinel lymph nodes and 31 cases with negative sentinel lymph nodes.

Results: The first group included 14 females and 12 males (median age: 63,1 years). For the second group (20 females and 11 males), the median age was 55 years (p=0.0162). In the group with positive sentinel lymph nodes we noticed more often the nodular subtype (50%; p=0.0145), a Breslow index >4 mm (69,2%; p<0.001), ≥5 mitosis/mm2 (65,4%; p=0.0126), ulceration (77%; p=0.0275), lymphovascular invasion (19,2%; p=0.0106), satelites (27%; p=0.0103) and pT4 stage (69%; p<0.001). In the second group: superficial spreading type, vertical growth phase (67.7%), Breslow index >4 mm (13%), ≥5 mitosis/mm2 (32,3%), ulceration (48,5%), satelites (only 3,2%), early stages (61,2%), lymphovascular invasion absent. In both groups, the Clark level IV predominated.

Conclusion: In our study, the most important factors that can predict metastases in sentinel lymph nodes are the Breslow index and the pathological stage. The clinicopathological characteristics that affect the outcome of the patients are an advanced age at diagnosis, satelitosis, lymphovascular invasion, mitotic rate, the nodular subtype, and ulceration.

PS-05-019

A 1-year retrospective study of PD-L1 and CD8 expressions in malignant melanoma in South-eastern Romania

A.A. Nicolau*, B. Caraban, M. Aschie, E. Gheorghe, T. Hangan, O. Cojocaru, M. Deacu, G.I. Baltatescu, L. Petcu, G.C. Cozaru, M. Cristian

*Pathology Clinical Service of Constanta "St. Andrew" Clinical Emergency County Constanta, Romania

Background & objectives: Anti-programmed cell death protein 1(PD-1) therapy markedly improves prognosis in patients with the most aggressive tumours - melanomas. Our study is ongoing to better understand the role of PD-L1 as an immune-oncology marker, in combination with other prognostic features.

Methods: Retrospective evaluation of 31 cases of melanoma performed at our hospital in Constanta between 2018 to 2019. Data retrieved included clinical history and histological features such as Breslow tumour thickness, Clark level of invasion, greater dimension, pTNM stage, inflammatory infiltrate, lymphovascular and perineural invasion, number of mitoses. Histological and immunohistochemical studies (PD-L1 and CD8 ) were followed by statistical analysis.

Results: Of 31 cases, 57% were females, 43% were males, with anatomical sites such as posterior thorax 40%, followed by head and neck 23% of cases and less frequent in other sites. Between the four histologic types of melanoma encountered in our study we established some statistically significant differences of PD-L1 expression specially between invasive superficial spreading melanoma with vertical growth nodule/nodular melanoma and acral melanoma /in situ melanoma. The Breslow tumour thickness is the only reliable and recognized prognostic feature in melanoma, showing in this study a general negative correlation with the PD-L1 expression, with a rising percentage of negative expression cases in melanomas with higher values of Breslow.

Conclusion: An integrated analysis of both PD-L1, CD8 and TIL’s are be useful elements for predicting prognosis in patients with melanoma. Our findings suggest that there is a high variation of PD-L1 expression in melanoma, depending on the morphology, but further studies are needed in a larger cohort of melanoma patients, in order to validate a predictive value of the immunohistochemical PD-L1 expression.

Funding: This reasearch was supported by “Ovidius” University of Constanţa through the grant no. 6/14.11.2018

PS-05-020

The intricate aspects of diagnosing a nevoid malignant micromelanoma: a case report

D. Nicolcea*, D. Szilagyi, L.M. Marghidanu

*Department of Pathology, Emergency County Hospital "Pius Brinzeu", Timisoara, Romania

Background & objectives: Micromelanomas, having a diameter under 5 mm, are a new topic of interest in dermatopathology, raising awareness around early detection of this potentially fatal cancer. A nevoid micromelanoma poses a triple threat, considering its benign-looking features, rarity and small size.

Methods: This study reports a 34-year old Caucasian female, who presented to the hospital with multiple cutaneous lesions, four on her right upper arm and two on her right lower leg. Examination reveals the lesions were varying in size (from 4 mm to 7 mm) and macroscopic appearance (some nodular, some polypoid and one white plaque, with a grey halo).

Results: On histopathological examination, the results were as follows: three of the lesions were compound nevi, two were intradermal nevi, one of which was associated with a basal cell carcinoma with multiple risk factors, and the white, 4 mm, plaque was diagnosed as MELTUMP. A second opinion was requested and the lesion was ruled out as a nevoid malignant melanoma (Breslow index 0.8 mm, pT1b). To support the diagnosis, immunohistochemical analysis was performed, which showed melanocytic proliferation positive for S100 and MelanA, mitoses present, diffuse positivity for HMB45, indicating absence of cell maturation, Ki67 proliferating index of 5%, CD 45 positivity for chronic inflammation and CD 34 not supporting vascular invasion.

Conclusion: This particular case emphasizes the attention that should be given to benign-appearing nevi, especially those under 5 mm, in view of the fact that micromelanomas can be easily disregarded as benign, because of their low advancement in evolution and small size. In order to achieve early diagnosis of skin neoplasms, the entire arsenal at the pathologist's disposal should be used, as it can help improve the patient's diagnosis and prognosis.

PS-05-021

Clinical and histopathological features of nodular melanoma: a retrospective study from a Romanian tertiary centre

A.M. Pop*, A.C. Tinca, O.S. Cotoi

*George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Târgu Mureș, Romania

Background & objectives: Nodular melanoma (NM) is the most invasive melanoma subtype, often diagnosed in advanced stages, which causes a consistent proportion of deaths related to melanoma. This study aimed to identify the clinicopathologic features of NM diagnosed in a Romanian tertiary centre.

Methods: A retrospective study was conducted on all cases of NM diagnosed between 2017-2020 in the Department of Pathology of the Mureș County Clinical Hospital. The following variables were recorded: demographic data, tumour localization, Breslow thickness, Clark level of invasion, mitotic rate, presence of ulceration, tumour-infiltrating lymphocytes (TILs) and regression.

Results: The study group included 34 patients with NM (18 females and 16 males), with a mean age of 65.9±17.2 years. The most frequent tumour site was the trunk (47.1%), followed by the limbs (35.3%). Most of the tumours had a Breslow thickness >4.0 mm (55.9%) and a Clark level of IV (64.7%). The mean mitotic rate was 7.2±5.1 mitoses/mm2 (range 1-22) and there was a significant positive moderate correlation between mitotic rate and Breslow thickness, with Spearman correlation coefficient r=0.43 (0.098-0.677), p=0.01. Ulceration was present in 25 cases (73.5%). Most tumours presented brisk TILs (41.2%). Regression was observed in 2 cases (5.9%) and one NM was associated with nevus (2.9%).

Conclusion: The aggressive phenotype of NM is confirmed by the high Breslow thickness, frequent ulceration, increased mitotic rate and low association with regression and nevus remnants. Therefore, NM should be regarded as a de novo malignancy with high metastatic potential and delayed diagnosis.

PS-05-022

Immunohistochemical expression of matrix-metallo-proteinases in melanocytic nevi with intravascular protrusions and intravascular nevus cell aggregates compared to common melanocytic nevi

O. Stefan*, G. Tudor, M. Cioplea, A. Cioroianu, C. Caruntu, D. Boda, L. Cristina, A. Toma, A. Savin, S.A. Zurac

*Colentina Clinical Hospital, Romania

Background & objectives: Matrix-metallo-proteinases play a significant role in the progression of melanocytic lesions. The aim of this study is to evaluate MMP expression in common melanocytic nevi (CMN) with intravascular protrusions (IVNP) and intravascular nevus cell aggregates (IVNcA).

Methods: We performed a case control study including 30 CMN with IVNP and IVNcA and 30 paired CMN without IVNP and IVNcA and stained them for MMP-2, MMP-3, MMP-9, MMP-11 and MMP-13. Two investigators utilizing a modified Sinicrope's method scored the uptake of immunostains. Data was analysed using a paired Student's t test. The level of significance was set at p<0.05.

Results: We found that MMP-2, MMP-3, and MMP-11 were overexpressed in melanocytic nevi with IVNP and IVNcA compared to CMN (p = 0.004, 0.004 and 0.002, respectively). Interestingly, MMP-9 was overexpressed in common melanocytic nevi without intravascular protrusions and aggregates (p = 0.002). There was no statistically significant difference in the expression of MMP-13 in both study groups (p = 0.2691).

Conclusion: Our findings demonstrate that the majority of the analysed MMPs are differentially expressed in melanocytic nevi with intravascular protrusions and aggregates compared to CMN. This suggests that MMP-2, MMP-3 and MMP-11 play an important role in the pathogenesis of benign melanocytic lymph node deposits.

Funding: This work was supported by a grant of Romanian-Ministry-of-Research-and-Innovation, CCCDI-UEFISCDI, project number 61PCCDI/2018PN-III-P1-1.2-PCCDI-2017-0341.

PS-05-023

Tissue inhibitors of matrix-metallo-proteinases variation in melanocytic nevi with intravascular protrusions and/or aggregates versus common melanocytic nevi

G. Tudor*, O. Stefan, L. Nichita, C. Popp, V. Chitu, C. Salavastru, L. Cristina, R. Ardeleanu, M. Filip, D. Raduta, S.A. Zurac

*Colentina Clinical Hospital, Romania

Background & objectives: We evaluated TIMPs expression as players in tumour progression in common melanocytic nevi (CMN) versus CMN with intravascular protrusions (IVNP) and intravascular nevus cell aggregates (IVNcA).

Methods: Our study (case control type) includes 60 cases of CMN, half of them with IVNP and IVNcA; TIMP-1, TIMP-2 and TIMP-3 expressions were investigated. All cases were seen by two investigators; a modified Sinicrope's score was used. Data was analysed using a paired Student's t test for a level of significance of p<0.05.

Results: TIMP-1 was overexpressed in CMN nevi without IVPN and IVNcA (p = 0.002). TIMP-3 has a tendency towards overexpression in CMN with IVNP and IVNcA (p = 0.0106). No statistically significant difference in the expression of TIMP-2 in both study groups (p = 0.8249) was present.

Conclusion: TIMP-3 is overexpressed in CMN with IVNP and IVNcA compared with CMN without IVNP and IVNcA, TIMP-1 has the opposite manifestation while TIMP-2 has no significant variation; the importance of this differences in the expression of TIMPs in the pathogenesis of vascular affinity of melanocytes needs further research.

Funding: This work was supported by a grant of Romanian-Ministry-of-Research-and-Innovation, CCCDI-UEFISCDI, project number 61PCCDI/2018PN-III-P1-1.2-PCCDI-2017-0341.

PS-05-024

Association between histopathological findings and the diagnosis of cutaneous leishmaniasis, confirmed by PCR, in an endemic region of the Brazilian countryside: a cross-sectional study

J.C. Xavier*, H. Paulino Pena, V. Silva Belo, R. Gonçalves Teixeira Neto, T. Johnston Leitão, E. Sérgio da Silva

*Unisalesiano, Brazil

Background & objectives: Leishmaniasis presents itself from small skin lesions to visceral disorders that can evolve to death. To evaluate the association of histopathological criteria with the results of polymerase chain reaction (PCR) of clinically suspected cases of cutaneous leishmaniasis (CL).

Methods: An observational, cross-sectional, and retrospective study that evaluated, by PCR and histological examination, skin samples received during 9 years of clinically suspected cases of CL.

Results: The data showed full agreement between histopathological results and PCR when amastigote structures were identified. Moreover, the evaluated histological variables did not show statistical significance with the result of the PCR when considered individually: ulceration (P = 0.231), epidermal hyperplasia (P = 0.595), hyperkeratosis (P = 0.103), presence of granuloma (P = 0.280), neutrophils (P = 0.475), histiocytes (P = 0.241), lymphocytes (0.543), plasmocytes (0.291), and necrosis (0.746).

Conclusion: The data from the present study highlight the high specificity of microscopy analysis with 100% agreement with the PCR result for clinically suspected cases in an endemic Brazilian region. However, a histopathological finding in isolation cannot predict PCR positive results.

PS-06 | Digestive Diseases Pathology - GI Posters

PS-06-001

Mast cell quantification in chronic dextran sulphate sodium induced colitis animal model of inflammatory bowel disease

M. Antolic*, A. Ognjenović, H. Brzica, M. Dominis Kramarić, I. Glojnarić, S. Čužić

*Fidelta Ltd., Croatia

Background & objectives: Mast cell participate in inflammatory bowel disease pathogenesis by releasing various inflammatory mediators. Dextran sulphate sodium induced colitis in laboratory animals is commonly used IBD model. The aim of the study is mast cells quantification in chronic mouse/rat DSS model.

Methods: Animals were exposed to DSS in drinking water in three cycles of five-day duration. FFPE tissue sections were toluidine blue and PAS stained. Disease activity was evaluated using score (Int Pharmacol (2009) 9:1444). Mast cell number and percentage of degranulated mast cells was evaluated by digital image analysis (Calopix software, TRIBVN, France). Statistical evaluation was performed using GraphPadPrism software.

Results: Disease activity score was significantly higher in DSS groups of mice and rats in comparison to negative control groups.

In murine naïve and DSS-treated mice colon toluidine-stained mast cells were present in peri-intestinal fat tissue, mainly situated near vessels. In DSS-treated animals, number of mast cells slightly increased, while percentage of degranulated mast cells was not statistically higher than in naïve mice.

In rat naïve colon toluidine-stained mast cells were found in submucosa and peri-intestinal fat tissue. In distal colon of naïve rats most mast cells were degranulated. Percentage of degranulated mast cells in proximal colon submucosa significantly increased in DSS group compared to naïve animals.

Conclusion: In this study differences in mast cell number, distribution and degranulation status in naïve colon and DSS-colitis between mice and rats were highlighted. Also, most of the mast cells in naïve and DSS-colitis groups were degranulated (activated) in distal colon part.

PS-06-002

The impact of COVID-19 on colorectal cancer patients: where we are and what have we done?

R. Barna*, A. Beloia, M. Cornianu, S. Taban, E.G. Olteanu, A.D. Plopeanu, A. Muresan, S. Bogdan, B.R. Nataras, A. Dema

*Department of Internal Medicine II - Discipline of Gastroenterology and Hepatology, Victor Babes University of Medicine and Pharmacy Timisoara, Romania

Background & objectives: The new coronavirus disease 2019 (COVID-19) is an ongoing pandemic, generating an unprecedented health crisis, especially among patients with colorectal cancer (CRC). To better manage the evolving crisis, a state of emergency was declared in Romania on March 16, 2020.

Methods: The state of emergency had profound effects on oncology patients, particularly for CRC patients. Briefly, this study evaluated the impact of the COVID-19 pandemic on CRC patients in the largest hospital in western Romania. We performed a cross-sectional analysis on colorectal (CR) resection specimens received in our pathology department between March 16, 2018 and March 16, 2021.

Results: In 3 years of study data, 1035 CR resection specimens were examined: 733 were CR adenocarcinomas, 14 malignant CR tumours other than adenocarcinomas, 46 tumour recurrences, 28 specimens with direct invasion/metastases from other cancer and 214 were benign or non-neoplastic specimens. Only CR adenocarcinomas were selected, analysing the distribution and clinico-morphological features over 3 time periods: March 16, 2018-15 March 2019, March 16, 2019-15 March 2020 and March 16, 2020-16 March 2021. A slight decrease in the number of specimens was noted in the last year of the pandemic compared to previous years with two exceptions: March 2020, before the announced lockdown and June 2020, after the lockdown ended.

Conclusion: A difference was noted regarding the surgical treatment when between 2018-2020 elective surgeries were more frequent, while between 2020-2021 emergency interventions were more frequent. Finally, regarding CRC and COVID-19 pathological overlap, 6 patients had COVID-19 before hospitalization, 2 were infected at the time of surgery and 7 presented nosocomial infection. No specific histological findings were identified.

In conclusion, the impact of COVID-19 on the management of CRC patients was noticed in our hospital, but the overall impact was minor.

PS-06-003

Secondary appendiceal tumours: clinico-pathological spectrum of 20 cases in a 30-year single centre retrospective study

C. Cerezo*, Y. Rodriguez, M. Bronte, C. Fuertes, G. Aisa, M.C. Llanos, A. Panizo

*Complejo Hospitalario de Navarra, Spain

Background & objectives: Secondary appendiceal tumours (SATs) is an uncommon entity. It often causes acute appendicitis. In this study, we report the clinical and histopathologic features of secondary neoplasms involving the appendix.

Methods: We performed a single-centre, retrospective study of patients with confirmed SATs over a 30-year period of time. Direct extension of neoplasms originating in organs in proximity were excluded. The following parameters were recorded: patient clinical history, the appendiceal wall involvement, primary tumour site, and histologic type.

Results: The study consisted of 20 cases. The median age was 65 years.14 presented acute abdomen/appendicitis at diagnosis. Primary sites were gastrointestinal (n=6, 3 gastric signet-ring; 3 rectal adenocarcinomas), gynaecological (n=3, 1 ovarian clear cell carcinoma, 1 endometrial carcinoma; 1 leiomyosarcoma), pancreas-biliary tree (n=3), genitourinary (n=2, 1 urothelial carcinoma; 1 seminoma), lung (n=1 small cell carcinoma), breast (n=1), mesothelioma (n=1), and 3 adenocarcinomas of unknown origin. The wall involvement was: subserosa only (n=7), subserosa-muscle layer (n=7), subserosa-submucosa (n=3) and subserosa- mucosa (n=3). 13 SATs were synchronous and 5 were metachronous. Follow-up was available in all patients: 16 died of disease (median:2,5 months), 2 were free of disease and 2 in progression.

Conclusion: Although appendiceal metastasis are rare, it often results in acute abdomen-appendicitis. Familiarity and awareness of SATs is vital for accurate pathological diagnosis. The most frequent primary site in or series is the gastrointestinal tract. The SATs were usually associated with widespread disease and poor prognosis.

PS-06-004

Anti-apoptotic markers - role in personalized surveillance of patients with chronic gastritis and extensive intestinal metaplasia

A. Cernat-Ștefan*, C. Socoliuc, C. Dumitru, T. Voiosu, R. Ardeleanu, M. Maria-Alexandra, S.M. Sabo, D. Raduta, C. Popp

*Colentina University Hospital, Romania

Background & objectives: Gastric intestinal metaplasia (IM) is a precancerous lesion, metaplastic areas expressing an impaired balance between apoptosis and proliferation. We aimed to investigate anti-apoptotic activity in areas of IM, trying to identify patients with higher risk of evolution towards malignancy.

Methods: Immunostaining for bcl-2, Ki67 and MUC4 was performed on 20 biopsies showing chronic gastritis with extensive IM, separated in two groups: 10 cases Helicobacter pylori positive (HP+) and 10 cases Helicobacter pylori negative (HP-). Bcl-2 and MUC4 positivity in metaplastic epithelium were scored as 0/1+/2+/3+/4+. Ki67 expression was quantified as the percentage of positive tumour nuclei.

Results: Analysing comparatively the two groups, HP+ cases had a higher degree of severity of gastritis (average score 2.4 compared to 0.6) and more important glandular atrophy (average score 0.4 compared to 0). The mean score of bcl-2 and MUC4 positivity in the metaplastic epithelium was more important in the HP+ group (1.3 versus 0.9 for bcl-2 and 1.6 versus 1.2 for MUC4, respectively). In the HP+ group, Ki67 expression in metaplastic epithelium was significantly higher than in HP- group. Practically, HP+ group had a high proliferation rate associated with a high anti-apoptotic activity.

Conclusion: The alteration of the balance between apoptosis and cell proliferation is crucial in the development of gastric cancer; following the dynamics of anti-apoptotic markers in gastritis with intestinal metaplasia we can ensure a good surveillance of patients at high risk for dysplasia and gastric cancer.

PS-06-005

Association of IL-10 -1082A/G polymorphism with colorectal cancer risk

F. Mahdi, S. Dhouioui*, I. Zemni, A. Mezlini, H. Ouzari, N. Boujelbene, I. Zidi

*Laboratory Microorganismes and Active Biomolecules, Sciences Faculty of Tunis, University Tunis El Manar, Tunisia

Background & objectives: Tumoral microenvironment can count many kinds of growth factors and cytokines including IL-10. Substantial evidence recognizes IL-10 as an anti-inflammatory cytokine. We aimed to evaluate the involvement of IL-10-1082A/G polymorphism in the occurrence of colorectal cancer (CRC) in a Tunisian population.

Methods: Forty-nine patients (males 67% and females 33%, Mean age=60 years) with CRC, matched by sex with eighty healthy controls (males 66% and females 34%, Mean age=58 years) were genotyped for the cited polymorphism using the refractory mutation amplification system (ARMS-PCR).

Results: The genotypic distribution of AG genotype was increased in patients (69%) compared to controls (49%) suggesting its linkage to CRC risk (p=0.022; OR=2.383; IC 95% [1.126- 5.041]). Gender stratification demonstrated the association of IL-10 -1082A/G polymorphism only in males (p=0.05, OR=2.417, IC 95% [0.979-5.966]). Stratifications according disease stage and metastases do not show significant differences between allele/genotype distribution in patients vs controls.

Conclusion: Although preliminary, our data demonstrated that IL-10 -1082A/G polymorphism was related to CRC susceptibility in overall population as well as for males.

PS-06-006

A study of HLA-G 14pb Ins/Del gene polymorphisms profiling in colorectal cancer among females

S. Dhouioui*, N. Boujelbene, I. Zemni, H. Ouzari, A. Mezlini, I. Zidi

*Laboratory Microorganismes and Active Biomolecules, Sciences Faculty of Tunis, University Tunis El Manar, Tunisia

Background & objectives: Some studies have focused on the involvement of HLA-G gene, mainly the 3’untranslated (3’UTR) region, in colorectal cancer(CRC) susceptibility. We aimed at exploring whether HLA-G 14pb Insertion/Deletion (Ins/Del) could affect the occurrence or the progression of colorectal cancer in Tunisian females.

Methods: Forty female patients diagnosed with colorectal cancer at the Salah Azaiz Institute in Tunis (mean age= 54.65 years) and fifty-four healthy donors (mean age: 55.36 years). Genotyping of HLA-G 14pb Ins/Del was performed by conventional PCR.

Results: Comparison of the distribution of alleles and genotypes of polymophism14pb Ins/Del of the HLA-G gene showed that patients with Del allele (61% vs. 52%; p=0.199, OR= 1.467, 95% CI: [0.815-2.640]) and homozygous genotype Del/Del (43% vs. 24%; p=0.058, OR= 2.331, 95% CI: [0.962-5.645]) are more likely to be associated with colorectal cancer risk. There was neither correlation with demographic parameters nor with prognostic parameters (stage, grade).

Conclusion: In summary, HLA-G gene appears to be crucially involved in the genetic predisposition to colorectal cancer in Tunisian population. Further studies with larger cohort are needed to consolidate these preliminary findings.

PS-06-007

Clinicopathological features and prognostic factors in resected gastric cancer: a 19-year experience in a single tertiary centre

C. Díaz Del Arco*, L. Ortega Medina, L. Estrada Muñoz, A. Sánchez Pernaute, S. García Gómez de las Heras, M.J. Fernández Aceñero

*Hospital Clínico San Carlos; Universidad Complutense de Madrid, Spain

Background & objectives: In western countries, gastric cancer (GC) is diagnosed at advanced stages. Several prognostic factors apart from the TNM system have been reported. Our aim is to describe the outcomes and prognosticators of all patients with GC resected at our institution.

Methods: Retrospective study of all cases of GC surgically resected in a tertiary hospital from 2000 to 2019 (N=377). Clinical features were collected, histological features were independently assessed by two pathologists and statistical analyses were performed. Patients who received neoadjuvant therapy, metastatic tumours at diagnosis and patients with R1/R2 resections were excluded from the study. 315 patients were finally included.

Results: Tumours were intestinal (61%), diffuse (30.8%) and mixed (9.9%), according to Laurén’s classification. Necrosis, vascular invasion, perineural infiltration, infiltrative pattern, high grade tumours, signet-ring cells and budding were observed in 22.1%, 37.3%, 37%, 64.3%, 50.2%, 32.8% and 22.4% of cases. Most tumours were T3 (49.2%), N+(59.6%). During follow-up, 36.7% of tumours recurred and 27.4% of patients died due to GC. Recurrence was significantly related to patient age, tumour size, presence of signet-ring cells, Laurén subtype, tumour grade, perineural infiltration, vascular invasion, T and N stage. Tumour death was significantly associated with presence of signet ring cells, Laurén subtype, tumour grade, necrosis, infiltrative pattern, vascular invasion, desmoplasia, T and N stage.

Conclusion: Most GC cases were diagnosed in elderly (mean: 72 years) and symptomatic (89.9%) patients, and GC was detected at advanced stages. Apart from the TNM stage, several histological features were correlated with patient outcomes, including the identification of signet-ring cells, perineural infiltration, vascular invasion, Laurén classification, tumour grade, presence of necrosis and desmoplasia. The assessment of histological features is cost-effective, easy to perform, and it may improve the prognostic stratification of GC patients.

PS-06-008

Predicting outcome in resected gastric cancer: development of lymph node ratio-based prognostic scores for progression and survival

C. Díaz Del Arco*, L. Ortega Medina, L. Estrada Muñoz, A. Sánchez Pernaute, S. García Gómez de las Heras, M.J. Fernández Aceñero

*Hospital Clínico San Carlos; Universidad Complutense de Madrid, Spain

Background & objectives: The TNM staging system is the main prognostic tool in gastric cancer (GC). Lymph-node ratio (LNR) is a recently studied feature which could improve patient stratification. Our objective is to develop LNR-based prognostic scores for patients with resected GC.

Methods: Retrospective study of all cases of GC surgically resected in a tertiary hospital from 2000 to 2019 (N=377). 315 cases were included. Clinicopathological features were collected and univariate and multivariate analyses were performed. Prognostic scores for predicting tumour death and recurrence were constructed based on hazard ratios (HRs). Their prognostic role was analysed by receiver-operating characteristic (ROC) and Kaplan-Meier analyses.

Results: Most tumours were T3 (49.2%) N+ (59.6%), and mean LNR was 0.2. The recurrence score included LNR, T stage and Laurén subtypes, and classified our patients into 5 groups (S1-S5). Kaplan-Meier curves for disease-free survival (DFS) showed an excellent prognostic stratification, and p value (log-rank test) was <0.001. The score for tumour death included LNR and T stage. Kaplan-Meier curves for overall survival (OS) showed and excellent stratification into 5 prognostic groups (p <0.001). Mean OS for S1-S5 cases were 172, 140, 116, 84 and 22 months, respectively. The AUC values for recurrence and tumour death were 0.722 and 0.763. Both scores were independently related to OS and DFS.

Conclusion: Lymph node staging is a controversial issue in GC, and several alternative lymph node classifications have been proposed. According to previous studies, LNR may reflect the extent of lymph node dissection and overcome the limitations of the N stage. In our study, LNR-based prognostic scores showed good prognostic performance in GC patients. Thus, LNR-based scores may be helpful for patient stratification in GC, and they may serve as an alternative or an adjunct to the traditional TNM classification.

PS-06-009

Prognostic role of the log odds of positive lymph nodes in western patients with resected gastric cancer: a comparison with the 8th TNM staging system

C. Díaz Del Arco*, L. Ortega Medina, L. Estrada Muñoz, A. Sánchez Pernaute, S. García Gómez de las Heras, M.J. Fernández Aceñero

*Hospital Clínico San Carlos; Universidad Complutense de Madrid, Spain

Background & objectives: Several alternative lymph node (LN) staging systems have been recently described in gastric cancer (GC). The log odds of positive LNs (LODDS) is calculated as “log [(positive LNs+0.5)/(negative LNs+0.5)]”. We aim to evaluate the prognostic role of LODDS in GC.

Methods: Retrospective study of all cases of GC surgically resected in a tertiary hospital from 2000 to 2019 (N=377). Clinicopathological features were collected, LODDS was calculated and statistical analyses were performed. 315 patients were finally included. LODDS was categorized into 5 groups (S1-S5) for survival analysis. Cases were classified as S1 (25.6%), S2 (18.4%), S3 (21.3%), S4 (20.3%) and S5 (14.4%).

Results: The LODDS classification was significantly associated with tumour size, Laurén subtype, presence of signet-ring cells, tumour grade, perineural infiltration, lymphovascular invasion, growth pattern, tumour recurrence and death. Kaplan-Meier analysis of disease-free survival (DFS) according to the LODDS classification produced distinct, non-overlapping curves (p<0.001). Kaplan-Meier analysis of overall survival (OS) showed good patient stratification (p<0.001), but S1-S2 curves overlapped after 60 months. N stage showed worse prognostic performance for both OS and DFS by Kaplan-Meier analyses. AUC values for recurrence and death were similar between the two classifications. LODDS classification was independently related to both OS and DFS.

Conclusion: Some investigators have suggested that LODDS may be superior to the TNM stage in GC. In our study, the LODDS-based classification showed better prognostic performance than the N stage, and it was an independent predictor of OS and DFS. Based on these findings, LODDS-based staging systems can be used at least as complementary methods to predict patient outcomes in GC. Further research should evaluate the role of LODDS classifications in GC, and efforts should be taken to standardize cut-off values.

PS-06-010

Development of a simplified log odds of positive lymph nodes-tumour staging system for western patients with resected gastric cancer

C. Díaz Del Arco*, L. Ortega Medina, L. Estrada Muñoz, A. Sánchez Pernaute, S. García Gómez de las Heras, M.J. Fernández Aceñero

*Hospital Clínico San Carlos; Universidad Complutense de Madrid, Spain

Background & objectives: The log odds of positive lymph nodes (LODDS) has been proposed as an alternative staging system for predicting patient outcomes in gastric cancer (GC). Our aim is to develop a simplified tumour-LODDS staging system for patients with resected GC.

Methods: Retrospective study of all cases of GC surgically resected in a tertiary hospital from 2000 to 2019 (N=377). Clinicopathological features were collected. Neoadjuvant, metastatic and R1/R2 cases were excluded, and 315 patients were finally included in the study. LODDS was calculated, and cases were categorized into 5 groups (L1-L5). A T-LODDS staging system was developed and statistical analyses were performed.

Results: GC cases were classified as L1 (25.6%), L2 (18.4%), L3 (21.3%), L4 (20.3%) and L5 (14.4%). The T-LODDS classification divided patients into 5 stages (S1-S5). Cases were S1 (8.3%), S2 (24.4%), S3 (17.5%), S4 (28.7%) and S5 (21.1%). The T-LODDS system was significantly associated with systemic symptoms, tumour size, depth, macroscopical type (Borrmann classification), Laurén subtype, presence of signet ring cells, tumour grade, lymphovascular invasion, perineural infiltration, infiltrative growth, tumour recurrence and death due to tumour. Kaplan-Meier curves for overall survival (OS) and disease-free survival (DFS) showed distinct non-overlapping curves, and p value according to log-rank test was <0.001. T-LODDS classification was an independent predictor of both OS and DFS.

Conclusion: The simplified T-LODDS classification showed an excellent prognostic performance in our study, and it was an independent predictor of OS and DFS. Based on these results, the T-LODDS staging system can be useful for predicting prognosis of patients with resected GC, and it can at least complement the traditional TNM system. More studies should be performed in larger populations to validate its prognostic value.

PS-06-011

Prognostic value of a new staging system based on the location of metastatic lymph nodes in patients with gastric cancer

C. Díaz Del Arco*, L. Ortega Medina, L. Estrada Muñoz, A. Sánchez Pernaute, S. García Gómez de las Heras, M.J. Fernández Aceñero

*Hospital Clínico San Carlos; Universidad Complutense de Madrid, Spain

Background & objectives: In 2016, Choi et al. published a hybrid topographical and numerical lymph node (LN) staging system for gastric cancer (GC). Our objective is to develop a T-LN staging system based on the Choi classification for patients with resected GC.

Methods: Retrospective study of all cases of GC resected in a tertiary hospital from 2000 to 2019 (N=377). Clinicopathological features were collected. Neoadjuvant, metastatic and R1/R2 cases were excluded. 315 patients were included. Choi classification was applied, and tumours were classified as N0 (49%), N1 (22.9%), N2 (17.4%) and N3 (107%). A T-LN classification was constructed, and statistical analyses were performed.

Results: Patients were categorized into 6 groups according to the T-LN classification: S1 (15.9%), S2 (15.5%), S3 (19.9%), S4 (19.1%), S5 (25.1%) and S6 (4.4%). This classification was significantly related to systemic symptoms, tumour size, depth, Laurén classification, signet-ring cells, tumour grade, necrosis, perineural infiltration, lymphovascular invasion, recurrence and tumour death. Kaplan-Meier curves for OS showed good stratification into 6 prognostic groups (p<0.001). The TNM system showed poorer discriminatory ability (IA-IB, IIA-IIB and IIIB-IIIC curves overlapped). In respect of disease-free survival (DFS), both the TNM and T-LN systems showed good prognostic stratification. AUC values for recurrence and tumour death were similar. The T-LN classification was independently related to OS and DFS.

Conclusion: Previous research has shown that novel LN classifications based on the anatomical extent of the disease can successfully predict the prognosis of GC patients. In our study, a T-LN staging system based on the Choi classification showed slightly better prognostic performance than the TNM system. Thus, alternative T-LN classifications may help to overcome the limitations of the current TNM system. Further studies in larger populations should be performed to confirm the prognostic value of alternative staging systems in GC.

PS-06-012

Assessment of immunohistochemical expression of MMP9 and EGFR in colorectal carcinomas with tumour budding – immunohistochemical expression as prognosis tool and potential therapeutical target

M. Filip*, D. Raduta, E. Ignat, A. Dinculescu, R. Ardeleanu, O. Stefan, C. Socoliuc, A. Benguș, C. Popp

*Colentina Clinical Hospital, Romania

Background & objectives: Tumour budding (TB) is an adverse prognostic factor in colorectal carcinomas (CRC), involved in local invasion and distant metastasis.

The purpose of our study is evaluation of MMP9 and EGFR immunohistochemical expression in peritumoral budding (pTB) and intratumoral budding (iTB).

Methods: We conducted a retrospective, comparative study including 20 cases of colorectal adenocarcinomas (10 with pTB and 10 with iTB) recording the type, stage, grade of anaplasia and grade of TB. We analysed expression of MMP9 and EGFR in tumour, tumour budding and peritumoral stroma and we correlated the results with clinicopathological data.

Results: MMP9 showed strong positivity in tumour in 17 cases (8 with iTB, 9 with pTB), and in TB in 14 cases (8 with iTB, 6 with pTB); it was moderately positive in peritumoral stroma in 15 cases (10 with iTB, 5 with pTB). EGFR was positive in tumour in 7 cases (4 with iTB, 3 with pTB), in TB in 12 cases (5 with iTB, 7 with pTB), and in peritumoral stroma in 4 cases with pTB. EGFR expression was statistically significant higher in peritumoral stroma of tumours with pTB than of tumours with iTB. MMP9 expression in peri-budding stroma was stronger that in peritumoral stroma (p=0.0029, two tailed t-test)

Conclusion: MMP9, a gelatinase involved in degradation of extracellular matrix and of the basement membranes, two essential steps in tumour invasion and migration, is strongly positive in tumour cells and has and enhanced expression in stroma around TB areas. EGFR expression is high in tumour stroma, especially in tumours with pTB. As potential therapeutical targets and markers of poor prognosis, MMP9 and EGFR can be used in establishing sub-groups of CRC patients to include in clinical trials.

PS-06-013

Immunohistochemical expression of Silent information Regulator 2 Homologue1 (SIRT1) in colonic inflammation dysplasia carcinoma sequence

A. Hamdy*, D. Shehata Elazab, S. Saad Elkholy, M. Elkablawy, A. Gaber Abdou

*Menoufia University, National Liver Institute, Egypt

Background & objectives: Colorectal carcinoma (CRC) is the seventh most common lethal cancer in Egypt. SIRT1 as histone deacetylase has supposed protective role in colorectal inflammation and carcinogenesis.

To compare immunohistochemical expression of SIRT1 in control group, inflammatory bowel disease, adenoma and CRC.

Methods: This retrospective study was carried out on 78 cases, divided into four groups; 30 cases of CRC (colectomy specimens), 22 cases of adenoma, 15 cases of IBD and 11 cases of control group. Immunohistochemical expression of SIRT1 was evaluated by H-score in using microarray technique.

Results: SIRT1 showed nuclear staining in all cases of the control and IBD groups. Adenoma and CRC cases showed also SIRT1 expression in 95.5% and 77.4 % respectively. There was a significant progressive reduction of H-score values of SIRT1 from normal colonic specimens (Mean=185) compared to IBD (Mean=78), adenoma (Mean=84) and carcinoma (Mean=63). On the other hand, there was no statistical differences between adenoma and carcinoma groups regarding SIRT1 expression

Conclusion: SIRT1 has a protective suppressor role against intestinal inflammatory and neoplastic processes. Its defective expression is associated with promotion of inflammatory, dysplastic and carcinogenesis sequence.

PS-06-014

Prognostic significance of microsatellite instability in gastric adenocarcinoma

K. Hamza*, K. Bellil, M. Lakhal

*UR17ES17-faculté de médecine de tunis, université tunis el manar., Tunisia

Background & objectives: Gastric cancer (GC) is one of the most aggressive malignancies. Several associations between microsatellite instability (MSI) and other clinicopathological factors have been reported in GC. In this study we investigated the correlation between MSI and prognostic factors of GC.

Methods: The study included 37 patients with gastric adenocarcinoma. MSI deficiency was assessed by immunohistochemical analysis using MLH1, PMS2, MSH2 and MSH6 and confirmed by polymerase chain reaction (PCR) using a panel of five microsatellite markers specific for two mononucléotide loci (BAT25, BAT26) and three dinucleotide loci (D5S346,D17S250 and D2S123).

Results: Out of 37 total cases of gastric cancer, 29 (78,5%), 3 (8%), and 5 (13,5%) were microsatellite stable (MSS), low-level MSI (MSI-L), and high-level MSI (MSI-H), respectively. Compared to MSS/MSI-L, MSI-H gastric cancers were significantly associated with female gender ( P=0,021) and inflammatory stromal reaction (p=0,03). There was no statistically significant association between MSI-H and other selected clinical parameters: age, tumour location, who histotype, lymph node status, vascular invasion, perineural invasion and pTNM status.

The 5-year overall survival of patients with MSI-H tumours was 80% versus 44% for MSS/MSI-L tumours (p=0,37).

Conclusion: The MSI status should be incorporated in routine pathological report because it defines a different pathological entity with a better outcome. Also, by its correlation with inflammatory stromal reaction, it can be considered as a useful biomarker to identify patients who will respond to immune checkpoint blockade inhibitors.

PS-06-015

Clinicopathological characteristics of Epstein-Barr virus-associated gastric carcinoma in 108 Tunisian cohort

F. Sassi, R. Jouini, I. Helal*, F. Khanchel, D. Haddad, R. Hedhli, E. Ben Brahim, M. Sabbah, A. Chadli-Debbiche

*Habib Thameur's Hospital, Tunisia

Background & objectives: The Cancer Genome Atlas, in 2014, provided a new molecular classification defining EBV-associated-gastric carcinoma (EBVaGC) as a distinct subtype.

We analysed clinicopathological characteristics of EBVaGC.

Methods: One-hundred and eight gastric cancer patients treated by gastrectomy between 2001 and 2018 were enrolled. Clinical and pathological features were recorded from the database. All diagnoses were confirmed histologically. Tissue cores were sampled from the paraffin embedded tumours after marking the most representative tumour regions and prepared as tissue microarrays. EBER in-situ hybridization was performed by an automated method.

Results: The tumour was EBER-negative if staining was only expressed in benign lymphoid cells, and EBER-positive if the malignant epithelial cells showed a nuclear staining. There were 108 gastric cancer patients of which 62 were men. EBV positivity was present in 39 cases. EBVaGC was associated with age at diagnosis (45-84years;P =0.009).EBVaGC involved the proximal parts in 20 cases. EBV-positivity was most detected in poorly cohesive adenocarcinomas (53.8%;P=0.003). Seven cases were lympho-epithelial-like carcinomas. There was no correlation of EBER-positivity with the tumour stage or metastatic lymph nodes. Median as well as 1, 3, and 5-year survivals among EBER-positive tumours were shorter. The difference wasn’t shown to reach statistical significance (P = 0.19).

Conclusion: We found tumour EBV positivity more frequently in male than female gastric carcinomas patients, similar to several other studies. We also found higher EBV positivity in poorly cohesive adenocarcinoma in contrast to other studies who showed predominance of intestinal type. EBVaGC is a distinct subtype of gastric carcinoma with regard to its clinicopathological features. It must be diagnosed in every resected specimen as it can become a predictive biomarker for response to immune checkpoint inhibitors.

PS-06-016

Prognostic value of tumour-stroma ratio in colorectal carcinomas

A. Hmidi*, F. Khanchel, I. Helal, M. Ben Thayer, E. Ben Brahim, A. Chadli-Debbiche

*Habib Thameur Hospital, Tunisia

Background & objectives: Tumour-Stroma Ratio (TSR) is currently considered as a prognostic factor in several cancers. The objective of our study was to assess the prognostic value of TSR in colorectal carcinomas (CRC).

Methods: The study was retrospective in a period of one-year. We included all cases of CRC stade II and III, diagnosed in the Pathology department of Habib-Thameur Hospital, and for which tumour excision was performed. Tumours were classified into two groups: Tumours rich in stroma (TSR ≤50%) and tumours poor in stroma (TSR>50%), following a methodology widely used in the literature.

Results: A total of 33 cases of CRC were included (16 males and 17 females). The mean age was 61.8 years. The TSR value was between 10% and 80% with an average of 39%. The TSR was > 50% in 17 cases (51.5%) and ≤ 50% in 16 cases (48.5%). The overall survival was significantly reduced in cases of Tumours rich in stroma (p=0.005). We found a correlation between a TSR ≤50% and tumour size (p= 0.028). Correlations between TSR and lymph node status, tumour stage, and lymphovascular invasion were not statistically significant.

Conclusion: Our study demonstrated that a high stroma proportion or an exaggerated desmoplastic response would be associated with an unfavourable outcome in patients with CRC. TSR is an important prognostic and predictive factor for CRC. Its easy assessment and reliability allow it to be used in clinical practice, particularly to identify high-risk patients who can justify adjuvant chemotherapy.

PS-06-017

Gastric MALT lymphoma: a report of 42 cases in a Tunisian health care centre

A. Hmidi*, I. Helal, F. Khanchel, M. Ben Thayer, E. Ben Brahim, A. Chadli-Debbiche

*Habib Thameur Hospital, Tunisia

Background & objectives: Gastric MALT lymphoma (GML) is a rare pathology with a low potential for malignancy. However, this lymphoma can be easily under-diagnosed due to clinical and endoscopic polymorphism. Our study’s aim was to assess clinical, endoscopic, and anatomopathological features of GML.

Methods: This was a retrospective descriptive study that included all cases of GML, collected from the Pathology Department of Habib Thameur Hospital over a period of 23 years (from 1997 to 2020).

Results: We collected 42 cases of GML. These were 24 men and 18 women (sex ratio = 1.3). The mean age was 53.7 years. The disease was revealed in the majority of cases by abdominal pain. The endoscopic appearance was nonspecific, dominated by ulcerations (42%), an ulcerative tumour (18.4%), congestive gastropathy (15.8%), nodular gastropathy (10.5%) or rarely an infiltrated appearance. These lesions were in the antrum in the majority of cases. Helicobacter Pylori (HP) was present in 44.5%. HP status was uncertain in 14% of cases. The transformation of GML into large B cell lymphoma was noted in 24% of cases. Immunohistochemistry confirmed the B phenotype in all cases.

Conclusion: Inconsistent with our results, GML is more common in males. Its incidence increases significantly from the age of 40. It is a lymphoma with a low potential for malignancy. This lymphoma progresses slowly and may resolve completely after eradication of HP. Its transformation into LBDGC is possible and due to the accumulation of new genetic alterations, especially, involving the bcl6 and p53 genes. The immunological phenotype is CD20 +, CD79a +, CD5-, CD10-, CD23-, CD43-, bcl2 +.

PS-06-018

Isolated germline MSH6 mutation associated with Muir-Torre syndrome: a case report and review of the literature

A. Hogeboom Gimeno*, M. Camara Jurado, J.L. Rodriguez Peralto, R. Gallardo Gallego, M.C. Garrido Ruiz

*Hospital 12 de Octubre, Spain

Background & objectives: Muir-Torre syndrome (MTS) is a phenotypic variant of hereditary nonpolyposis colon cancer (HNPCC) associated with germline mutation in mismatch repair gene MSH2 ( 90%) or MLH1 (10%). We describe a rare case of MTS harbouring an isolated MSH6 mutation.

Methods: Clinicopathologic features including phenotypic, histologic and molecular characteristics of a recently diagnosed patient with MTS and isolated germline MSH6 mutation are described. A literature review is carried out identifying similar reported cases. Included cases meet criteria of MTS (visceral malignancy associated with sebaceous epithelioma, adenoma or carcinoma) while demonstrating an isolated MSH6 mutation upon germline mismatch repair gene analysis.

Results: A male with a history of multiple sebaceous neoplasms and colorectal carcinoma (CRC) at age 54 was found to have a germline point mutation in exon 4 of MSH6. Seven additional similar cases were identified in the literature making a total of eight cases meeting inclusion criteria: 7/8 cases (87%) were male and 6/8 cases (75%) developed CRC, with an average age of presentation of 58.8 years. 60% of CRC occurred in distal (rectosigmoid) colon. 5/8 cases (62%) developed extracolonic cancer. The majority of mutations involved exon 4 of the MSH6 gene.

Conclusion: Despite scarce data, preliminary characterisation of MSH6 mutation-associated MTS suggests a male predominance, a relatively older age of CRC presentation (58.8 years in our series versus 50 years, the median age of presentation of CRC previously reported in MTS) and high risk of both colonic (especially of the distal colon) and extracolonic malignancies. This peculiar phenotype may contribute to these patients frequently being missed when screening for HNPCC using Amsterdam criteria.

PS-06-019

Tumour-associated M2 macrophages in stage I-II gastric adenocarcinomas

A. Ieni*, R.A. Caruso, C. Pizzimenti, G. Giuffrè, G. Tuccari

*Department of Human Pathology in Adult and Developmental Age “Gaetano Barresi”, Section of Pathology, University of Messina, Italy

Background & objectives: Macrophages are cellular protagonists of tumour microenvironment in many tumours. In order to clarify the clinico-pathological significance of intratumoral macrophages, we have compared clinico-pathological features of two cohorts, analysing stage I-II gastric adenocarcinomas containing macrophages with pT- and stage-matched controls.

Methods: Twenty-four cases of stage I-II gastric adenocarcinomas with intra-glandular foamy macrophages were identified; their clinico-pathological features were firstly compared with 72 pT-matched as well as stage-matched control cases of adenocarcinomas with case-control ratio of 1:3. The immunohistochemical procedure against prediluted antibodies: CD68, CD 80 and CD163 on a Ventana BenchMark Ultra. Univariate and multivariate analysis have been applied.

Results: Macrophages showed immunoreactivity for CD68 and CD163 and were organized in mature granulomas. Immunohistochemical features were reminiscent of M(Hb) macrophages, a specific phenotype within M2 macrophages. In any case of our cohort, M1 macrophages was documented by CD 80 immunostaining. There were no significant differences in age, gender, tumour location, size, lymphovascular and perineural invasion between case group with M(Hb) macrophages and pT- as well as stage-matched controls; furthermore, case group showed lower frequency of lymph node metastasis (p=0.02). A significant different clinical course and overall survival rate were also observed in gastric adenocarcinomas with macrophages (p=0.02) in comparison to controls.

Conclusion: We suggest that tumour-associated M(Hb) macrophages are related with a quite indolent growth and a better prognosis of patients with this peculiar variant of gastric adenocarcinomas.

PS-06-020

Novel immunohistochemical markers for gastrointestinal stromal tumours with potential prognostic and therapeutical value

E. Ignat*, L. Nichita, E. Grămadă, D. Răduță, A. Dinculescu, M. Filip, B. Mastalier, C. Popp

*Colentina Clinical Hospital, Romania

Background & objectives: Gastrointestinal stromal tumours (GISTs) are the most frequent mesenchymal neoplasms of the digestive tract and are characterized by variable histopathological features and clinical outcomes. The aim of this study is to evaluate Her2 and p16 expression in GISTs.

Methods: We present a retrospective study including 16 cases of GISTs. Immunohistochemical analysis for c-kit, DOG1, CD34, Her2 and p16 was performed. For all specimens we registered location, morphology, mitotic count, tumour size and tumour risk (based on recent WHO guide: low risk - 1, 2, 3a, 3b; high risk - 4, 5, 6a, 6b).

Results: The stomach location demonstrated predominant spindle morphology (5/6 cases) and a smaller medium size (4.6 cm) compared to the colon (7 cm). Her2 positivity correlated with a higher risk (71.42% of high risk-GIST showed Her2 overexpression vs. 33.33% of low risk-GIST), but also with a mixt morphology and a gastric location. There was no relationship found between p16 expression and any of the histopathological features.

Conclusion: Our results suggest a strong correlation between Her2 overexpression and risk grade, tumour extension and mitotic index. Despite literature data, our research could not correlate p16 levels with any of the high-risk features. These interesting findings demonstrate the necessity for larger studies that can further characterize from a molecular point of view this peculiar type of stromal tumours. A better understanding of GISTs can lead to the discovery of new therapeutical options.

PS-06-021

Proximal gastrointestinal lesions in Crohn disease in paediatric patients – a single centre experience

R. Jankovic*, J. Jevtic, N. Ristic, I. Milovanovic

*Institute of Pathology, Faculty of Medicine, University of Belgrade, Serbia

Background & objectives: Precise diagnosis of Crohn disease (CD) in children and adolescents and lesion distribution are crucial for therapy choice in CD. The aim of study is to determine frequency of lesions in proximal segments of gastrointestinal tract in paediatric CD patients.

Methods: All biopsies taken at the University Children's Hospital, Belgrade over the 4-year period (2017-2019) were reviewed using histopathology reports from the files of the Institute of Pathology, Faculty of Medicine, University of Belgrade. Selected histological slides were re-examined.

Results: A total of 49 cases of CD were identified with similar frequency in both gender (M:F=1.04). The average age of patients was 14.5 ± 2.61 years. Median of symptoms duration before histopathological diagnoses of CD was 5 months (3 weeks - 5 years). One quarter of patients (13/49) had specific histopathological findings related to CD in proximal segments of gastrointestinal tract. Chronic granulomatous inflammation was found in the oesophagus (3), stomach (5) and duodenum (1). Focally enhanced gastritis was found in 10.2% of patients with CD of ileum and colon. More than half of patients with characteristic CD lesions (7/13) in proximal gastrointestinal tract had normal findings at proximal endoscopy.

Conclusion: A significant proportion of paediatric CD patients have proximal gastrointestinal lesions. Multiple biopsies are crucial for CD diagnosis in proximal gastrointestinal tract in children because poor endoscopic detection of characteristic lesions.

PS-06-022

Hepatoid adenocarcinoma of the gallbladder: a diagnostic pitfall with hepatocellular carcinoma

D. João*, A. Furtado, A. Sanches, L. Santos

*Department of Anatomic Pathology, Centro Hospitalar de Vila Nova de Gaia/Espinho, Porto, Portugal

Background & objectives: Hepatoid adenocarcinoma is a variant of adenocarcinoma with histopathological features that resemble hepatocellular carcinoma, its main differential diagnosis. It most commonly arises in the stomach and less frequently in the lung, kidney, pancreas and gallbladder, the latter being exceedingly rare.

Methods: We report the case of 59-year-old male followed in the infectious diseases department due to hepatitis C infection. An ultrasonography study revealed a polypoid lesion of the gallbladder, initially suspected as a metastasis of hepatocellular carcinoma. However, computed tomography and magnetic resonance imaging detected no lesions in the liver besides hepatic cirrhosis. The patient was then submitted to a cholecystectomy.

Results: Microscopically, a malignant epithelial neoplasm was found, with muscular layer invasion. The tumour was composed of cords and sheets of large polygonal cells with enlarged nuclei, evident nucleoli and abundant cytoplasm, resembling hepatocytes. There was neither lymphovascular nor perineural invasion and no hepatic tissue was identified. Immunostaining was diffusively positive for CAM5.2, Glipican-3 and AFP, with multifocal arginase positivity. No immunoreaction was found for CK7 and CK19. Thus, the patient was diagnosed with primary hepatoid adenocarcinoma of the gallbladder. The patient’s serum AFP values returned to normal range after the surgery. Only 15 other cases have been reported in English published literature during the last 20 years, which were reviewed.

Conclusion: This rare entity is thought to derive either from hepatic differentiation of conventional adenocarcinoma during tumour progression or from bipotential neoplastic cells that differentiate into cells with either hepatoid or glandular features. Hepatoid adenocarcinoma may or may not produce AFP and seems to have a more aggressive course than adenocarcinomas without hepatoid features, regardless of AFP production. Due to location and morphologic similarities to hepatocellular carcinoma it should be taken into account as a differential diagnosis, as treatment is distinct.

PS-06-023

Histological grading of mucinous colorectal carcinoma - an ongoing challenge

A. Jurescu*, A. Gheju, S. Tăban, M. Cornianu, A. Mureșan, C. Lăzureanu, R. Cornea, A. Văduva, O.C. Vita, A. Dema

*Department of Pathology, “Victor Babeș” University of Medicine and Pharmacy, Timișoara, Romania

Background & objectives: The pathological grading of mucinous carcinoma (MC) is still unreliable, with successive amendments in the 2000/2010/2019 WHO colorectal carcinoma (CRC) classifications. We aimed to investigate whether the histological grade based on glandular differentiation has prognostic significance in MC.

Methods: We performed a retrospective study on a group of 191 patients with MC who underwent surgery at the "Pius Brînzeu" County Emergency Hospital from Timișoara, Romania. All tumours were staged and graded according to the AJCC 2017 and WHO 2019 CRC classifications. In multivariable analyses, we assessed the associations between the histological grades and the other prognostic factors in CRC.

Results: Based on the degree of glandular differentiation, 17 cases (8.9%) were well differentiated (G1) MC, showing >95% glandular formation, 115 (60.2%) moderately differentiated (G2) - 50-95% glandular formation, and 59 cases (30.89%) poorly differentiated (G3) with glandular structures in <50% of the tumour. Regarding the associations of histological grade with the prognostic parameters, we observed positive correlations between MC grade and patients' age (p=0.0332), tumour extension - pT (p=0.059), lymph node status - pN (p=0.0168), lymphovascular invasion – LVI (p=0.0005) and tumour site – right colon/left colon/rectum (p=0.0477). All G3 MCs cases were diagnosed in the pT3-pT4 stage and the vast majority was associated with right side, pN+ and LVI+.

Conclusion: In our hands, the conventional classification based on the degree of glandular differentiation seems to have prognostic significance. Due to the ease of evaluation on usual stained slides, histological grade appears to be a promising prognostic factor in MC, but still requires establishing of the cut-offs between grade classes, therefore standardization of the assessment method and its validation in large prospective cohort studies.

PS-06-024

Clinicopathological analysis of prognostic factors in colorectal carcinoma: a large retrospective study

A. Jurescu*, A. Gheju, S. Tăban, M. Cornianu, A. Mureșan, C. Lăzureanu, R. Cornea, A. Văduva, O.C. Vita, I. Mihai, G.E. Olteanu, V. Lupu, A. Dema

*Department of Pathology, “Victor Babeș” University of Medicine and Pharmacy, Timișoara, Romania

Background & objectives: The tumour stage remains the strongest and most reliable prognostic factor in colorectal cancer (CRC). We evaluated the clinicopathological parameters in early vs. deeply invasive NOS adenocarcinomas, variables that could better predict the adverse outcome in patients with CRC.

Methods: We performed a ten-year retrospective study on 1612 patients with NOS adenocarcinomas who underwent surgical resections in Timișoara County Hospital. Associations between the pT parameter (pT1-pT2 vs. pT3-pT4) and the following prognostic factors: age, sex, tumour location, histological grade (G), lymph node status (pN), lymphovascular invasion (LVI) and distant metastasis were statistically analysed using Chi square/Fisher's exact test.

Results: Regarding the tumour extension in the intestinal wall, we observed 240 (15%) pT1-pT2 and 1372 (85%) pT3-pT4 adenocarcinomas. In terms of tumour differentiation: 107 adenocarcinomas were well differentiated (7%) (G1), 1280 (79%) moderately differentiated (G2), 207 (13%) poorly differentiated (G3) and 18 cases (1%) undifferentiated carcinomas (G4). From the category of pT1-pT2 tumours, only 2 cases (0.8%) were pM1, 42 (17.5%) pN+, 27 (11.25%) LVI and 105 tumours (43.75%) were diagnosed in the rectum. In the multivariate analysis, right localization (p<0.0001), poor differentiation (p = 0.0005), pN+ (p<0.0001), LVI+ (p<0.0001) and distant metastasis (p<0.0003) were significantly associated with the depth of tumour invasion.

Conclusion: In our study, we showed that clinicopathological parameters could provide solutions for risk stratification in patients with CRC. Although the analysis of certain molecular factors are useful and attractive from the perspective of prognostic significance for these patients, the risk of aggressive tumour behaviour in CRC with early invasion of the intestinal wall can be predicted easier and more cost-effective by evaluating histological parameters on HE stained slides.

PS-06-025

Clinicopathologic and prognostic differences between mucinous and non-mucinous adenocarcinoma

G. Kir*, H. Gunel, Z.C. Olgun, R.B. Girgin, I. Tosun, O. Alimoglu

*Istanbul Medeniyet University, Turkey

Background & objectives: Mucinous adenocarcinoma (MAC) is a histological subtype of colorectal cancer. The principal aim of this study was to evaluate whether the biological behaviour of MACs differs from that of non-mucinous adenocarcinoma (NMAC) in patients undergoing surgery for colorectal cancer.

Methods: The relationship between clinicopathologic parameters and tumour histology was investigated in 180 consecutive patients who underwent surgical resection for colorectal carcinoma.18 out of 180(10%) tumours were MAC,162 out of 180(90%) were NMAC. The patients’ clinicopathological parameters and follow-up and survival data were obtained. The log rank test was used for univariate survival analysis, and the multivariate Cox regression for overall survival (OS) and disease-free survival (DFS).

Results: On multivariate analysis, larger tumour size and lymph node involvement were more frequently observed in patients with MAC than NMAC (odds ratio (OR) = 10.411,95% confidence interval (CI)=2.436-44.498, p=0.002, OR=6.402, 95%CI=1. 380-29.696, p=0.018, respectively) The majority of the MAC were located on the right side (OR=7.539, 95%CI=1.575-36.074, p = 0.11). The median follow-up period was 46 months. We observed a statistically significant difference between MAC (81.3%) and NMAC (94.9%) for five-year DFS (OR=4.518,95%CI=1.130-18.072,p=0.033). We did not observe a statistically significant difference for five-year OS between MAC (72.2%) and NMAC (84.6%).The multivariate Cox proportional hazards model revealed that larger tumour size, older age and presence of lymphovascular invasion were significantly associated with decreased OS (OR= 2.070, 95%CI=0.991-4.321, p=0.053, OR =3.712 95CI =1.655-8.326, p=0.003 and OR=3.652, 95%CI=1.676-7.956, p=0.002, respectively).

Conclusion: Patients with MAC have worse outcomes compared to patients with NMAC. On multivariate analysis, mucinous histology was an independent predictor for DFS with an odds ratio of 4.518.

PS-06-026

Role of microvessels in predicting risk of distant metastasis in localised colorectal cancer

A. Konstantinov*, K. Shelekhova

*St. Petersburg Oncological Center, Russia

Background & objectives: Colorectal cancer can recur within five years as distant metastasis in about 25% of cases. Our study aimed to identify the role of microvascular density (MVD) and pericyte impaired microvessels (MPI) in the risk of metastasis.

Methods: We undertake a retrospective study of lymph node-negative colorectal cancer with synchronous distant metastases (n=53), metachronous metastasis (n=45), and without metastases (n=53). The mean follow-up was five years. Triple immunohistochemical staining was made: ERG, α-SMA, podoplanin. In the highest neovessel density area, individual microvessels are counted in an area 1.0 mm2. The index of microvessel immaturity MPI/MVD was calculated (Index-V).

Results: Normal blood vessels have shown ERG expression and α-SMA immunoreactivity anywhere around the vessel perimeter, whereas immature tumour microvessels lacked α-SMA immunoreactivity. The difference of MVD in groups was insignificant, mean 10/mm2 in non-metastasizing and 11/mm2 in metastasizing. Metastasizing tumours demonstrate significantly higher MPI (mean 8/mm2 versus 2/mm2) and higher Index-V (mean 0.69 versus 0.21). Both showed a significant correlation with distant metastasis (p<0.0001).

Conclusion: These findings demonstrate that immature neovascularization correlates with metastasis, resulting in a poorer prognosis. Taken together, not only microvessel density but also vascular maturation is crucial factors for colorectal cancer patients. The evaluation of tumour angiogenesis from the viewpoint of its maturation and its quantity helps predict the tumour's malignant potential.

PS-06-027

Interobserver agreement in classification of dysplasia in colorectal adenomas; a multicentre study

M. Konur*, B. Bolat Kucukzeybek, A. Avci, F.H. Dilek, F.S. Pehlivan, F. Dag, I. Aydin, I. Cakir, N. Ekinci, S. Karaarslan, A. Akder Sari

*Izmir Katip Celebi University Ataturk Training and Research Hospital Department of Pathology, Turkey

Background & objectives: Grading of dysplasia in colorectal adenomas (CRA) is important given the huge impact on post-polypectomy surveillance. Two-tiered grading system low-grade dysplasia (LGD) and high-grade dysplasia (HGD) is suggested and terms such as adenocarcinoma in-situ or intramucosal carcinoma are discouraged.

Methods: To assess the usage of current dysplasia grading guidelines in routine daily practice and the interobserver variability in CRAs, pathologists are provided by current detailed dysplasia grading guidelines. Six gastrointestinal, 3 routine pathologists independently evaluated 40 CRA-biopsies, first-as in their routine practice and after (min 30 days washout) current guidelines were provided. Inter-observer κ statistics was assessed using multi-rater Kappa.

Results: All observers preferred to use variable terminology including adenocarcinoma in-situ and/or intramucosal adenocarcinoma for HGD in routine practice; these cases are grouped as HGD for statistics. The interrater agreement was fair (K=0.371;95%CI 0.369-0.372) among all observers. However, it was higher among routine pathologists in comparison to GI pathologists; moderate (K=0,600;95%CI 0.594-0.606) versus fair (K=0,261; 95%CI 0.258-0.263) respectively. In the second review, interrater agreement increase to moderate among all observers (K=0,509;95%CI 0.508-0.511). The increase-rate was intense among GI-pathologists (K=0.523;95% CI 0.520-0.525) but was slight, reaching to substantial among routine pathologists (K=0,630;95%CI 0.624-0.635). The diagnostic rate of LGD increased by 1,1 to 10 times among GI pathologists in the second review.

Conclusion: Current dysplasia grading guidelines are not widely used even amongst in GI pathologists. Variable terminologies for HGD are still common in practice. Implementation of current guidelines to practice increases interobserver agreement and helps to avoid overdiagnose of LGD as HGD. Strategies should be developed to ensure the usage of current guidelines in routine practice.

PS-06-028

Incidence and clinicopathological features of mismatch repair deficient (MMR-d) colorectal carcinomas (CRC): a tertiary single-centre data from Turkey

M. Konur*, S. Demir, B. Bolat Kucukzeybek, I. Cakir, A. Akder Sari

*Izmir Katip Celebi University Ataturk Training and Research Hospital Department of Pathology, Turkey

Background & objectives: Mismatch repair immunohistochemistry (MMR-IHC) is a widely used method to detect microsatellite instability (MSI). Reflex testing to all newly diagnosed colorectal carcinomas (CRCs) is suggested. The study aims to investigate the incidence of MMR-d CRCs and clinicopathological features.

Methods: Consecutive CRC resections from a total of 455 patients in between March 2017- May 2020 were included in the study. The data were recorded from database including MMR-IHC results. Suboptimal stainings were reviewed and 24 patients were excluded for various reasons.

Results: MMR-d tumours constituted 10% (44/431) of all CRCs, the mean age of the patients among MMR-d tumours 63,14 (min34-max94); MMR-stable tumours 64,2 (min 30-max90). MMR-d and MMR-stable tumours female/male ratio was 21 (47,7%)/23 (52.3%); 165 (42.6%) /222 (57,3%) respectively.

The rate of MMR-deficiency among multiple CRC tumours was higher (25%) than unifocal tumours (10,7%). Right colon was the most common location in MMR-d tumours in comparison to MMR-intact tumours (72%, 30,6%). The rate of mucinous adenocarcinoma was also higher in MMR-d tumours 11,3% ( 5/44) than MMR-intact tumours 6,3% (25/395).

Among MMR-d tumours, 72,7% (n=32), 25% (n=11), %2,2 (n=1) showed MLH1&PMS2, MSH2&MSH6 and PMS2 deficiency respectively.

Conclusion: According to our single-centre data, the incidence and clinicopathological features of MMR-d tumours seem to be in line with the literature in Turkish population. It is noteworthy that multiple tumours tend to have a higher rate of MMR deficiency in comparison to unifocal tumours.

PS-06-029

Tumour infiltrating lymphocytes in microsatellite-unstable gastric adenocarcinoma

M. Lakhal*, K. Hamza, H. Azzouz, R. Latrach, B. Chelly, A. Zehani, I. Chelly, S. Haouet, K. Bellil

*UR17ES17, Medical School of Tunis, University Tunis El-Manar, Tunisia

Background & objectives: Microsatellite instability (MSI) is a major molecular subtype in gastric adenocarcinoma characterised by high lymphoid infiltration.

The aim of this work was to assess tumour-infiltrating lymphocytes (TILs) in gastric cancer with MSI status.

Methods: TILs density was scored on haematoxylin-eosin staining slides in thirty-seven gastric adenocarcinoma cases. Score ranged from no staining (0), weak staining (1), moderate staining (2) to strong staining (3).

Gastric adenocarcinoma microsatellite status was classified as MSI-high, MSI-low and microsatellite stable (MSS) after performing immunohistochemistry and genotyping.

Fisher exact test was used for statistical analysis.

Results: Among the thirty-seven cases, eight cases had MSI status: five were MSI-high and three MSI-low.

In the twenty-nine MSS cases, TILs were absent in ten and present in nineteen cases. Among these latter, TILs level was high in three cases, moderate in five cases and low in eleven cases. In gastric adenocarcinoma with MSS status, the number of cases with absent TILs and low-density TILs was significant (P<0.05).

In the five cases of MSI-high, TILs level was the highest in three cases and moderate in two cases.

In the three cases of MSI-low, TILs level was the highest in one case only and moderate in two cases.

Conclusion: Tumour infiltrating lymphocytes were present in all gastric adenocarcinoma MSI cases and in 19/29 cases with MSS status. However, the absence and the low density of TILs in gastric adenocarcinoma MSS cases were significant.

Funding: Tunisian Ministry of Higher Education and Scientific Research

PS-06-030

A double CD4/CD8α-β immunohistochemistry in duodenal biopsy with intraepithelial lymphocytes – could be that a first diagnostic step in celiac disease suspected cases?

W. Lewitowicz*, E. O'Regan, Z. Greally, E. Dobek, E. Maurycy, O. Gruszka, P. Lewitowicz

*Student Science Club at Collegium Medium, Jan Kochanowski University, Poland

Background & objectives: People who suffer from celiac disease present HLA II DQ2 or DQ8 which binds to gliadin and then activates CD4 T-cells in the intestinal mucosa. This autoimmune activation produces chronic inflammation of the small bowel mucosa, leading to gradual malabsorption.

Methods: A double immunohistochemistry was constructed using CD4 antibodies matched by DAB on brown and CD8(Ventana CP57 clone) antibody matched by RED. We applied CD8 α-β subunit because of their specificity and 80% sensitivity to celiac disease. This approach allowed us a full insight into CD4+ and CD8+ lymphocytes distribution. All CD8+ cases were serologically tested according to celiac disease guidelines.

Results: In group of 20 patients with chronic active gastritis caused by Helicobacter pylori and also in group of 12 patients with active ulcerative colitis we found IEL above 40/100. The double CD4/CD8 assay presented stromal dominance CD4+ lymphocytes and IEL CD8+ were detected in non-typical way. Unsurprisingly, celiac independent mucosal lymphocytosis was observed in 60% cases, but in 7 H. pylori cases and 3 among ulcerative colitis, anti-transamidase antibodies were detected. These cases were re-diagnosed as a principal entity with concurrent silent celiac disease.

Conclusion: In our opinion double CD4/CD8 staining provides more information then CD3 plus CD8 or the recommended singular test of CD3.

PS-06-031

The newly developed SP70 is a specific marker for gastric adenocarcinoma of fundic gland type

R. Luo*, W. Huang, C. Xu, Y. Hou

*Zhong Shan Hospital, Fudan University, China

Background & objectives: GA-FG is a novel and rare entity with low-grade malignancy. SP70,as a newly developed monoclonal antibody (McAb), was found to be sensitive in many tumours. This study aims to explore the diagnostic value and potential role of SP70 in GA-FGs.

Methods: A total of 33 cases were obtained from our institution (including 16 fundic gland polyps (FGPs), 9 oxyntic gland polyps/adenomas (OGPs), and 8 GA-FGs). We performed immunostaining for SP70 in different groups. SPSS 21.0 was used for statistical analysis.

Results: Immunohistochemically, 16/16 (100%) FGPs were diffusely positive for SP70, and some scattered SP70 positive cells were observed in OGPs (5/9, 55.6%); however, expression of SP70 was completely missing in GA-FGs (2/8, 25.0%), with statistical significant differences between groups (P < 0.001). In light to this significant finding, we are now carrying out further studies with large sample to confirm our results.

Conclusion: SP70 could serve as a potential biomarker to identify GA-FGs and hold. A diagnosis of GA-FG should be considered with the depletion of SP70 expression.

PS-06-032

Immunohistochemical evaluation in dysplastic and non-dysplastic Barrett’s oesophagus

K. Maslyonkina, E. Fedorov, A. Shidiy-Zakrua, L. Mikhaleva*

*FSBI RIHM, Russian Federation

Background & objectives: Morphological diagnosis of dysplasia in Barrett’s oesophagus (BE) is demanding and requires huge experience in gastrointestinal pathology. Despite using similar guidelines agreement between pathologists on presence and grade of dysplasia remains unsatisfactory. Immunohistochemical evaluation may improve diagnostics of dysplastic BE.

Methods: Morphological diagnosis of dysplasia in Barrett’s oesophagus (BE) is demanding and requires huge experience in gastrointestinal pathology. Despite using similar guidelines agreement between pathologists on presence and grade of dysplasia remains unsatisfactory. Immunohistochemical evaluation may improve diagnostics of dysplastic BE.

Results: DBE was presented in 17 patients (15,2%): 15 patients with low-grade dysplasia (LGD) and 2 with high-grade dysplasia (HGD). Hyperexpression of p53 was recognized in 15 (88,23%) cases of DBE (13 LGD, 2 HGD), staining in non-dysplastic BE (NDBE) was scattered. Expression of p16 was cytoplasmic in 9 (52,94%) cases of DBE (focal in 7 LGD, diffuse in 2 HGD), but scattered nuclear in NDBE. Immunostaining of Ki67 and cyclin D1 was marked in DBE and focal in NDBE. Expression of β-catenin changed pattern from membranous in NDBE and LGD to cytoplasmic and nuclear in HGD. Expression of AMACR was scattered in NDBE, focal in LGD and diffuse in HGD.

Conclusion: Immunohistochemical evaluation with p53, Ki67, cyclin D1, β-catenin and AMACR is a promising tool for precise diagnosis of dysplasia in patients with BE. It is helpful for distinguishing between NDBE, LGD and HGD. Further research is needed to assess prognostic value of these immunohistochemical markers in progression to oesophageal adenocarcinoma in patients with BE.

PS-06-033

Poorly differentiated clusters in colorectal cancer: a novel predictive factor associated with other relevant poor prognostic factors

L. Molina*, A. Sabio González, C. Cantero-González, R.J. Luque Barona

*UGC Anatomía Patológica, Hospital Universitario de Jaén, Spain

Background & objectives: Colorectal cancer (CRC) is currently the third most-commonly diagnosed cancer. Recently, poorly differentiated clusters (PDC) - small groups of ≥5 cells without glandular differentiation – had been proposed as a novel prognostic factor associated with other adverse histopathological findings.

Methods: In a cohort of 84 patients with surgically resected stage I-IV CRC -without neoadjuvant or adjuvant treatment-, we assessed retrospectively the prognostic value of several clinical-pathological variables, including PDC, tumour budding (TB), grade (G1-G3), lymphovascular (LVI) and perineural (PI) invasion, lymph node metastases, survival time and clinical stage. Statistical analysis was performed with SPSS.

Results: The cohort included 54 men and 30 women (40-90 years). 25 patients died from the disease, with a survival time between 0-50 months, and 7 patients died from causes other than disease. G2 (85.7%) was the prevailing histological grade and stage III (33,3%) was the predominant clinical stage. A 50% of the cases had metastasis to lymph nodes, 66.7% LVI and 28.6% PI. Regarding TB, 52.4% had a low score, 27.4% moderate and 20.2% high. PDC evaluation resulted in a low score in 58.3%, moderate in 21.4% and high in 20.2%. Histological grade (p <0.016), TB (p <0.0001), LVI (p <0.007) and PI (p <0.031) were significantly associated with PDC.

Conclusion: PDC grade seems to be a prognostic factor in CRC, as high PDC score in peritumoral regions were associated with other relevant poor prognostic factors, like grade, TB, LVI and PI. Given its easy identification, it may be included in the histological report. However, before it can be introduced in clinical practice, more studies should be performed in order to establish the optimal cut-off for each grade and give it broader validation.

PS-06-034

PRGS and in-situ immunophenotype as a combined „tool“ for monitoring the therapeutical efficiency of PIPAC in different peritoneal cancer diseases: a single centre experience

D. Neureiter*, E. Klieser, B. Neumayer, R. Gruber, J.P. Ramspott, P. Schredl, K. Emmanuel, T. Jäger

*Institute of Pathology, Austria

Background & objectives: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is able to induce regression of peritoneal metastasis (PM). The Peritoneal Regression Grading Score (PRGS) is used for assessment of therapy response. Nevertheless, the role of the related immune phenotype is still unknown.

Methods: We investigate retrospectively the PRGS of patients with peritoneal metastases in a single and reference centre for PIPAC in Austria. The PRGS was judged on four peritoneal biopsies with HE-staining and tumour-entity related immunostainings to quantify infiltrating tumour cells. Additionally, the effect of localized immune response was analysed by additional immunohistochemical staining for CD3, CD4, CD8, CD25 and TIA, too.

Results: Overall, peritoneal metastasis of the enrolled 48 patients (female/male: 26/22 with a mean age of 60.3 +/- 11.6 years) derived mainly of gastric cancer, malignant mesothelioma and ovary cancer. Based on a total sum of 134 PIPACs and 532 PRGS the mean [with confidence interval]/median PRGS after the first and after the last PIPAC were 2.6 [2.4-2.7]/3.0 and 2.0 [1.9-2.2]/2.0 with the lowest value of 1.1 [0.8-1.4]/1.0 at the fourth PIPAC. Additionally, we were able to link the PRGS and associated fibrosis to a specific regulative immune response. The PRGS and the observed immune phenotype were associated to intraperitoneal status and clinico-pathological parameters.

Conclusion: We demonstrated that the standardized applied PRGS is adequate to monitor the therapy response and outcome in cases with enhanced PM. The related in-situ immune phenotype supported this notion. In the future, the definitive predictive and prognostic role of the PIPAC induced immune reaction needs to be evaluated in prospective and international clinical trials.

PS-06-035

Liquid-based anal cytology in patients with HIV/AIDS: case series

D. Nunes Oliveira*, C. Cunha Frota., C. Vannucci Vasconcellos Nogueira Diógenes, B. Sobreira Camilo Soares, D. Rodrigues de Oliveira Pinto, B. Costa Bastos, J. Carneiro Melo, R. Dornfeld Escalante

*University of Fortaleza, Brazil

Background & objectives: Anorectal cytology (ARC) screening programs can allow the detection of small lesions for treatment and eradication of high-grade intraepithelial lesions and careful monitoring to detect early invasive cancer. Demonstrate the importance of ARC in HPV-induced lesions.

Methods: It was performed the liquid-based anal cytology in 219 HIV-positive patients, aged 18 to 75 years, 188 men and 31 women, with a mean age of 40 years.

Results: Among the 219 participants cytologically evaluated, we identified 12 people (5.47%) presenting atypical squamous cells of undetermined significance (ASCUS), a marker for a possible anal neoplasm. About this result, it is notable the higher prevalence of ASCUS in men (83.3%) compared to women (16.6%) in the survey. The average age of the patients was 43 years. Subsequently, it will be necessary to perform an anoscopy to explore other possible clinical findings in the examination.

Conclusion: Over the past 50–60 years the incidence of invasive squamous cell carcinoma of the cervix has decreased around 80% in countries which have implemented cervical screening program with quality, coverage, treatment and follow-up of the women. Likewise, anal screening programs may generate comparable success, since anal cytology sampling of the anal–rectal transformation zone can detect squamous intraepithelial lesions. Therewith, patients with ASC-US) or worse should be referred for anoscopy.

PS-06-036

Application of immunohistochemistry for gastritis staging assessment

M. Parygina*, S. Mozgovoi, A. Shimanskaya, V. Kolokoltsev, A. Kononov

*Omsk State Medical University, Russia

Background & objectives: Chronic gastritis (CG) staging is useful way to estimate the risk of gastric cancer. However, compliance with the international recommendations (the number and orientation of gastric biopsy specimens) is crucial. The usage of immunohistochemistry (IHC) techniques may improve staging assessment.

Methods: The study included antral mucosa specimens with absolute and metaplastic atrophy (n=465) from 155 patients with CG. IHC markers CDX2, MUC2, CD10, MUC5AC, MUC6 were used. MUC5AC, MUC6, MUC2 staining intensity was estimated on the basis of semiquantitative scale (from 0-absent to 3-marked). CD10 expression was assessed binary (presence/absence). CDX-2 staining was evaluated according to intensity: absent-0, weak/moderate-1, marked-2.

Results: In the samples with absolute atrophy MUC5AC and MUC6 were strongly expressed in the gastric surface/pits region and glands cells cytoplasm, respectively. The more was atrophy severity, the less was length of MUC6 expression zone. In intestinal metaplasia (IM) there was a nuclear CDX-2 staining in all cells, intensity varied from 1 in incomplete IM to 2 in complete IM. There was also strong cytoplasmic MUC2 expression in goblet cells, and brush border-associated CD10 expression in complete IM. Weak CDX-2 nuclear staining in the gastric epithelium had also been the most interesting. Focal complete IM was found in 75% of such specimens after additional histological sections.

Conclusion: The obtained data of the markers expression revealed CDX-2 protein as the most valid for atrophy assessment with sensitivity=86% [73.26-94.1] and specificity=74% [57.51-83.77]. Moreover, CDX-2 was expressed throughout the gland, which would be extremely helpful in absence of proper specimen orientation. This position gives us ground for thinking about CDX-2 as a possible surrogate marker of the gastric mucosal atrophy.

PS-06-037

CDX2 as a surrogate marker of gastritis staging

M. Parygina*, S. Mozgovoi, A. Shimanskaya, S. Glatko, A. Kononov

*Omsk State Medical University, Russia

Background & objectives: The usage of immunohistochemistry (IHC) may improve of chronic gastritis (CG) stage assessment in cases of potential non-compliance with the investigation protocol (fewer number of biopsy specimens). Marker of intestinal differentiation CDX-2 might be used for such approach.

Methods: CDX-2 expression parameters were evaluated in 155 CG cases assessed with OLGA system. The following parameters were analysed: expression pattern (EP, ≤3 cells – 1, >3 cells – 2, the whole gland – 3), CDX2-positive cells (PC, 0%-0, <5%-1, 5-25%-2, 25-50%-3, >50%-4), staining intensity (IS, none-0, weak-1, strong-2). CDX-2 expression indexes (EI) were calculated according by formula: EP+PC×IS.

Results: Correlations between CDX-2 index and CG stage were calculated according to artificial model of taking biopsies from one, two or three points of gastric mucosa. The highest r-Spearman's values were recorded for point 3 (stomach angle, r=0.673, p<0.01); 3 and 5 (greater curvature of the corpus, r=0.624, p<0.01); 1 (greater curvature of the antrum, r=0.592, p<0.01), respectively. Logistic regression models of CG staging based on CDX-2 index were constructed. The highest Se=80.4%, Sp=82.8% and Ac=83.9% were demonstrated by a model based on EI in biopsy specimens from points 1+3+5. EI less than 7 indicated CG stages I-II and greater than 7 for stages III-IV.

Conclusion: The adapted approach for CG stage assessment based on CDX-2 expression evaluation can be used if OLGA-system protocols are violated, number of specimens is low or samples are damaged (fragmentated, not oriented, etc). In such cases, CG staging with the usage of CDX-2 (EI) would be helpful approach to estimate CG stage in a particular patient and stratify the risk of gastric adenocarcinoma development.

PS-06-038

Gastric carcinoma with lymphoid stroma: a case report and literature review, with emphasis on different classification systems, including ISH/IHC classification as a molecular surrogate

S. Petronilho*, J. Azevedo, M. Jácome

*Pathology Department, IPO-Porto, Portugal

Background & objectives: Gastric cancer (GC) is the 3rd-cause of cancer-related mortality worldwide. The various current classification systems reflect its morphological, prognostic and molecular heterogeneity. Aim: Critically review/discuss the usefulness of different classification systems, applied to a rare case of GC with lymphoid stroma.

Methods: Case:62-year-old male with an infiltrative lesion in the incisura angularis/small curvature, which on resection measured 9x7cm and invaded the serosa. Microscopy showed a poorly differentiated neoplasm composed of polygonal cells with indistinct borders, arranged in irregular nests and permeated by abundant lymphocytes. EBER-ISH was positive. MLH-1, E-cadherin and P53 showed physiological expression. PD-L1 was positive in >50% of tumour cells.

Results: According to current GC classifications, our case would be included in the indeterminate-type (Lauren), infiltrative-type (Ming) and GC with lymphoid stroma (WHO) groups. These “morphological” classifications fail to reflect the driver tumorigenic mechanisms, and mostly lack clinical relevance or predictive/therapeutic value. The TCGA/ACRG molecular classifications partly answer these issues but are too expensive for routine use. Thus, a recent IHC/ISH based classification (mostly based on TCGA data) which divides GC in five clusters has emerged, which relies on the sequential evaluation of 4-markers: EBER-ISH, MLH1-IHC, E-cadherin-IHC and P53-IHC. The present case would be included in cluster-1 (EBV-associated). These tumours are frequently associated with PD-L1 expression, as seen in our case.

Conclusion: GC stratification based on IHC/ISH is widely accessible, reproducible, inexpensive and may represent a valuable tool in prognostic and therapeutic decisions. Regarding our case, GC with lymphoid stroma is a rare subtype, which is classically EBV-positive. Thus, it is often included in the EBV-positive cluster of the proposed IHC/ISH classification. These patients are mostly male, with poorly differentiated tumours, located in the body and have a better prognosis. Importantly, they frequently present PD-L1 and PD-L2 amplification, with potential therapeutic implications.

PS-06-039

The value of two sections on lymph nodes from patients with colorectal cancer in a routine setting

S. Pouplier*, S. Lehn, A. Kanstrup Fiehn, S. Eiholm

*Department of Pathology, Zealand University Hospital, Roskilde, Denmark

Background & objectives: Staging of patients with colorectal cancer depends on identifying an accurate number of lymph node metastases (LNMs). This study aimed to investigate if two sections of each lymph node would contribute to detect more metastases compared with a single section.

Methods: Surgical specimens from patients diagnosed with colorectal adenocarcinoma in our department during a three-month period were included. Two sections were cut from each macroscopically identified lymph node. A resident and a pathologist evaluated all slides for presence of LNMs and consequent staging due to one versus two sections. A third pathologist confirmed all cases of LNMs.

Results: In total 3218 lymph nodes with two sections from 121 patients were available. A metastasis was identified in 158 lymph nodes (4.91%). In six of these a LNM were present in only one of the sections (3.80%). Each of the six lymph nodes originated from six individual patients. In two of six patients the presence of an extra LNMs was crucial for the stage. In one patient the pN category was changed from N0 to N0(i+) and in the other patient from pN1 to pN2.

Conclusion: The histological assessment of lymph nodes from patients with colorectal cancer with two sections instead of a single section resulted in a small increase in number of detected metastases. However, the stage was changed in two patients, which might influence the choice of oncological treatment. A single extra HE-stained slide results in a minor extra workload at a limited expense and is thus a feasible method in most laboratories.

PS-06-040

Dysplasia in Barrett’s oesophagus - immunohistochemical features with potential prognosis value

S.M. Sabo*, G. Micu, A. Bastian, A. Voiosu, A. Cernat-Ștefan, R. Ardeleanu, M. Maria-Alexandra, C. Popp

*Colentina University Hospital, Romania

Background & objectives: In Barrett’s oesophagus (BE) normal squamous mucosa is replaced by metaplastic columnar epithelium. BE predisposes to dysplasia and adenocarcinoma. We aimed to investigate immunohistochemistry features that could reinforce the diagnosis of dysplasia or predict higher risk for malignancy.

Methods: Immunostaining for p53, Cyclin D1, and BCL2 was performed on 16 biopsies showing Barrett’s oesophagus separated in two groups: 8 cases with dysplasia and 8 cases without dysplasia, paired by sex and age. Expression was quantified in percentage of positive metaplastic mucosal cells. In the dysplasia group positivity was measured in dysplastic tissue and separately in non-dysplastic tissue.

Results: p53 was positive in all dysplasia cases and in just 3 non-dysplasia cases. Cyclin D1 was positive in all 16 cases, while BCL2 was light positive in 4 cases overall. Analysing comparatively the positivity percentages between the dysplastic tissue and the surrounding metaplastic tissue in 7 cases from group A (in 1 case dysplastic tissue was unfortunately depleted), we found a statistically significant (p=0.0482, t-test) mean difference (30.14%) in p53 staining. We also tested for differences in expression grades between the two groups, first comparing only non-dysplastic tissue and second comparing dysplastic epithelium from group A with metaplastic epithelium from group B, but found no statistically significant differences.

Conclusion: There is a significant degree of intraobserver and interobserver variability in the diagnosis of dysplasia in BE. Because finding of dysplasia in BE involves higher risk for malignant transformation and more extensive follow-up, there is a need for consistent methods of diagnosis. p53 positivity overall is proof for "field mutation" of metaplastic cells, while overexpression of p53 in dysplastic cells could be used for confirmation when in doubt and as a marker of poorer prognosis.

PS-06-041

Deeper sections reveal residual tumour cells in rectal cancer specimens diagnosed with complete pathological regression following neoadjuvant treatment

L. Slumstrup*, S. Eiholm, A.L.B. Bennedsen, I. Gögenur, A. Kanstrup Fiehn

*Zealand University Hospital, Denmark

Background & objectives: Guidelines and requirements for diagnosing complete pathological regression in rectal cancer after neoadjuvant treatment vary, and there is currently no consensus on best practice. We examined the consequences of this inconsistency for diagnostic accuracy and prognosis.

Methods: All patients diagnosed with ypT0 rectal cancer from 2015 to 2020 in our department were included (n = 23). In accordance with current British guidelines, three additional sections were cut from each FFPE block and stained with H&E. The distance between levels was 200 μm. Slides were reviewed by two pathologists for presence of residual tumour cells.

Results: Additional sections revealed residual viable tumour cells in seven patients (30.4 %) originally diagnosed with complete pathological regression. Of these, three patients (42.9 %) later had local recurrence or distant metastasis during the follow-up period, compared with two patients (12.5 %) in the group with no residual tumour cells in deeper sections (p = 0.14). In four of the seven patients with residual tumour cells, careful examination of the original slides revealed minute foci of tumour cells or areas suspicious for residual tumour. These areas were interpreted as non-malignant or overlooked at the time of diagnosis. The residual tumour was more obvious and easily recognized in the deeper sections.

Conclusion: Our results show that systematic use of deeper sections in evaluation of tumour regression in rectal cancer reveals the presence of residual tumour cells in a subset of patients originally diagnosed with complete pathological regression based on a single section per FFPE block. Furthermore, additional levels probably reduce the risk of overlooking small foci of tumour. Our results indicate that residual tumour increases the risk of recurrence, but due to the small sample size, the result is not statistically significant.

PS-06-042

IGF1 expression in gastrointestinal stromal tumours

I.A. Spiridon*, S.E. Giușcă, I.D. Căruntu

*"Grigore T. Popa" University of, Romania

Background & objectives: Gastrointestinal stromal tumours (GISTs) are the most frequent mesenchymal digestive tumours, characterized by activating mutation involving KIT. They present with a spectrum of biological behaviours, from benign to malignant, but little is known about the factors that influence these transformations.

Methods: We evaluated the immunohistochemical profile and expression of IGF1 in 46 cases of gastric GIST from adult patients. A panel of three markers (CD117, CD34 and DOG-1) were used for diagnosis. IGF1 expression was identified in the cytoplasm of tumour cells, displaying a finely granular pattern, and was scored into 3 classes of intensity: negative, weak and strong.

Results: On histopathological examination, the most frequent subtype of GIST was spindle cell (50%), followed by the mixed and epithelioid subtype. Most tumours were diagnosed pT2 and pT3, with over half of them having increased mitotic activity. IGF1 was expressed in the vast majority of cases (97.82%). Most GISTs had uniform granular cytoplasmic expression, while some had scattered areas of accentuated staining in the tumour cells (17.39%). Strong IGF1 expression was correlated with larger tumour size (p<0.001), while no statistical association with other clinicopathological factors such as histological subtype, pleomorphism, mitotic activity, gross characteristics or sex of the patients was observed.

Conclusion: The IGF axis plays a significant role in some malignancies, being actively involved in carcinogenesis and cancer proliferation. Our study highlights the increased expression of IGF1 in the tumour cells of most GISTs, a feature suggestive of a secretory profile. Whether these tumours are governed by an autocrine/paracrine mechanism or not, the association with tumour size could indicate the active role of IGF1 in tumour growth and development and possible involvement in their biological profile.

PS-06-043

Role of RORα In epithelial mesenchymal transition and carcinogenic pathways of gastric carcinoma, an immunohistochemical study

T. Talab*, S. El Mashad, A.S. Hemida, M.M. Soltan, A.S. Abdelnaby, A. Sohaib, M. Kandil

*Pathology Department, National Liver Institute, Menoufia University, Egypt

Background & objectives: Retinoid-related orphan receptor alpha (RORα) is a potent tumour suppressor gene. Epithelial mesenchymal transition(EMT) is involved in cancer invasion and metastasis. The aim is studying the role of RORα in EMT by immunohistochemical expression of RORα &E-cadherin in gastric carcinoma(GC).

Methods: Retrospective study of 73 surgically resected GC specimens with available corresponding adjacent non-tumour tissue and 167 cases of chronic gastritis collected from 2015 to 2020 at the archive of pathology department at faculty of medicine and National liver institute, Menoufia university. Tissue microarrays were constructed, RORα and E-cadherin immunohistochemical expression were assessed and then correlation with clinicopathological parameters and survival.

Results: RORα showed low expression in GC compared with adjacent non tumour and chronic gastritis(p=0.001). Low expression of RORα was associated with diffuse type GC(p>0.001), high grade tumours (p=0.017), positive nodal metastasis(p=0.013) and high tumour budding(p=0.010). E-cadherin showed low expression in GC compared with adjacent non-tumour and chronic gastritis(p>0.001). Most GC exhibited heterogeneous and negative expression of E-cadherin (69.9%&21.9%). Negative and heterogeneous expression of E-cadherin were significantly associated with high tumour budding(p=0.021), lymphovascular invasion(p=0.01), diffuse type GC (p=0.009) and advanced tumour pathological stage (p=0.005). RORα showed co-parallel correlation with percent of E-cadherin membranous positivity(p=0.040). Low RORα expression had a significant association to cancer-related death(p=0.036) when compared with high RORα expression.

Conclusion: RORα reduction in both GC and adjacent non tumour tissue indicate that it is a multistep carcinogenic factor. Co-parallel correlation between RORα and E-cadherin expression suggest its role in inhibition of epithelial mesenchymal transition in GC. RORα may be a potential therapeutic target for GC by utilization of RORα agonist or activator.

PS-06-044

Her2 testing of gastric cancer patients in Albania: results from a retrospective study

S. Zeneli*, M. Ikonomi, B. Cela, M. Alimehmeti

*NUHC Mother Teresa, Albania

Background & objectives: Gastric cancer (GC) is the fourth most common cancer in Albania. HER2-positivity rates in GC are reported with a wide range. There is no data for it in Albania.

Methods: A total of 192 patients, with primary GCs was retrospectively analysed for HER2 overexpression by IHC. Dual SISH, was used in only 20 GCs with equivocal results. We dispersed HER2 results by: gender and age, histopathological diagnosis and stage, type of the specimen. The results were compared.

Results: We examined by IHC 73.4% (141 cases) surgical and 26.5% endoscopic biopsies: 18.4% (26 cases) and 15.7% (8 cases) HER2 3+, respectively. HER2 overexpression (3+) was detected in 17.7% (34 cases). HER2 equivocal (2+) was detected in 24.5% (47 cases). 17.8% , 14%, 4.7% were respectively intestinal type, diffuse, signet ring and the rest adenocarcinoma NOS. GC prevailed in the group age of 61-70 yrs (31.70%; ), followed by 51-60 yrs (25%), 22.9% in 71-80-yrs. 20 cases analysed by SISH, showed Her2 amplification in 40% (8 cases). Economical restrictions and problems with preanalytical phase made it impossible to evaluate by SISH all 20 cases.

Conclusion: 17.7%of Albanian patients with primary GC were HER2-positive on IHC. There is no difference in biopsy and surgical specimen results. Economical restrictions can influence the results.

PS-07 | Digestive Diseases Pathology - Liver/Pancreas Posters

PS-07-001

The Role of STIM1 in Primary and Metastatic Pancreatic Ductal Adenocarcinoma

S.M. Abd Elhamed*, H.A.S. Aiad, N. Ehsan, M.M. Dawoud, A.S. Hemida, D. Sweed

*National Liver Institute/ Menoufia University, Egypt

Background & objectives: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies. Therefore, we aimed to evaluate the role of STIM1 in the pathogenesis of primary and metastatic PDAC.

Methods: This immunohistochemical study was carried out on 73 PDAC cases; 48 primary cases and 25 cases of PDAC metastatic to the liver or omentum. In addition, 23 cases from non-tumour pancreatic tissue and 10 normal pancreatic tissues as a control group were included. Tissue microarray (TMA) was prepared. Both epithelial and stromal STIM1 expression were evaluated in the studied groups.

Results: Both epithelial and stromal STIM1 were significantly overexpressed in primary PDAC cases compared to the adjacent non-tumour pancreatic tissue and normal pancreatic tissue groups (P<0.001, for all). High epithelial STIM1 expression was significantly associated with primary PDAC (81.3%) in comparison to metastatic group (60%) (P=0.049). However, there was no significant difference regarding stromal STIM1 expression between primary and metastatic PDAC (P=0.113). Epithelial STIM1 was significantly associated with the presence of significant intratumoral desmoplastic stroma (P=0.036).

Conclusion: Both epithelial and stromal STIM1 may have a role in the early development of PDAC. Targeting STIM1 may be effective in primary and metastatic PDAC patients. The significant epithelial STIM1 expression and its association with presence of desmoplastic stroma may indicate epithelial mesenchymal transition.

PS-07-002

Solid pseudopapillary neoplasm of the pancreas: a series of 11 cases

E. Ben Ammou*, W. Majdoub, A. Bdioui, M. Krifa, Z. Lajmi, A. Baccouch, T. Dahmoul, H. Hamchi, S. Hmissa

*Department of Pathology of Sahloul University Hospital, Sousse, Tunisia

Background & objectives: Solid-pseudopapillary neoplasms (SPN) of the pancreas are relatively rare epithelial tumours of low-grade malignancy that have no specific clinical or radiological features. Throughout this series we aim to focus on the clinical, microscopic and immunohistochemical characteristics of SPN.

Methods: We conducted a retrospective data analysis of 11 cases of patients diagnosed with SPN in our departments between January 2009 and March 2021.

Results: 1 out of the 11patients was male. Patients' age ranged from19 to78 years with an average of 29.

4 patients complained of abdominal pain. Only 2 showed portal-hypertension symptoms. In 2cases, SPN was an incidental discovery. The most common location was the pancreatic body. All-but-one patient underwent curative surgery, the remaining case was only biopsied. Grossly, the tumours were encapsulated brownish haemorrhagic friable nodules with an average size of 8.2cm (4–12cm). Only 4 were macroscopically cystic. Histologically, the common architecture alternates pseudopapillary and solid areas. Mitotic figures were rare to absent. Other features include cytoplasmic vacuolization(1case), hyaline globules(4case), degenerative changes such as necrosis(2cases) and calcifications(1case). All SPN stained with beta-catenin and CD10.

Conclusion: Familiarizing pathologists with SPN is important since complete surgical excision is usually curative. The overall prognosis remains good despite possible recurrences. When clinico-radiological signs are of no help ultrasound-guided fine-needle aspiration and histopathologic evaluation should do the deed.

PS-07-003

Alpha-smooth muscle actin positive stromal cells relates with stemness/cholangiocytic features in primary liver carcinomas

J. Espírito Santo*, A. Ladeirinha, A. Alarcão, L. Neves, E. Strelet, M. Campos, M. Reis, R. Santos, L. Carvalho

*Adult Liver Transplantation Unit, Coimbra Hospital and Universitary Centre, Portugal

Background & objectives: Alpha-smooth muscle actin (ASMA) expression in stroma suggests a crosstalk between epithelial and stromal cells through epithelial-mesenchymal transition. Primary liver carcinomas (PLCs) with stem/progenitor phenotype present worse prognosis.

Expression of ASMA/progenitor cell/cholangiocytic immunomarkers in a series of PLCs was evaluated.

Methods: In a series of 94 epithelial malignant liver tumours, concerning 51 consecutive patients undergoing hepatic resection/liver transplantation (2012-2016), classified according with 2019 World Health Organization (WHO) histopathological criteria, CK7/CK19, EpCAM (BerEp4) and ASMA immunoexpression in single or clusters of tumour cells were searched. Eighty-six tumours were hepatocellular carcinomas (HCCs); 3 were combined hepatocellular-cholangiocarcinomas (cHCC-CCs) and 5 were intrahepatic cholangiocarcinomas (iCCs).

Results: Thirty-eight HCCs expressed ASMA in stroma fusiform cells, 14 also in surrounding hepatocytes; 4 had discrete immunoexpression in tumour cells; 22 HCCs were CK7+, 4 CK7+/CK19+,6 EpCAM +, where 3 CK7+/CK19+.

The cHCC-CCs presented ASMA positive fusiform stroma cells and 1 case showed positive peritumoral hepatocytes; 2 CK7+, 2 CK19+, 3 EpCAM+ and 2 CK7+/CK19+/EpCAM+.

In the 5 iCCs, 4 had ASMA+ stroma fusiform cells and 2 ASMA+ peritumoral hepatocytes; all cases were CK7+/CK19+ and 3 EpCAM+.

Forty-one of the 45 tumours (28 patients) showing ASMA positive fusiform stroma cells had F3/F4 (METAVIR score) peritumoral fibrosis. In 6 patients tumour recurred within 6 years after curative surgery.

Conclusion: Then significant association (p<0,05) was observed between tumour stroma expression for ASMA and CK7, CK19 and EpCAM tumour cells expression. ASMA expression seems to be associated with stem/cholangiocytic cells in liver carcinomas. These preliminary results deserve interpretation for treatment definition in order to effectively modulate the malignant epithelial/stroma cooperation, beyond searching serological biomarkers.

Funding: This work was supported by ROCHE-APEF(Portuguese Association for the Study of the Liver) grant.

PS-07-004

Histological abnormalities of intra-hepatic vasculature in chronic viral Hepatitis B

A. Fitouri*, A. Zehani, B. Chelly, S. Rejaibi, I. Chelly, H. Azzouz, N. Maamouri, K. Bellil, S. Haouet

*Pathology Department, Rabta Hospital, Tunisia

Background & objectives: Chronic viral Hepatitis B (CVHB) is defined by chronic necrotizing and inflammatory lesions of the hepatic parenchyma.

The aim of study was to determine the abnormalities of intrahepatic vasculature in CVHB and their correlation with inflammatory activity and fibrosis stage.

Methods: Our study was retrospective on 30 cases of CVHB confirmed by the pathological examination of the liver biopsy over a period of 5 years (January 2013- April 2018) in La Rabta Hospital. For activity and fibrosis, the Metavir score was used. A statistical analysis was performed and the significance level was set at 0.05.

Results: This study included 13 males and 17 females with CVHB. The average age was 41 years. On histological examination, hepatitis activity was score 1 (N=7), 2 (N=19) and 3 (N= 4). The fibrosis was stage 1 (N= 10), 2 (N= 10) and 3 (N= 10). All cases showed vascular lesions. They were represented by portal angiomatosis (N=23), thrombosis of portal veins (N=7), sinusoidal dilatation (N=16), abnormal parenchymal draining veins (N=18), phlebosclerosis (N=14) and aberrant portal vessels (N= 24). Analytic study showed that activity is significantly associated with thrombosis of portal veins (p=0.02) and there is no significant association between vascular changes and fibrosis.

Conclusion: The vascular changes observed in chronic hepatitis involve angiogenesis lesions.

Two mechanisms explain the development of this angiogenesis:

First, it is part of the response to inflammation and the process of scarring that is triggered with chronic liver injury. Secondly, it is stimulated by hypoxia associated with fibrosis.

This angiogenesis has two consequences: the aggravation of fibrosis and the genesis of portal hypertension.

These lesions represent a sign of a progression of the disease.

PS-07-005

Colorectal cancer in patients with Inflammatory Bowel Disease and Primary Sclerosing Cholangitis

R.D.P. Lopez-Panqueva*, M. Ortiz-Pereira, J.H. Park Noh, C. Castillo, B. Mendoza de Molano

*Department of Pathology and Laboratories, Fundación Santa Fe de Bogotá/Universidad de Los Andes, Bogotá, Colombia

Background & objectives: The increasing incidence of Inflammatory Bowel Disease (IBD) in Latin-America enables us to explore extra-intestinal manifestations and complications of the disease. This study aims to describe IBD patients and PSC who developed colorectal cancer at a reference centre in Colombia.

Methods: A chart review study of patients with IBD between 1996 and 2019 at Hospital Universitario Fundación Santa Fe de Bogota. Patients diagnosed with PSC and colorectal cancer were reviewed and analysed.

Results: From a total of 327 patients with IBD, 16 patients with colorectal cancer were identified. 13 had UC and 3 CD, 10 patients were female and 6 male. Mean age of diagnosis of IBD was 56.28 years old. 9 patients had pancolitis. 11 patients (68.75%) had previous hospitalizations compared to cancer-free patients (31.25% n=5). 4.3 % (n=14) of all patients with IBD developed PSC and among these 14.3% developed colorectal cancer. Compared with patients without PSC 3.8% developed colorectal neoplasia. A positive association between PSC and colorectal cancer was obtained in patients with IBD (OR= 4.18, p= 0.008). Low-grade dysplasia was found in 6/327 patients (2.2%) and one high-grade dysplasia.

Conclusion: IBD increases the risk of PSC and colorectal cancer. These diseases share an underlying predisposition and a PSC-IBD phenotype has been described. This study reinforces a positive association between PSC-IBD and the increased risk of colorectal cancer. This increased risk is greatest with pancolitis and with higher degrees of endoscopic and histological inflammation. Chronic inflammation with cytotoxic and carcinogenic effects of bile acids in the colon are proposed mechanisms. PSC is underdiagnosed in IBD. Follow-up magnetic resonance cholangiography is recommended.

PS-07-006

Prognostic and therapeutic role of IgG4 liver infiltrate in patients with autoimmune hepatitis and overlap syndrome.

L. Naranjo Ruiz-Atienza*, A. Barreira-Díaz, F. Martínez-Valle, O. Orozco-Gálvez, M. Buti, M. Riveiro-Barciela, M. Salcedo-Allende

*Pathology Department, Vall d'Hebron University Hospital, Spain

Background & objectives: Some autoimmune hepatitis (AIH) have elevated serum IgG4 levels, and clinical characteristics of such patients are currently incompletely characterized. The aim of this study is to correlate IgG4 expression in patients with AIH and overlap syndrome (OS), with clinical data.

Methods: Retrospective single-centre study that includes 109 patients, 77% with AIH and 23% with OS. Liver biopsies were submitted for pathological study and IgG4 and IgG immunohistochemical techniques were performed in all cases. The presence of >10 IgG4 plasma cells per high magnification field was considered significant. A comparison of those biopsies with some clinical, analytical and therapeutic parameters was performed.

Results: 61% women, average age: 51. At diagnosis, 19% presented severe acute hepatitis, 15% liver cirrhosis, 83% ANAs ≥1/80 and 18% ANCAs. 18% presented significant IgG4 infiltrate, 24% with OS and 17% with AIH (p=0.29) and was associated with higher age, advanced liver disease, 32% having cirrhosis (p=0.01), and analytically with higher IgG, lower albumin and higher ANCAs; 95% had ANAs ≥1/80 compared to 84% among those without IgG4 infiltrate (p=0.19). Patients with significant IgG4 infiltrate required second-line drug use less frequently (6% vs 34%, p=0.02), but longer time to discontinuation of corticosteroid therapy (22 vs 14 months, p=0.04). Complete response and time to complete response was similar (p=0.49 and p=0.65).

Conclusion: Hepatic IgG4 significant expression in patients with AIH and OS was associated with more advanced liver disease, 32% having cirrhosis at diagnosis. Corticosteroid tapering was slower, although the need for second-line drug treatment was lower in these patients. The study of IgG4 in liver biopsies of AIH and OS may be a useful parameter to understand evolution and management of these patients.

PS-07-007

The real life of precision medicine in biliary tract cancers: a tertiary referral centre experience

F. Pedica*, N. Ahmed, D. Finocchiaro, F. Ratti, A. Casadei Gardini, V. Burgio, G. Marra, G. Grassini, L. Pecciarini, M.G. Cangi, C. Doglioni

*Pathology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy

Background & objectives: Biliary tract cancer (BTC) is the second most common malignant liver tumour with high aggressiveness and mortality. Intrahepatic and extrahepatic subtypes show different morphology, immunophenotype and molecular alterations, which should be investigated in the routine practice for precision therapy.

Methods: We performed a retrospective analyses of the molecular tests performed in our laboratory since July 2020 on a consecutive series of BTCs regarding the molecular alterations that have an impact on clinical decisions such as mutation of IDH1 and IDH2, FGFR2 fusions, mismatch repair proteins status, NTRK, ERBB2 and BRAF (as recommended by guidelines, immunohistochemistry, FISH and next generation sequencing).

Results: 27 patients affected by BTC were investigated after multidisciplinary meetings in the Liver Unit. We evaluated intrahepatic (85%) or extrahepatic cholangiocarcinoma (15%) on bioptic or surgical material. Targetable genetic alterations were found in 13 patients (48%), all affected by intrahepatic cholangiocarcinoma (ICC): 7 cases had IDH1 mutation (p.Arg132Cys, c.394C>T) and were poorly differentiated (G3) ICC “small duct type”, 1 IDH2 mutation (p.Arg172Gly c.514A>G) in ICC undergone neoadjuvant chemotherapy, 3 FGFR2 fusions ICC large duct type (2/3 G3), one had loss of PMS2 confirmed by genetic testing (and IDH1 mutation) and 2 large duct type ICC with loss of both MLH1 and PMS2. No NTRK fusion neither BRAF mutation were found.

Conclusion: Biliary tract cancer has recently gained attention thanks to targetable molecular alterations allowing for personalization of therapies in clinical practice. The detection of these alterations is routinely performed and is highly reliable both on bioptic and surgical material. The significant incidence of these alterations in our routine practice strongly support the real need of searching for them in clinical practice to establish the correct therapy for our patients and deeply understand the complex biology of biliary tract cancers.

PS-07-008

Incidence of gallbladder carcinoma in patients submitted to cholecystectomy: experience of the Centro Hospitalar e Universitário de Coimbra

F. Ramalhosa*, M.J. Amaral, P. Teixeira, M.J. Martins, R. Oliveira Caetano, M. Serodio, J.G. Tralhão, M.A. Cipriano

*Centro Hospitalar e Universitário de Coimbra, Portugal

Background & objectives: Malignant neoplasm of the gallbladder is uncommon with a poor long-term survival. Our aim is to identify the clinicopathological prognostic factors for survival in patients with Gallbladder cancer (GBC) submitted to surgery in our institution – a tertiary centre.

Methods: Forty-one patients underwent surgical treatment for GBC between 2008-2019 at our centre. The majority of the tumours (85.4%) were gallbladder adenocarcinomas; 41.5% of GBC were diagnosed incidentally, 65.9% of the patients had symptoms and 26.8% presented with acute cholecystitis. 46.3% of patients were stage III (AJCC) or higher. Analysis was conducted using SPSS.

Results: Median follow-up was 20.5 months (IQR 8.8-53.8) and median overall survival (OS) was 23 months. 3-year and 5-year survival rates were of 43.2% and 39.6%, respectively. On immunohistochemistry analysis, 6 patients (14.6%) were HER2+, but the HER2 status did not show influence on OS (median OS 18 vs 20 months, p=0.649); all had microsatellite stability. There was no association between HER2 expression and staging (p=0.35).

Conclusion: This study on GBC is, as far as the authors know, the first in Portugal. Surgery is still the gold standard for curative treatment and some patients with favourable prognosis may be identified. The over expression of HER2 could select patients for targeted treatment and prompt tissue sampling in unresectable patients.

PS-07-009

Clinicopathological study on morphological subtypes of hepatocellular carcinoma: a single-institution experience

C.H.A. Saler*, J.C. Beckervordersandforth, G. Roemen, S.W. Olde Damink, A. zur Hausen, M. Kramer, I. Samarska

*Department of Pathology and Internal Medicine, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center+, The Netherlands

Background & objectives: The WHO 2019 recognized several morphologic subtypes of hepatocellular carcinoma (HCC) with different pathological features, immune profiles, and clinical relevance of diagnosis. We aimed to analyse HCC subtypes in our population and assess the histological parameters.

Methods: The resection specimens of 56 cases, received between 2007 and 2021 at the Maastricht University Medical Center+, were revised according to the current WHO 2019 classification and the ICCR guidelines. The data on age, sex, surgical specimen, morphological subtypes, tumour grade, growth pattern, tumour extension, margins, vascular and perineural invasion, regional lymph nodes and distant metastasis were collected.

Results: 56 resection specimens from 20 women and 36 men with the median age of 64 years [range 26 to 88 years] were obtained. The two most common morphologic subtypes were steatohepatitic and clear cell HCC. However, 36 cases (64.3%) demonstrated multiple morphological patterns. One tumour (1.7%) revealed a prominent lymphocytic infiltrate, suggestive of a lymphocyte-rich HCC. The syncytial cell-like giant cells were found in 15 cases, usually in less than 5% of the total tumour volume. The solid growth pattern was most common, yet we often observed concurrent heterogeneous growth patterns. Forty cases (71.4%) showed satellitosis. Perineural growth was an infrequent feature, identified only in two cases (3.5%).

Conclusion: While steatohepatitic and clear cell HCC were the most common morphologic subtypes, the majority of cases demonstrated multiple morphological patterns and heterogeneous growth patterns. Clear diagnostic criteria for the different morphological subtypes are necessary for tumours with heterogeneous morphology. Precise subclassification of HCC, particularly in cases with distinct morphologies and diverse tumour growth patterns, may facilitate an accurate prognostication, follow-up and treatment.

PS-07-010

Role of CD44/RhoA in the regulation of oncogenic YAP in hepatic carcinogenesis

J. Schwenke*, S. Manmadhan, B. Kohnke-Ertel, C. Rupp, P. Shokoohi, U. Bauer, M. Ringelhan, C. Mogler, R. Schmid, U. Ehmer

*Internal Medicine II, Klinikum rechts der Isar, Technische Universität München, Germany

Background & objectives: Activation of oncogenic YAP is an early event in hepatocellular carcinoma (HCC). However, it remains unclear how YAP is activated in HCC. Several mechanisms, including control by Hippo signalling, beta-catenin signalling, or a CD44/RhoA- dependent pathway have been described.

Methods: YAP and CD44 expression were assessed by histopathology in human and mouse HCC. Human HCC cell lines HepG2, HuH7 and Mahalavu were treated with the CD44 antibody IM7 and Rho inhibitor rhosin. Treatment was evaluated via MTT proliferation assay. Protein and mRNA expression were quantified by western blot, immunofluorescence staining and quantitative real-time PCR, respectively.

Results: Immunohistochemistry staining in mouse and human HCC showed a correlation of the expression of CD44_v6 and active, nuclear YAP. Additionally, the expression of YAP target genes correlated with the expression of CD44 by mRNA in mouse and human HCC. While the CD44 antibody IM7 didn´t exert any effect on cell proliferation, rhosin – an inhibitor of downstream RhoA – decreased the proliferation in HCC cell lines significantly. By western blot, only slightly reduced YAP and P-YAP protein levels were observed, but immunofluorescence staining of HepG2 and Mahalavu demonstrated a significant increase in inactive, cytoplasmic YAP upon Rhosin treatment. In HepG2 cells, rhosin treatment decreased the expression of YAP target genes.

Conclusion: Correlation of YAP and CD44 staining in human and mouse HCC indicates that a previously described CD44/RhoA axis could regulate the activation of oncogenic YAP in HCC. Inhibition of RhoA in human hepatoma cells reduced proliferation and correlated with inactivation of YAP. If targeting of RhoA could therefore present a promising treatment strategy in human hepatocellular carcinoma is subject to further investigation.

PS-07-011

ESM1 as a predictive marker of tumour recurrence in patients who underwent liver transplantation for hepatocellular carcinoma

M. Tantawy*, M. Abd El-Wahed, M. Shabaan, D. Taie, A.S. Hemida, N. Ehsan

*Department of Pathology, National Liver Institute, Menoufia University, Egypt

Background & objectives: Angiogenesis participates in cancer pathogenesis and metastasis. Endothelial-cell-specific molecule-1 (ESM-1) is overexpressed in tumour endothelial cells in hepatocellular carcinoma (HCC). This study aimed to investigate ESM1 as a marker of tumour recurrence in patients who underwent liver transplantation for HCC.

Methods: This retrospective study included 52 patients who had undergone liver transplantation for HCC during period from March 2010 to March 2021. Clinical, laboratory and histopathological data were collected from medical records of Pathology Department, National Liver Institute, Menoufia University. Sections from tumour and non-tumour liver tissue were prepared for Immunohistochemical staining with ESM1 antibody.

Results: In the present study, 34.6% of HCC cases showed positive ESM1 expression in tumour, while all non-tumorous tissue showed negative ESM1 expression. Most cases (71.4%) with HCC recurrence were positive for ESM1 expression. ESM1 expression was significantly associated with age ≥ 55 years. Univariate analysis showed that ESM1 positivity (p= 0.043), Alpha-fetoprotein (p=0.021), tumour size ≥3cm (p=0.001), advanced tumour pathologic staging (p=0.002) and microscopic lymphovascular invasion (p=0.019) were significantly associated with tumour recurrence after liver transplantation for HCC. Value of ESM1 expression as a predictor of HCC recurrence after liver transplantation was evaluated and showed 71.43% sensitivity, 71.11% specificity, 27.78% positive predictive value, 94.12% negative predictive value and 71.15% accuracy.

Conclusion: Immunohistochemical expression of ESM1 could be used as a marker of poor prognosis that predicts tumour recurrence in patients planning for liver transplantation in HCC cases. ESM1 might be used to predict outcomes in patients with HCC diagnosed through percutaneous biopsy or hepatic resection.

Key words: Endothelial-cell-specific molecule-1, Hepatocellular carcinoma, liver transplantation, Recurrence.

PS-08 | Endocrine Pathology Posters

PS-08-001

Injuries associated with papillary carcinoma in thyroid surgical parts in the department of pathology of the federal university of Ceará, Brazil, in the period from July 2016 to December 2020

P. Aguiar*, T.N. Albuquerque Gomes Nogueira, J. Souza, A. Lobo Ramos, G. Holanda Maia, G. Carvalho

*Federal University of Ceará, Brazil

Background & objectives: Papillary thyroid carcinoma (PTC) is the most common malignancy of the thyroid. The verification of coexistence with associated findings is important for the monitoring and prognosis. The article aims evaluate the association between coexisting lesions in patients diagnosed with PTC.

Methods: Realized through the analysis of an institutional historical series involving all cases submitted to partial or total thyroidectomy for papillary carcinoma, performed in the department of pathology of the federal university of Ceará, Brazil, in the period from July 2016 to December 2020.

Results: A total of 110 patients were included in the study, with 69 (63%) associated with some finding, the most common being: lymphocytic thyroiditis (17%) and follicular adenoma (17%), in addition, 32% of patients had more than one finding. We observed a preponderance of women, representing a total of 101 (92%) among the cases, with a mean age of 55.2 years. Of the total, 2 (2%) patients had perineural invasion, 15 (16%) angiolymphatic invasion and 24.2 (22%) extraglandular extension. Regarding anatomopathological staging, 54% of pT1 cases, 14% pT2, 21% pT3 and 3% pT4.

Conclusion: In literature are few studies that analyse the presence of lesions associated with PTC and its implications. In our study, 65% of the cases of PTC were associated with one or more findings and their presence was associated with the presentation of disease at an earlier stage. It is possible that the search for medical treatment in the face of benign thyroid lesions favoured the finding of PTC at an earlier stage and influenced the prognosis and recurrence.

PS-08-002

Predictive Factors of Lymph Node Metastasis in Thyroid Papillary carcinoma

M. Ben Thayer*, F. Khanchel, I. Helal, W. Hizem, A. Hmidi, E. Ben Brahim, R. Jouini, A. Chadli-Debbiche

*Department of Pathology, Habib Thameur Hospital, Tunis, Tunisia

Background & objectives: Papillary thyroid carcinoma (PTC) is associated to lymph node metastases (LNM), in up to30 to 80%. However, pathological predictors of LNM have yet to be established.

We aim to determine clinicopathological predictive factors for LNM in PTC.

Methods: We retrospectively analysed 81 patients who were diagnosed with PTC in the Department of pathology of Habib Thameur's Hospital between January 2016 and December 2020. Univariate and multivariate logistic regression was used to analyse the correlation between clinicopathological characteristics and the LLNM of PTC.

Results: A total of 81 patients was included. They were 11 men and 70 women, with a mean age of 42,8±12,6 years. Thyroidectomy and loboisthmectomy were performed in 70 and 11 patients respectively. Mean tumour size was> 2cm in 38 patients. The tumour was in the lower third in 24 cases. Vascular invasions were diagnosed in 20 cases and capsular effraction in 35 cases. Perithyroid involvement was noted in 14cases.The mean number of nodes dissected was 11,5. In 43 cases the number of nodes dissected was>5. Correlation between lymph node status and different clinico-pathological predictives revealed a statistically significant correlation with number of nodes dissected>5 (p=0,004). There was not statistically signification correlation with the other predictive factors.

Conclusion: Management of lymph node dissection in PTC is still controversial. The factors that predict LNM in PTC are important for treatment assessment. The results of this study identified only one statistically significant independent predictive factor for LNM in PTC: number of lymph nodes dissected. Therefore, lymph node dissection should be as complete and exhaustive as possible in case of PTC. However, the morbidity of thyroid surgery is increased when neck dissection is performed.

PS-08-003

Temporal changes in the epidemiological profile of well-differentiated follicular cell-derived thyroid carcinomas in our institution over a 15-year period: a retrospective, transversal study of 722 cases

A. Borda*, A. Zahan, N. Berger, A. Nechifor-Boilă

*Department of Histology, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu-Mureș, Romania

Background & objectives: Our study aimed to document the time trend evolution of papillary (PTC) and follicular (FTC) thyroid carcinomas in our institution over a 15-year period and to assess the impact of 2017 WHO classification of thyroid tumours on their epidemiological tendency.

Methods: All PTCs and FTCs registered in our department between 2001 and 2015 were re-evaluated. The histological diagnosis was established according to both 2004 and 2017 WHO diagnostic criteria. Non-invasive encapsulated follicular variant of PTCs were reclassified as NIFTPs (non-invasive follicular thyroid neoplasms with papillary-like nuclear features). Tumours’ time trend evolution (according to 2004/2017 WHO classifications) was analysed and compared.

Results: Our study included 701 PTCs and 21 FTCs. Irrespective of whether the WHO 2017 or 2004 diagnostic criteria were applied, we noticed a statistically significant increasing annual rate of PTC (from 81.6% in 2001-2003 to 97.8% in 2013-2015, p=0.001 and from 85.7% in 2001-2003 to 98.2% in 2013-2015, p=0.001, respectively). However, application of 2017 WHO diagnostic criteria (excluding NIFTP from the PTCs) resulted in a significant decrease of follicular variant of PTC cases (n=190/701, versus n=65/701, dif. 17.82%, IC: 13.7-21.8%, p< 0.0001). FTCs revealed a significant decreasing trend in the annual rate only at the beginning of the study period (from 14.3% in 2001-2003 to 1.8% in 2013-2015, p<0.0001).

Conclusion: Our data revealed a significant increasing trend of PTCs treated in our institution over a 15-years period, irrespective of whether the WHO 2017 or 2004 diagnostic criteria were applied. However, the introduction of the NIFTP category resulted in a significant reduction in the number of PTCs. FTC remains rare.

PS-08-004

Predicting biological behavior of parathyroid neoplasms by morphological and immunohistochemical features

M. Bugdayci Uner*, H. Uner, MD, C. Sokmensuer, MD

*Department of Pathology, Hacettepe University Faculty of Medicine, Turkey

Background & objectives: Parathyroid neoplasms show a wide spectrum of morphology (adenoma-carcinoma), which is difficult to predict biological behaviour by histomorphology. The aim of this study is to evaluate morphological and immunohistochemical predictors of biological behaviour of parathyroid neoplasms in a wide study-set.

Methods: We re-evaluated 888 parathyroidectomy specimens between 2000-2020. We re-evaluated the H&E slides of recurrent and atypical adenomas besides the carcinomas, using morphological criteria such as mitotic activity, necrosis, fibrous bands, growth pattern, perineural/vascular/capsular invasion, and metastasis. We also reassessed recurrent cases (first and the second biopsy). Then we correlated the morphological data with the follow-up data to predict biological behaviour.

Results: In 20 years’ time, 656 cases were reported as parathyroid adenomas (F/M: 509/147, avg. 53,2 yrs) including 7 recurrent adenomas (avg. 41,3 yrs), 22 atypical adenomas (F/M: 10/12 and avg. 52,7 yrs), one of which was recurrent, and 12 of the adenomas were located ectopically (9 intra/juxta-thymic and 3 intra-thyroidal). There was 15 carcinomas (F/M: 5/10, avg. 47 yrs), two of which were recurrent, revealing ki-67 in a range of 1%-10%, in the contrary ki-67 was up to 30% in atypical adenomas. Both neoplasms revealed fibrous bands and variable mitotic activity but only carcinomas showed lymphovascular & capsular invasion besides higher p53 expression.

Conclusion: Parathyroid neoplasms are a difficult group of neuroendocrine tumours because markers such as ki-67 and morphological findings such as fibrous bands, growth patterns and mitotic activity are not always helpful to predict the biological behaviour or to distinguish an adenoma from a carcinoma. However, known immunohistochemical markers ,such as p53, may help more to the pathologist as well as the other markers (cyclin D1, p27 etc) and clinical & radiological correlation of the case.

PS-08-005

Carcinomas of the thyroid with Ewing family tumour element (CEFTEs): a case report

E. Caranfil*, P. Khneisser, C. Kanaan, L. Lamartina, J. Scoazec, A. Al Ghuzlan

*Institut Gustave Roussy, Département de Biologie et Pathologie Médicales, Villejuif, France; Universitatea de Medicina si Farmacie "Grigore T.Popa",Iasi, Romania

Background & objectives: Few cases of “Carcinoma of the Thyroid with Ewing Family Tumour Element (CEFTEs)” were reported recently, as a small-cell, non-neuroendocrine thyroid tumour displaying expression of p63, CD99 and cytokeratins associating a ESWR1-FLI1 rearrangement. Thyroglobulin and Calcitonin are typically negative.

Methods: We present the case of a 75-year-old female, who had a history of mucinous lung adenocarcinoma and presented with a large infiltrative thyroid mass associating pulmonary and cervical lesions. Total thyroidectomy with lymph node dissection was performed and chemotherapy was started for suspicion of lung adenocarcinoma relapse. Histological examination with subsequent immunohistochemical and molecular studies were realised.

Results: The tumour has a solid architecture with a very focal follicular pattern without papillary nuclear features. Tumour cells exhibited loss of follicular markers such as TTF1 and TG (except for a few zones), were negative for Calcitonin and CEA as well as neuroendocrine markers. P63 and CD99 expression was strong and diffuse. Ki67 was overall low with an average of 5%. Lymph node metastases showed very focal expression of CT and CGA. Molecular study showed a rearrangement of the ESWR1 gene with a ESWR1-FLI1 fusion transcript and no Ret mutation was found. The diagnosis of CEFTE was proposed. The patient was stable under simple surveillance after 56 months of follow-up.

Conclusion: We report a case of CEFTE which is a rare and newly described entity. It is believed to arise from either solid cell nests or a pre-existing papillary thyroid carcinoma. Since they present a small cell cytology and ESWR1 rearrangement, the distinction from a typical Ewing tumour is challenging. Most studies describe this entity as having a good prognosis, as was the case for our patient, and, unlike our case, occurring in young patients.

PS-08-006

Primary bilateral macronodular adrenal hyperplasia in a familial cluster with a novel ARMC5 mutation

D. Doutel*, D. Cavaco, F. Santos, R. Cabrera

*Instituto Português de Oncologia de Lisboa Francisco Gentil, Portugal

Background & objectives: Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a rare cause of Cushing syndrome (CS). ARMC5 is the most frequently mutated gene in PBMAH. We report the clinicopathologic features of two cases within a familial cluster with a novel ARMC5 mutation.

Methods: A 58-year-old man with CS and bilateral nodular formations of the adrenal gland was diagnosed with PBMAH. ARMC5 sequencing analysis was performed and he underwent bilateral adrenalectomy. His 31-year-old son had mild CS symptoms and unilateral increase in volume and nodularity of the adrenal gland. He was found to have the same genetic alteration and was submitted to unilateral adrenalectomy.

Results: The adrenal gland was multinodular in both cases, the largest nodule measured 28 mm in the son and 25 mm in the father. Histologically, the nodules were mainly comprised of fasciculata zone-like cells, with varied degrees of lipid depletion. The permeated adrenal cortex was scarce and atrophic. ARMC5 sequencing analysis revealed a heterozygous mutation c.152G>T(p.Gly152) on exon 1 in both cases. After surgery, there was an improvement in metabolic control, blood pressure, proximal muscle strength and weight loss in both patients.

Conclusion: Mutations associated with ARMC5 and PBMAH are still being discovered. In patients presenting with CS and multinodular adrenal glands with macronodules, it is important to be aware of PBMAH, and test for it, even in cases with unilateral enlargement of the gland and indolent clinical behaviour, as in the son’s case. Also, unilateral adrenalectomy may be effective, at least initially, in patients with mild PBMAH.

PS-08-007

Can histomorphological features predict lymph node metastasis in papillary thyroid microcarcinoma?

M. Gündüz*, I. Urla Gündüz, N. Gül, İ.C. Sormaz, N. Aksakal, Z.G. Özkan, S. Önder, G. Yegen

*Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Turkey

Background & objectives: Papillary thyroid microcarcinomas (PTMC), despite their favourable outcome, metastasise to lymph nodes occasionally. Our purpose is to define histomorphological features that are associated with lymph node metastasis (LNM) in PTMCs.

Methods: 248 cases, diagnosed as unicentric PTMC, that have at least 2 years follow up or that were metastatic at the time of diagnosis, were reviewed. Age, gender, tumour diameter, tumour borders, histologic subtype, nuclear score, tumour infiltrating lymphocytes, desmoplasia, psammoma bodies, presence of papillary structures, capsule, lymphatic, vascular and perineural invasion status were noted.

Results: Mean follow up time was 79 months (18-155 months). Among 248 cases, 20 cases (8,1%) had LNM, of which 2 also had distant metastases (to the mediastinal lymph node). In univariate analysis, LNM was significantly more frequent in males, under the age of 50, and in tumours that are >7 mm and classical type, also in tumours that have lymphatic invasion, nuclear score 3, psammoma bodies, papillary structures and infiltrative borders (p<0,01). Presence of desmoplasia was also correlated with LNM (p<0,05). Other features evaluated were not relevant with LNM. Lymphatic invasion and male gender were found to be independent variables in multivariate analysis.

Conclusion: Despite their favourable outcome, PMCs metastasise to lymph nodes occasionally. Lymphatic invasion and male gender were found to be independent predictors of LNM. Besides, patients harbouring high risk histology such as classical type histology, high nuclear score, infiltrative tumour borders, desmoplasia and psammoma bodies should be carefully followed-up.

PS-08-008

Features of Oct4 expression in neuroendocrine tumours of different types

L. Gurevich*, E. Bondarenko, O. Vasyukova, L. Mikhaleva

*RPOD Human Health, Russia

Background & objectives: The transcription factor Oct4 plays a decisive role in embryogenesis, as well as in the survival of tumour cells of poorly differentiated tumours, which is the reason for their progression and resistance to chemotherapy.

Methods: Immunohistochemistry was used to study 85 NET: lung -21 (3 typical, TC, 6 atypical, ATC, carcinoids, 7 SC-NEC, 3 LC-NEC), 6 thymus (ATK - 5, LC-NEC -1), 18 stomach, 17 intestines (10 small, G1, 4 intestine, 3 rectum, G1), 23 pancreas, 3 Merkel carcinomas. The expression of Oct4 in the cytoplasm of cells was assessed in points (0-3+).

Results: Of 64 low grade NETs of all localizations, expression was detected in 62.5% (40/64), in 100% NET in the stomach and small intestine. From 21 NEC to 1 LC-NEC stomach. The most intense expression (3+), was characteristic of NET small intestine and stomach (90%, 92.3%), and in 2 ACTH-positive ATCs of the thymus. Moderate expression of Oct4 (2+) was detected in 19.8% NET: 50% ATC lung, 39,1% NET pancreas, 2 NET small intestine and stomach. Oct4 expression was absent in all NEC lung, stomach (except 1 LC-NEC), large intestine, Merkel carcinomas, NET rectum, 35,8% (5/13) TC/ATC lung/thymus, 60,9.8% (14/23) NET pancreas.

Conclusion: ECL-cell NETs of the stomach and small intestine are characterized by intense cytoplasmic expression of Oct4, which can be used as an additional diagnostic and prognostic criterion, as well as a cellular target for the development of new approaches to their treatment.

PS-08-009

Thyroid nodules: confrontation of echographic and histological data

I. Helal*, F. Khanchel, A. Hmidi, M. Ben Thayer, F. Zenaidi, E. Ben Brahim, R. Jouini, A. Chadli-Debbiche

*Habib Thameur's Hospital, Tunisia

Background & objectives: The Thyroid Imaging-Reporting And Database System (TI-RADS) classification is sensitive but not very specific, leading sometimes to abusive cytological and histological explorations. Our study aimed to evaluate the sensitivity and specificity of the TI-RADS classification by reference to histological results.

Methods: A cross-sectional, retrospective and descriptive study was conducted at Pathology department of Habib Thameur Hospital between January 2016 and December 2017. The nodules were classified according to the TI-RADS. The diagnostic value of this score by reference to histology data was evaluated by calculating sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV).

Results: Eighty-one nodules have been identified. The mean age was 46,7 years and the sex ratio (M/F) was 0.07. Fifty nodules were classified as suspect (TI-RADS IV and V) and 31 non-suspect (TI-RADS I, II and III). The histological study revealed 56 benign lesions and 25 carcinomas which 96% were papillary carcinomas. Statistical analysis of these results showed a significant relationship between TI-RADS classification and histological data with a Se of 88%, a Sp of 48,21%, a NPV of 9,7% and a VPN of 98%.

Conclusion: Our study confirmed the good sensitivity of the TI-RADS system (88%) with excellent VPN (98%). However, its low specificity (48,21%) prompted us to propose the generalization of other evaluation systems (EU-TIRADS and ACR TI-RADS) with a simpler and more precise notation, allowing better management of thyroid nodules.

PS-08-010

Cribriform-morular variant of papillary thyroid carcinoma– a case series

N. Mittal*, S. Rane, M. Bal, A. Patil

*Tata Memorial Center, Homi Bhabha National University, India

Background & objectives: Cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) is among the rarest of all variants of Papillary thyroid carcinoma(PTC). Distinct female predominance and association with familial adenomatous polyposis (FAP) characterize this unique variant of PTC.

Methods: Retrospective clinic-pathological review of nine cases of CMV-PTC diagnosed over a period of 5 years (2017-2021) was undertaken. The clinical findings were recorded from the electronic record system, and imaging details were obtained from the picture archiving and communication system (PACS). There were 8 women, and one male patient. The mean age was 27.7 years (age range;16-38 years).

Results: Multifocality in 22.2%, Left lobe involvement in 77.8%, size range of 2.8-7.5cm, and clinically negative nodes in all were the most notable clinic-radiological findings. All cases, on histology, resembled columnar cell variant of PTC. Solid areas in 22.2%, non-squamous morules in 55.6% cases(highlighted by Bcl2 and CD10), mitosis >5/10hpf in 11.1%, microscopic extrathyroidal extension in 22.2%, lack of necrosis or nodal metastases were other salient findings. Immunohistochemistry showed diffuse nuclear positivity for Beta-catenin(100%), ER, PR, and TTF1. Endoscopy revealed asymptomatic colonic polyposis in 3 patients (including the male patient), which on histology were tubular adenomas indicating associated FAP. All patients are alive without disease at last follow-up (range: 3-48 months).

Conclusion: CMV-PTC is rare and underdiagnosed; 4 out of 9 cases with an outside histology were misdiagnosed as classical PTC, and not CMV-PTC. Lack of morules in all cases, and rarity and lack of awareness especially occurrence in male gender being possible causes. CMV-PTC preceded FAP in all our cases, and as early detection and treatment of FAP is life-saving; the importance of recognizing CMV-PTC cannot be overemphasized.

PS-08-011

Clinico-pathological and molecular characterization of 9 cases of tall cell variant of papillary thyroid carcinoma

A. Nechifor-Boila*, A. Zahan, C. Bănescu, A. Borda

*Department of Histology, UMFST Târgu Mureş, Romania

Background & objectives: Tall cell variant of papillary thyroid carcinoma (TCPTC) is a rare, but more aggressive variant of PTC. We aimed to investigate the clinico-pathological and molecular characteristics of 9 cases of TCPTC registered in our Department over an 8-years period.

Methods: All PTC cases registered in our department between 2008-2015 were reviewed. Nine cases of TCPTC with available follow-up data and well-preserved formalin-fixed and paraffin embedded tumour blocks for molecular analysis were identified and included in the study. All TCPTCs were subjected to RT-PCR amplification targeting the BRAFV600E and RAS (KRAS, NRAS, HRAS) somatic mutations.

Results: The mean age of the patients was 52.48±14.84 years-old; all but one were females. The mean tumour size was 24.95±11.34 mm and 3 cases were multifocal. Extrathyroidal extension, with tumour invasion into the strap muscles of the neck was documented in 5 cases. Lymph node dissection was performed in 4 cases; of these, three displayed lymph node involvement. All patients were treated by total thyroidectomy and received radioactive iodine therapy. During the follow-up period, one case (staged pT1bN1) developed lung metastasis 65 months after the initial diagnosis. With regard to the molecular profile, six (66.7%) TCPTCs were BRAFV600E positive, whereas none of the cases was associated with RAS mutations.

Conclusion: Tall cell histology represents a poor prognostic factor in PTCs. Our results emphasize the importance of recognizing and reporting TCPTC because of its more pejorative prognosis, with an increased risk of local invasion, lymph node and distant metastasis, as well as high frequency of BRAFV600E mutation.

Acknowledgement: This work was supported by the University of Medicine and Pharmacy of Tîrgu-Mureş “George Emil Palade” of Târgu-Mureș Research Grant No. 10127/4/17.12.2020.

PS-08-012

A rare parathyroid neoplasm as a mimic of hyperplastic goitre: a case report

T. Oliveira*, I. Alves

*Department of Pathology, Hospital de Santa Maria, CHULN, Portugal

Background & objectives: Parathyroid carcinoma is a rare tumour with a typical clinical presentation of parathyroid hormone excess signs and hypercalcemia, but may rarely be indolent, producing only mass effect symptoms. Herein, we present a non-functioning parathyroid carcinoma case mimicking a hyperplastic goitre.

Methods: A 55-year-old woman with a diagnosis of hyperplastic goitre 8 years prior, revealed a slowly expanding neck mass that had recently induced dysphagia. Biochemical analysis revealed normal serum calcium and parathyroid hormone levels; anti–thyroid peroxidase and anti-thyroglobulin antibodies were both negative. Nonetheless, the fine-needle biopsy of the mass suggested a lymphocytic thyroiditis and a thyroidectomy was performed.

Results: Grossly, the thyroidectomy specimen weighted 148 g and was almost totally replaced by a multinodular tumour with 12 cm in largest axis, with a tan cross-section and focal haemorrhage. Histologically, the tumour showed a solid nodular pattern, subdivided by broad fibrous bands and was composed of mildly pleomorphic chief cells with round to ovoid nuclei, some with dense chromatin and prominent nucleoli. There was capsule invasion and angioinvasion. These cells demonstrated immunoreactivity for cytokeratins 8/18, chromogranin-A and parathyroid hormone (multifocal) and negativity for calcitonin, thyroglobulin and TTF-1. The tumour was diagnosed as a parathyroid carcinoma, clinically non-functioning, stage pT2.

Conclusion: Rarely, parathyroid carcinoma may present as a non-functioning cervical mass and remain clinically unsuspected, making it a diagnostic challenge by mimicking thyroid carcinomas or hyperplastic goitre, as our case was. Save for a surgery-related left vocal cord paralysis, the patient remains disease-free 11 months after the surgery, maintaining close follow-up without current need for further oncologic treatment.

PS-08-013

Anaplastic thyroid cancer: PD-1 and PD-L1 expression in a series of 13 cases

E. Quirós Arapé*, L. Ferrazza, A. Domingo, N. Ruiz, T. Serrano, N. Baixeras, J. Puig de la Bellacasa Suils, E. De Lama, J.M. Francos, A. Petit, X. Matias-Guiu

*Department of Pathology, Bellvitge University Hospital, IDIBELL, Spain

Background & objectives: Immunotherapy targeting the programmed cell death-1 (PD-1) receptor and its cognate ligand (PD-L1) have shown promising results in several tumours. Our objective is to evaluate the expression of PD1 and PD-L1 in a series of anaplastic thyroid carcinomas (ATC).

Methods: PD1 (Cell Marque-NAT105) and PD-L1 (Ventana-SP142 and DAKO-22C3) immunohistochemical expression was assessed in 13 ATC. PD-1 staining was evaluated in inflammatory cells and PD-L1 in tumour cells and categorized according to the percentage of positive cells into: negative <1%, focal 1-25%, moderate 25-50%, diffuse >50%. The staining pattern (membranous, cytoplasmic and both) was also recorded in tumour cells.

Results: PD1 stained inflammatory cells in 9 cases (69%): 8 cases (89%) focally and 1 case (11%) diffusely. Membranous expression in tumour cells with PD-L1 (DAKO) was found in 11 cases (85%): 2 (18%) focally, 1 (9%) moderately and 8 (73%) diffusely. Conversely, PD-L1 (Ventana) staining in tumour cells was evidenced in 7 cases (54%): 6 cases (86%) focally and 1 case (14%) diffusely. Cytoplasmic stain was observed in 2 cases (28,5%), membranous in 2 cases (28,5%) and both in 3 cases (43%).

Conclusion: In our series a subset of ATC cases showed expression for PD-1 and PD-L1 in inflammatory and tumour cells respectively. The percentage of cases with tumour cell expression of PD-L1 differs among both clones. DAKO stained 85% of cases, most of them diffusely whereas Ventana 54% of cases with a predominant focal positivity. Finally, treatment options are lacking for ATC. Therefore, the use of PD1 and PD-L1 immunostaining as potential biomarker for immunotherapy in ATC deserve further research.

PS-08-014

Participation of proteins (Hsp90α) in the adaptive rearrangement of the pituitary-adrenal system of rats after long-term exposure to heavy metal salts

N. Hryntsova, S. Zaytseva, O. Romaniuk, L. Karpenko, A. Piddubnyi, D. Brusovtsov, N. Hyriavenko, A. Romaniuk*

*Sumy State University, Ukraine

Background & objectives: Pituitary-adrenal system takes an active part in regulating the body's adaptive capacity under the influence of exogenous factors. The morphological and immunohistochemical features of pituitary endocrinocytes and adrenal cortex under the adaptation to long-term exposure to heavy metals were studied.

Methods: The experiment was performed on 48 rats aged 5-6 months (2 control and 2 experimental groups). Experimental group animals received a combination of heavy metal salts: zinc/copper/iron/manganese/lead/chromium. Determination of heat shock protein marker 90 (Hsp90α) expression was performed using rabbit polyclonal antibodies to Hsp90α protein. The result was expressed as a percentage and evaluated on an accepted scale.

Results: Adaptive changes in the adenohypophyseal-adrenal system were characterized by an increase in the level of Hsp90α expression in the cytoplasm of 72-81% of adenohypophysis cells to moderate (2 points) and strongly positive (3 points) levels. Particularly high levels of expression to Hsp90α were found in the cytoplasm of cells located paravascularly. In contrast to the central link, in the adrenal cortex the areactivity of both the cytoplasm and the nuclei of corticocytes of all zones to Hsp90α has been established. In the glomerular and reticular zones, a moderately positive level of Hsp90α expression was found in vascular endotheliocytes, with special expression in the cortex's glomerular zone.

Conclusion: The pituitary gland showed a high level of expression to Hsp90α, which indicated a fairly high level of general restorative mechanisms of antistress protection. The reactivity of corticocytes of all adrenal zones to Hsp90α revealed a significant weakening of antiapoptotic and antistress protection in glandulocytes, weakening of control in cells regarding folding processes. Therefore, a 30-day adaptation period to a 90-day exposure to a combination of heavy metal salts is insufficient to fully restore homeostasis in the pituitary-adrenal system.

PS-08-015

Neuroendocrine neoplasia – relevant and interesting topics – a case-report and literature review

M. Souto Moura*, A. Varelas, M. Jácome

*Department of Pathology, IPO-Porto, Portugal

Background & objectives: Neuroendocrine neoplasms (NENs) are heterogeneous and ubiquitous. Globally their nomenclature is inconsistent and biological behaviour may be confusing.

Different treatment options can reduce grade and tumour load.

We aim to report a case and review the literature emphasizing these issues.

Methods: A 29-year-old woman was referred to our Institution (Feb/2019) after a Grade 2 (Ki-67: 4.6%) Neuroendocrine tumour (NET) hepatic metastasis was diagnosed. 68Ga-DOTA-NOC-PET revealed multiple foci of somatostatin receptor overexpression consistent with stage IV disease originating in the terminal ileum. Somatostatin analogues (SSAs) and shortly after lutetium-177 therapy were started. Re-evaluation showed a partial imagiologic response and surgical treatment was decided.

Results: Terminal ileocolectomy, hepatic metastasectomies and peritoneal implants removal was performed.

Ileocolectomy revealed a well-differentiated NET, Grade 1, based on the findings of less than 2 mitoses/2mm2 and a Ki-67 labelling of less than 3%, with lymphovascular and extensive perineural invasion. Liver and peritoneal specimens revealed metastasis of the neoplasia just described. Thereby, a downgrade of the tumour was verified, assumed to be related with the neoadjuvant therapy used.

Conclusion: Our case showed that even a well-differentiated NET can behave very aggressively. In particular, small intestine NETs often present with stage IV disease.

The 2018 WHO/IARC expert consensus proposal for NENs classification may reduce the inconsistencies and confusions across these neoplasms.

Several trials revealed an effect of SSAs and lutetium-177 (specially in combination) on tumour cell proliferation in somatostatin receptor-positive advanced NETs, enabling surgery, as in our case. Pathologists must be aware of the possibility of tumour downgrading following these therapies.

PS-08-016

“Plump pink” cells: an important morphological feature predictive of high-risk papillary thyroid microcarcinomas

E. Szasz*, A. Nechifor-Boilă, A. Borda

*Department of Histology, George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Târgu-Mureş, Romania

Background & objectives: In this study we aimed to investigate the importance of reporting high-risk morphological features, such as the presence of “plump pink” cells (PPCs), in a series of papillary thyroid microcarcinoma (PTMC) cases.

Methods: We re-analysed all consecutive PTMC cases, registered at the Department of Pathology, Târgu-Mureş Emergency County Hospital from 2003 to 2014. The following morphological features were noted, apart from the presence of PPC: tumour size, histological variant, tumour borders, stromal reaction, calcifications and intratumoral multinucleated giant cells. We also quantified the PPC component as diffuse (up to ≥20%) or focal (<20%).

Results: Our study included 206 PTMCs of which, 91 were ≥5mm and 115 <5mm PTMC. Polygonal, PPCs, characterized by abundant eosinophilic cytoplasm were found in 48/206 PTMCs, of which 34 presented a diffuse pattern and 14 focal plump cell component. The diffuse pattern was seen rather in large (≥5mm) (p=0.002) than in small (<5mm) PTMC, in which PPC were focally distributed. We have also shown that large PTMCs were significantly associated with other morphological features, predictive of high risk in PTMC: subcapsular location (p=0.0001), infiltrative tumour border (p=0.011), positive resection margins (p=0.022), tumour associated stromal reaction (fibrosis/desmoplasia/sclerosis) (p=0.0001), calcifications (p=0.007) and intratumoral multinucleated giant cells (p=0.0001).

Conclusion: In this study we have shown that PPCs, especially when diffusely distributed, are significantly associated with morphological features predictive of high-risk like in PTMC. This pattern is important to be mentioned in the histopathological report, as it could have an impact in predicting the tumour biological behaviour and could help the clinician in better guiding the patient’s management.

PS-08-017

Distribution of neuroendocrine neoplasms in a tertiary referral hospital in the Philippines

J. Uyboco*, M. Bonifacio, G.L. Pua

*St Luke's Medical Center - QC, Philippines

Background & objectives: Neuroendocrine neoplasms (“NENs”) have diverse presentations and outcomes. In Southeast Asia, the distribution of NENs is not yet studied. This study aims to describe the distribution and clinical features of NENs among patients at a tertiary hospital in the Philippines.

Methods: The study was an observational, cross-sectional study with retrospective review of patient records. Surgical pathology files from 2015 to 2020 were reviewed, and all histologically diagnosed neuroendocrine neoplasms were tallied and categorized by diagnosis, grade, stage, age, sex, primary tumour location, and hormone secretion. Statistical analysis was then performed using Microsoft Excel and R version 3.2.1.

Results: A total of 398 NEN cases were identified, accounting for approximately 0.5% of specimens received at the institution. NENs were most commonly diagnosed in the 60-79 year old age group, with a male:female ratio of 1.08.

Of the cases studied, 41.2% were well-differentiated neuroendocrine tumours ("NETs"), while 58.8% were malignant NENs.

The majority of cases were from the gastrointestinal tract (22.4%) and thoracic organs (20.1%). The individual organs in which NENs were most commonly diagnosed were the lungs (17.6%), followed by the rectum (11.8%), pituitary gland (8.8%), pancreas (6.5%) and uterine cervix (4.8%).

Abnormal hormone secretion was detected in NENs of the pituitary (71.4%), parathyroid (18.8%) and pancreas (15.4%).

Conclusion: The study revealed that the Philippine population demonstrates a distribution of neuroendocrine neoplasms by tumour site similar that seen in previous studies of East Asian and Pacific Islander populations. It remains to be seen if this is due to genetic similarities, environmental factors, screening and diagnosis practices, or some combination of the three.

We recommend further studies on the clinical presentation, staging, management and outcomes of local patients with neuroendocrine neoplasms.

PS-08-018

A cautionary tale of neuroendocrine differentiation in metastatic deposits – a two-case report

A. Varelas*, J. Costa, M. Souto Moura, F. Silva, M. Jácome

*Department of Pathology, IPO-Porto, Portugal

Background & objectives: A metastatic deposit with neuroendocrine phenotype in a patient with a previous diagnosis of carcinoma will not always correspond to an unknown primary. We present two such cases and the necessary additional workup.

Methods: Case1: a 68year-old male with a diagnosis of epidermoid carcinoma of the palatine tonsil in 2015 underwent biopsy for one of several hepatic nodules 3 months after. Case2: a 56year-old male underwent biopsy of a suspected recurrence/persistence of a previous cerebellar metastasis, 3 years after the initial diagnosis of stage IV lung adenocarcinoma with no EGFR-mutations nor ALK or ROS1 translocations.

Results: Both patients´ biopsies showed occupation by a small-cell phenotype carcinoma with neuroendocrine positivity. Clinical histories and slides of previous diagnosis were reviewed.

Case1: The patient underwent an hepatic metastasectomy, showing a small-cell neuroendocrine carcinoma. Upon revision, the previous tonsil biopsy presented an area with crushing artifacts and positivity for synaptophysin/p16, which was considered the primary origin of the metastasis.

Case2: the first cerebellar metastasis was consistent with non-small cell carcinoma, with solid and glandular areas. The patient had been submitted to multiple chemotherapy regimens and cranial radiotherapy prior to the last cerebellar biopsy showing small cell morphology.

Conclusion: We present two cases of neuroendocrine differentiation in metastasis. Case1 revealed to be from a combined neuroendocrine and non-neuroendocrine carcinoma of the tonsil. Case2 was explained as an histological transformation of non-small to small cell lung carcinoma; this has been reported in EGFR-mutated and, occasionally, non-mutated lung carcinomas. These illustrate possible scenarios in which the pathologist must consider the existence of an underdiagnosed neuroendocrine component in the primary tumour or the cytotoxic induction of a neuroendocrine clone after therapy.

PS-08-019

Determination of the management of neuroendocrine tumours in pathological anatomy services in Spain. Multicentre study

G.T. Vázquez Benítez*, M. Sampedro, J.L. Muñoz, J. Cubero, E. Triviño, M. del Olmo, J. Barrioso, J. Capdevilla

*Hospital Universitario HM Montepríncipe, Spain

Background & objectives: Neuroendocrine tumours (NETs) are a group of neoplasms that require a precise pathological assessment to be able to classify and adequately treat these patients.

Methods: An anonymous survey in digital format was designed in collaboration with the GETNE (Spanish Group of Neuroendocrine and Endocrine Tumours) Academy working group, made up of a multidisciplinary group that includes surgeons, nuclear physicians, endocrinologists, oncologists and pathologists. The survey included aspects related to clinical practice, and key elements in the anatomopathological diagnosis.

Results: 204 physicians responded to the surveys (45.6% surgery, 29.9% pathology, 8.8% oncology, 7.9% endocrinology, and 7.8% nuclear medicine). Some specialties had a higher prevalence of a reference person specialized in the management of NETs (p value <0.05). Regarding the assessment by pathological anatomy, 63.9% consider that the study of NETs sometimes represents a great diagnostic difficulty. In most centres, 51.2% do not have digital means to determine KI67 in a complementary way and 27.9% do not have IHC techniques to classify functioning NETs. 33.3% of pathological anatomy services always have the possibility of consulting cases with other centres and maintain correct communication with oncologists and surgeons (63.9% and 62.3% respectively)

Conclusion: The questions reflect that NETs are neoplasms that require specialized management since their diagnosis and classification is often not easy. A large part of the pathological anatomy services in Spain do not have some techniques that can serve as a complement in the diagnosis of NETs, but a large part have the possibility of consulting cases in other centres that have more experience as well as having the support from other specialties to improve the management of these neoplasms.

PS-08-020

A new pancreatic entity? Two novel cases of a intraductal papillary mucinous neoplasm (IPMN) mixed with a well-differentiated neuroendocrine tumour of the pancreas

G.T. Vázquez Benítez*, F.J. Salamanca, P. Gil, D. Klimstra

*Hospital Universitario HM Montepríncipe, Spain

Background & objectives: The neoplasms known as mixed neuroendocrine- nonneuroendocrine neoplasms (MiNENs), the non-neuroendocrine component of MiNENs is usually represented by an invasive carcinoma, but has not been describe the association with a intraductal papillary mucinous neoplasm

Methods: We find two patients; one of those is a 51-year-old male. Magnetic resonance of the abdomen, which was performed for the suspicion of hemochromatosis, discovered a 3 cm cystic lesion with septa in the body region of the pancreas and the other is a 56-year old female with an incidental cystic pancreatic lesion of 4,5 cm in an ultrasound image

Results: The both lesions were characterized by cystically dilated ducts lined by flat foveolar gastric-type epithelium, without relevant cytoarchitectural atypia but focally forming microscopic folds and subtle micropapillary projections. Therefore and accordingly with these features, the lesions were fundamentally a mixed-type IPMN with low-grade displasia, gastric foveolar subtype. Additionally, there were an underlying proliferation of round, monotonous cells with clear/foamy cytoplasm, stippled chromatin and single nucleoli. Immunohistochemically, these cells were positive for chromogranin and synaptophysin, supporting a neuroendocrine phenotype. The ki-67 was 2%. The mitotic rate in the neuroendocrine component was <1/10 high power fields. The findings in the neuroendocrine component supported a well-differentiated neuroendocrine tumour grade 1

Conclusion: The finding of a well differentiated neuroendocrine tumour associated with an IPMN is unusual and has not been described before. The association of an IPMN with a poorly differentiated neuroendocrine carcinoma has been described. This lesion may be conceptually considered a part of same spectrum of neoplasms known as MiNENs, but we do not regard MiNEN as a proper diagnostic term but rather a conceptual categorization to relate a somewhat diverse group neoplasms of with mixed differentiation.

PS-08-021

A glance over the clinicopathological features of parathyroid adenomas

O.C. Vita*, A. Dema, A. Văduva, A. Jurescu, A. Gheju, I. Mihai, R. Cornea, S. Tăban, C. Lăzureanu, M. Cornianu

*Department of Pathology, “Victor Babeș” University of Medicine and Pharmacy, Timișoara, Romania

Background & objectives: Parathyroid adenomas are benign neoplasms derived from parathyroid parenchymal cells and are the most common cause for primary hyperparathyroidism. In some cases, these tumours are a challenge for the pathologist. We aimed to assess clinicopathological profile of these tumours.

Methods: We performed a retrospective study on surgical resection specimens from patients with parathyroid adenomas operated at the "Pius Brinzeu" County Emergency Hospital Timișoara, Romania. Clinicopathological, serological - serum parathyroid hormone (PTH) and immunohistochemical data (antibodies anti-Ki67 and anti-Chromogranin A) were assessed.

Results: We identified 39 cases of parathyroid adenomas (32 women and 7 men, mean age 53). The most common site was in the inferior parathyroid glands (16 adenomas in right inferior gland, 10 adenomas in left inferior gland). A double adenoma was identified in the right thyroid lobe (RTL) and left inferior parathyroid gland, while an ectopic one in RTL was recorded. Morphologically, we identified 31/39 conventional adenomas, 2/39 water clear cell adenomas, 1/39 oxyphilic adenoma, 2/39 lipoadenomas and 3/39 atypical adenomas. 10/39 cases presented focal cytological atypia. Ki67 assay values were below 2% (higher value in atypical adenomas, but did not exceed 5%). All cases presented moderately elevated serum PTH.

Conclusion: Most parathyroid adenomas are solitary lesions with an easily recognizable, conventional morphology. The extent of increased mitotic activity raise the problem of differentiating adenomas from carcinomas, but the absence of vascular/capsular invasion certifies the benign nature of the lesion. Parathyroid adenomas arising in the thyroid gland can be difficult to differentiate from a thyroid neoplasms with follicular pattern. Elevated PTH levels are a supporting serological diagnostic element, while neuroendocrine differentiation markers are useful for the histological diagnosis of parathyroid adenomas.

PS-09 | Gynaecological Pathology Posters

PS-09-001

awareness of placental pathologic examination criteria and utilization of pathology reports among obstetricians

A. Alodaini*, Z. Almomen, G. Alkhalifah, L. Alafghani, N. Jalalah, N. Alsuwailem

*Imam Abdulrahman Bin Faisal University, Saudi Arabia

Background & objectives: Studies demonstrated low rates of placentas submitted to pathologic examination and poor utilization of pathology reports.Assess obstetricians’ awareness and utilization of the College of American Pathologists guidelines for placental pathologic examination and their understanding of reports terminology.

Methods: An anonymous survey was distributed to obstetricians working in different health institutes who are registered in Saudi Commission for Health Specialties’ (SCFHS) database. Statistical Package for Social Science (SPSS) software was used to examine the association between the level of training/practice and the surveyed elements as well as types of the institute and the surveyed elements.

Results: 288 responses were received. 34.4% of respondents were aware of CAP guidelines, most of which were practicing in governmental hospitals. While 18% of respondents routinely sent placentas for pathological examination, about 70% of them routinely review the pathology report and understand the used nomenclature; this was significantly higher in university hospital practitioners. Out of the three groups, the residents’ group was the least aware of the CAP guidelines and the least to review and understand pathology reports. In absence of CAP guidelines awareness, foetal anomalies were the most common indication used to send placentas for examination followed by medicolegal reasons and infections.

Conclusion: Placental pathologic examination was uniformly underutilized in surveyed practitioners. CAP guidelines were known to a minor subset within the surveyed participants. All this, combined with the variable understating of placental pathology reports, highlight the importance of raising awareness of CAP guidelines, formal placental pathology rotation for trainees and establishing a rapport between pathologists, and obstetricians to improve their understandings and use of the pathology reports.

PS-09-002

Accessory and cavitated uterine mass and the uterine rudimentary horn at an early reproductive age: differential diagnosis and management

A. Asaturova*, E. Khashchenko, E. Uvarova, E. Kalabuhova, V. Chuprynin, E. Allahverdieva, I. Luzhyna

*FSBI "National Medical Research Center for Obstetrics, Gynaecology and Perinatology after V.I. Kulakov" Ministry of Healthcare Russian Federation, Russia

Background & objectives:

ACUM (Accessory and Cavitated Uterine Mass) is a form of the Müllerian duct malformation, more common in adolescents and is an isolated additional uterine cavity in the normal uterus and optimal diagnostics and management strategies are yet to be developed.

Methods: We recruited 14 patients (average age 14 ± 1.66) who were subdivided into two groups: with malformation of the genital organs, ACUM (n=4) and with a doubling of the uterus with rudimentary functioning uterine horn (n=10). The diagnosis was made on the basis of anamnestic data, clinical and laboratory examinations and instrumental methods (ultrasound, MRI, laparoscopy and histological examination).

Results: Patients with ACUM revealed a non-communicating accessory uterine cavity with haemorrhagic contents, lined with a functioning endometrium, surrounded by a concentrically organized myometrium, while the main uterine cavity was of the correct shape. At the same time the closed functioning uterine rudiment was a separate formation more often at the edge of the uterus (MRI data). Histologically, ACUM was a node represented myometrium with endometrioid heterotopies. All patients underwent laparoscopic removal of ACUM and a functioning uterine horn followed by metroplasty. Average size for ACUM: 3,0(±0,72) х 2,3(±1,04) х 2,7(±0,79) cm, average size for functioning rudiments: 4,5(±0,87) х 3,1(±1,04) х 3,8(±1,17) cm (USD data)

Conclusion: The presented clinical observations emphasize the importance of imaging methods in the differential diagnosis of ACUM and uterine rudiment, of particular importance is the use of MRI and histology, which determines the main features that distinguish ACUM from the rudimentary uterine horn. The increased awareness of the ACUM diagnosis facilitates the selection of the optimal treatment and management of these patients as early as possible.

Funding: state assignment 18-A21 'The role of energy metabolism and immune defense disorders in the development of various forms of endometriosis...' (2021-2023)

PS-09-003

Anti-Müllerian hormone levels in adolescent girls with benign ovarian tumours

A. Asaturova*, E. Khashchenko, S. Kyurdzidi, A. Tregubova, Z. Kumykova, E. Uvarova, L. Ezhova, F. Mamedova

*FSBI "National Medical Research Center for Obstetrics, Gynaecology and Perinatology after V.I. Kulakov" Ministry of Healthcare Russian Federation, Russia

Background & objectives: Ovarian tumours in early reproductive cause the ovarian reserve reduction. Determination of the ovarian reserve with blood anti-Müllerian hormone (AMH) detection and its impact on benign ovarian neoplasm in adolescents requiring surgical treatment can help to reveal their prognostic value.

Methods: A retrospective study was conducted, 15 adolescent girls with benign ovarian tumours were included in the study. The average age of the patients was 14.9 (12-17) years. We analysed the data of anamnesis, clinical course, hormonal status, the level of tumour markers, the results of ultrasound examination of the ovaries, and pathomorphological analysis of the removed tumour.

Results: In mature teratomas (n = 11), the AMH level averaged 3.1 ± 1.45 ng / ml, in cystadenomas (n = 3) - 3.45 ± 3.18, and only with fibroma with a diameter of 4 cm was 10, 1 ng / ml. Regardless of the structure with a tumour size of 3-5 cm the AMH level was average 5.69 ± 1.40 ng/ml. Moreover, the AMH value was similar in girls with ovarian formations with a diameter of 6 to 19 cm (2.33-2.91 ng / ml). The thinned cortical layer in 6 out of 9 samples contained primordial and maturing follicles, even in cases of large ovarian tumours.

Conclusion: It is required to keep attention on the concentration of AMH when determining the further tactics of inpatient treatment of adolescents with benign ovarian tumours, even if the pathologist conclusion indicates the safety of the ovarian follicular apparatus in the damaged tissue.

Funding: State assignment 18-A21 'The role of energy metabolism and immune defense disorders in the pathogenesis of various forms of endometriosis...'

PS-09-004

Vulvar cancer: epidemiological, clinical and outcomes of 102 patients in the central region of Tunisia

D. Chiba*, N. Abdessayed, Z. Nfikha, M. Kouira, C. Zedini, T. Zahmoul, M. Mokni

*Department of Pathology, Farhat Hached University Hospital, Sousse, Tunisia

Background & objectives: Vulvar cancer is a rare gynaecologic malignancy. It is a pathology of women over 60y-o with a background of dystrophy and a mucous membrane oestrogen-deficient. Recently, it affects younger women due to the pathogenic-role of viral infectious agents such as the human-papilloma-virus, especially HPV16.

Methods: This is a retrospective cross-sectional descriptive study collected over a period of 20 years from January 1995 to December 2015. The study included all patients who were treated for primary malignant vulvar lesions in the obstetrics gynaecology department of Farhat Hached Hospital in Sousse, confirmed histologically on biopsy in the pathological anatomy department of the same hospital.

Results: A total of 102-patients were included with a mean-age of 66.45years (range 21 to 92 years). Only 12.7% of the patients were under 50y-o. The main reason for consultation was vulvar pruritus in 89.2% of cases, with an average delay of 15-months. The median tumour size was 3.75cm. A tumour biopsy was performed in all cases with the most frequent histological type was squamous cell carcinoma, representing 98%of cases. According to the FIGO classification, 65.68% (67) of patients were stage I-II, with more than50% stage I B (36/67). 34.3% (35) of patients were stage III or stage IV. Surgical treatment was performed in 94.68% of patients. The main objective of the surgery was to have free-surgical-margins over 8mm, objective achieved in 94.6%. 81.91% of the patients underwent inguinal lymph node dissection. The overall survival was 49.3% at 2 years and 28% at 5 years.

Conclusion: Vulvar cancer is a grave pathology, especially since it currently affects an increasingly young population since the incrimination of HPV in its genesis. Its treatment is heavy and burdened with a significant morbidity. However, its prognosis would be improved by an early diagnosis allowing a conservative surgical treatment. The prevention of this cancer passes by the exploration, the monitoring and the treatment of the chronic vulvar prurits, as well as the dystrophic and viral precursors.

PS-09-005

Role of hysteroscopy in the evaluation of tamoxifen induced endometrial abnormalities

D. Chiba*, Z. Nfikha, F. Hacheni, S. Smida, I. Bannour, S. Mestiri, N. Abdessayed, M. Mokni

*Department of Pathology, Farhat Hached University Hospital, Sousse, Tunisia

Background & objectives: Despite the large scientific evidence demonstrating that hysteroscopy examination is the gold standard of the management of abnormal uterine bleeding, data for accuracy of this procedure in symptomatic women under tamoxifen is less common.

Methods: the present study is a transversal retrospective descriptive study carried out in both gynaecological and pathological departments at Farhat Hached Hospital during a period of 10-years, from 1st-January-2006 to 31-December-2015. A total of 41-Tamoxifen-treated-patients with breast cancer who presented with abnormal -uterine-bleeding were enrolled. The mean age was 52,7-years at diagnosis. The mean period of taking tamoxifen was 31,8 +/– 14,6months.

Results: The mean cumulative dose of Tamoxifen was 19,1g. The Median endometrial thickness on transvaginal ultrasonography examination was 11mm. Hysteroscopy was indicated for abnormal-uterine-bleeding with thickened-endometrium in most of the cases (83,7%) and showed that atrophy was the most common finding (26%). Abnormal-hysteroscopy-findings were dominated by polyps and hyperplasia that were found in 27,9% and 25,6% of the cases respectively. Hysterescopic appearance suggestive of malignancy was found in one case (2,3%). Curettage of the uterine cavity was performed for the majority of the patients (95,3%), and targeted biopsies were required in two cases. Endometrial sampling yielded insufficient tissue in 18,6% of cases.

Histological examination exhibited benign findings for the all patients except one for whom subsequent hysterectomy specimens that concluded to an atypical complex hyperplasia.

Conclusion: For distinguishing endometrial abnormalities from normal findings, hysteroscopy had an overall accuracy of 80%. For the diagnosis of polyps, leiomyoma and hyperplasia, hysteroscopy had an accuracy of 94.28%, 91.42% and 74.28% respectively.

Hysteroscopy represents an accurate and non-invasive method for the assessment of endometrium, and should be mandatory for patients under tamoxifen any time AUB occurs. The benefits and risks of prophylactic use of levonorgesterel intrauterine system are still to be determined.

PS-09-007

Exploring differentially methylated genes in vulvar squamous cell carcinoma

S. Dasgupta*, P.C. Ewing-Graham, S.M. Swagemakers, T.P. van den Bosch, H.C. van Doorn, P.J. van der Spek, S. Koljenovic, F. van Kemenade

*Erasmus MC, The Netherlands

Background & objectives: Aberrations in DNA-methylation are known to play a role in carcinogenesis, and methylation profiling has enabled the identification of biomarkers of potential clinical interest for several cancers. For vulvar squamous cell carcinoma (VSCC) however, methylation profiling remains an under-studied area.

Methods: We sought to identify differentially methylated genes (DMGs) in VSCC, by performing Infinium MethylationEPIC BeadChip (Illumina) array sequencing, on a set of primary VSCC (n = 18), and normal vulvar tissue from women with no history of vulvar (pre)malignancies (n = 6). Immunohistochemistry was performed with p16 and p53 to categorize the VSCCs as HPV-associated or HPV-independent.

Results: Using false-discovery rate of 0.05 and beta-difference (Δβ) of ± 0.5 as cut-offs, we identified 387 probes located in the CpG islands that were differentially methylated in VSCC. These probes corresponds to 199 DMGs (195 hyper-methylated, 4 hypo-methylated). The majority of the hyper-methylated genes were found to be involved in transcription regulator activity, indicating that disruption of this process plays a role in VSCC development. The majority of VSCCs harboured amplifications of chromosomes 3, 9, and 10. By integrating methylation and copy number variation analyses, 5 DMGs were identified, namely, APLP2, ARHGEF12, CSGALNACT1, GRM7, and PRICKLE2-AS1, which harboured deletion in one allele and hypermethylation in another allele.

Conclusion: We identified a set of DMGs in VSCC in this study with a view to promote hypothesis-generation, and to provide a resource for future investigations to evaluate the diagnostic, prognostic, predictive, or therapeutic potential of these methylation-based bio-markers. Prognostic relevance of these DMGs deserves further exploration in larger cohorts of VSCC and its precursor lesion, vulvar intraepithelial neoplasia (VIN).

PS-09-008

Validation of MODEPLEX technology for the determination of POLE hotspot mutations in endometrial carcinoma samples

E. Dorca*, A. Velasco, D. Cuevas, M. Vaquero, S. Gatius, E. Guerra, A. Rodríguez Vázquez, A. Vidal, X. Matias-Guiu

*Hospital Universitari de Bellvitge-Idibell, Hospitalet de Llobregat, Spain

Background & objectives: Molecular classification of endometrial cancer based on TCGA data recognizes 4 subtypes: 1)CNH, 2)Hypermutated, 3)CNL and 4)Ultramutated (POLE mutated). This study intends to explore the diagnostic performance of a novel technology (MODAPLEX) to study POLE mutations in endometrial carcinoma samples.

Methods: 96 endometrial cancers samples with available histological/molecular classification, were selected. For each case a tumoral block was chosen, obtaining eight sections of 10 μm thickness and subsequently isolating DNA with “Cobas DNA Sample Preparation Kit”. DNA concentration was measured by Qubit, excluding those cases with a concentration under 10 ng/μl. Positive results were reconfirmed using Sanger sequencing.

Results: 94 samples were submitted to the test, discarding 20 of them for an invalid result. Among the final 74 samples, 15 were POLE mutated, 18 CNL, 25 CNH and 16 MSI. MODAPLEX identified 13 samples with mutations on POLE, which were: V411L,P286R,S297F,A456P and L424V. All these mutations were located in the exonuclease domain and had a functional impact on the protein. All the reported mutations by MODAPLEX, were afterwards confirmed by Sanger sequencing. Two cases previously classified as POLE were not identified by the test, but repeatedly confirmed by Sanger. These two cases harboured A456V and A465T mutations, described as uncommon and whose primers were not covered by the kit.

Conclusion: MODAPLEX is a promising technology still in development that allows the determination of the main “Hotspot” mutations in POLE gene in a fast, practical and efficient way. Following a Single-Gene approach and in this clinical context, this technology could compete with Sanger sequencing for the study of POLE mutations.

This test could emerge as a valid and fast alternative to Next – Generation Sequencing, especially in those centres where they do not have access to massive sequencing techniques.

PS-09-009

NFIB rearrangement and MYB-NFIB fusion are infrequent events in vulvar adenoid cystic carcinoma

D. Doutel*, D. Venda, F. Silva, C. Martins, A. Félix, J. Ferreira

*Instituto Português de Oncologia de Lisboa Francisco Gentil, Portugal

Background & objectives: MYB/MYBL1-NFIB fusions are driver events in adenoid cystic carcinomas (ACC). MYB rearrangement and MYB-NFIB fusion have been reported to occur in ~60 and 30% of vulvar ACCs, respectively. We aim to access the prevalence of NFIB rearrangement and MYB-NFIB fusion.

Methods: We retrieved four vulvar ACCs from our institution’s archives diagnosed between 1994 and 2019 for which FFPE material was available. All histological slides and medical records were reviewed.

For detection of gene rearrangements by fluorescence in situ hybridization (FISH) two strategies were applied: 1) break-apart probes for MYB, MYBL1 and NFIB genes and 2) dual colour probes for MYB-NFIB fusion.

Results: Patients were 41-70 years old at the time of diagnosis. All cases were treated by surgery alone at presentation, 3 of which suffered local recurrence. The diagnosis of adenoid cystic carcinoma was confirmed in all cases, none with a high-grade component. All patients were alive and disease free at the time of the last follow-up appointment (median: 102,5 months).

MYB rearrangement was detected in 3/4 cases, including one with concurrent MYB amplification. No MYBL1 nor NFIB rearrangements were found. MYB-NFIB fusion was absent in all four cases. One of our cases, despite having a classical ACC morphology, did not have NFIB, MYB or MYBL1 rearrangements, or MYB-NFIB fusion.

Conclusion: We report a lower rate of NFIB rearrangement and MYB-NFIB fusion than expected. In keeping with the other studies performed in this anatomical location, the prevalence of NFIB rearrangement and MYB-NFIB fusion seems to be lower in the vulva than elsewhere. Although MYB activation occurs in the majority of vulvar ACC, it is likely due to other mechanisms yet to be unravelled.

PS-09-010

HER2/neu expression in patients with primary uterine endometrial carcinomas in Batangas Medical Center, Philippines

D.A.R. Bacong, G.A. Espiritu*

*Centro Escolar University, Philippines

Background & objectives: Uterine cancer is the eighth leading cancer among women with an estimated age-standardized Philippine incidence rate of 5.6 per 100,000. To aid in the prognostication and management of endometrial cancers, expression of HER2/neu in Filipinos with endometrial cancer was determined.

Methods: Sixty-seven cases out of all 71 resection specimens with endometrial cancer, from 2017 to 2019, were included in the study. Exclusion of the 4 cases was due to unavailability of paraffin blocks. Histological section was taken for immunohistochemical staining with HER2/neu. Previously proposed HER2 testing algorithm for endometrial carcinoma (EC), based on the modified 2007 ASCO/CAP breast criteria, was used.

Results: Eighty-six percent of the patients were 45 years and older. Ninety-five percent were of endometrioid histologic type, 2 (2.98%) cases were serous, and 1 (1.49%) case was mixed Mullerian tumour. Lymph node metastasis was present in 6.0% of cases. Most of the cases (65.67%) belonged to FIGO Stage I. HER2/neu was positive (3+) in 27.3% (3/11) of endometrioid grade 3, 14.3% (3/21) of endometrioid grade 2, and 6.1% (2/33) of endometrioid grade 1. Among the two cases with serous EC, one was positive while the other was negative. The single case of mixed Mullerian tumour was positive for HER2/neu. HER2/neu was either negative or equivocal in cases with node metastasis.

Conclusion: Although most of the HER/neu positive cases in this study were seen in tumours with higher histologic grade, Fisher Freeman Halton test showed no sufficient evidence to say that age, lymph node involvement, FIGO grading and cancer staging were associated with HER2/neu expression. Since literatures show HER2/neu had significant association on prognosis, overall survival, and has potential for targeted therapy and/or as adjunct to chemotherapy, a larger, multicentre study is warranted.

PS-09-011

Nuclear beta-catenin expression - a prognostic marker for endometrial carcinomas

A. Evsei*, A. Birceanu-Corobea, M. Sajin, N. Copca

*Saint Mary Clinical Hospital, Bucharest, Romania

Background & objectives: Numerous studies have shown that immunohistochemical nuclear beta-catenin expression in endometrial carcinoma (EC) is a successful substitute for CTNNB1 exon 3 mutation. Our purpose for this study was to evaluate the nuclear beta-catenin expression in 50 cases of endometrial carcinoma.

Methods: We tested immunohistochemical nuclear beta-catenin expression in 50 cases of endometrial carcinomas in Romanian female patients. We also performed statistical correlations between this marker and various parameters (histopathological, immunohistochemical etc.). Also, we analysed what molecular subgroup of endometrial carcinomas (MSS, MSI, p53wt, p53abn) showed the most frequent cases with beta-catenin expression.

Results: Our study revealed that ECs with nuclear beta-catenin positivity was observed in cases with higher FIGO grade (p=0.02), in endometrioid carcinomas (p=0.04) and in cases with lymphovascular invasion (p=0.05). ER and PR were frequently expressed in the positive beta-catenin subgroup (p=0.03, p=0.02). Our results show that ECs which express nuclear beta-catenin correlate with parameters that are already established as unfavourable.

Conclusion: Our struggle for affordable prognostic markers is a continuous battle. The immunohistochemical beta-catenin nuclear expression is an excellent replacement for CTNNBB1 exon 3 mutation in ECs and predicts prognosis in certain cases of ECs. We believe that future research will include this marker as part of the routine immunohistochemical panel for ECs.

PS-09-012

Rhabdomyoblastic differentiation in uterine carcinosarcoma: impact on survival and recurrence

A. Fitouri*, G. Sahraoui, L. Charfi, N. Boujelbene, M. Slimane, I. Abbes, K. Mrad, R. Doghri

*Pathology Department, Rabta Hospital, Tunisia

Background & objectives: Uterine carcinosarcomas (UCS) are characterized by a carcinomatous and sarcomatous contingent. Heterologous mesenchymal components, most frequently show rhabdomyoblastic or chondroid differentiation. The aim of our study was to determine the impact of rhabdomyoblastic differentiation on survival and recurrence.

Methods: Study was retrospective, covering 52 patients operated by hysterectomy and whose diagnosis of UCS was confirmed on an operative specimen at the anatomy and pathological cytology department of the Salah Azaïez institute in Tunis from 2018 to 2000. Statistical analysis was done using the Kaplan-Meier method and the Log-Rank test in univariate analysis (The statistical significance level was ≤ 0.05).

Results: For the 52 patients with UCS, rhabdomyoblastic differentiation was present in 22 cases (42.3%) and absent in 30 cases (57.7%).

The overall survival rate at 1 year, 3 years and 5 years for patients who presented rhabdomyoblastic differentiation were 56%, 27% and 18% compared to 75%, 59% and 47% for those who did not present this differentiation. This difference was statistically significant (p = 0.0193).

The recurrence-free survival rate at 1 year, 3 years and 5 years for patients who presented rhabdomyoblastic differentiation were 45%, 31% and 30% compared to 71%, 53% and 43% for those who did not present this differentiation. This difference was statistically significant (p = 0.05).

Conclusion: UCS are high grade tumour, characterized by a poor 5-year overall survival rate (overall <35%). The role of heterologous sarcomatous elements as a prognostic factor has been widely discussed with discrepant results in different series. Whereas, like our study, the presence of rhabdomyoblastic differentiation is a factor of poor prognosis correlated, in univariate analysis, with a bad overall survival. It is also correlated with a bad recurrence-free survival.

PS-09-013

Comparison of endometrial biopsy and postoperative hysterectomy specimen findings in patients with uterine carcinosarcoma

A. Fitouri*, G. Sahraoui, L. Charfi, M. Slimane, N. Boujelbene, I. Abbes, K. Mrad, R. Doghri

*Pathology Department, Rabta Hospital, Tunisia

Background & objectives: Uterine carcinosarcomas (UCS) are biphasic tumours which diagnosis can be made on biopsy or surgical specimen.

The aim of study was to assess concordance between preoperative endometrial sampling and microscopic examination of hysterectomy specimens in patients finally diagnosed with UCS.

Methods: We analysed a group of 43 patients who had a biopsy and whose diagnosis of UCS was confirmed on operative specimen at the pathological anatomy and cytology department of the Salah Azaïez institute in Tunis, over a period of 19 years (from 2018 to 2000).

Results: Endometrial biopsy was performed in 43 patients. It made it possible to make the exact diagnosis of UCS in 20 cases (46.5%). In the 23 other cases (53.5%), the diagnosis was corrected postoperatively. The diagnoses mentioned were: endometrioid adenocarcinoma in 14 cases (32.6%), sarcoma in two cases (4.7%), undifferentiated tumour in one case (2.3%), undifferentiated carcinoma in one case (2.3%), serous carcinoma in one case (2.3%), adenosarcoma in one case (2.3%) and the result was non-contributory in three cases (7%).

Conclusion: In endometrial cancer, our findings demonstrate a low level of concordance between the histological diagnosis on endometrial curettage and at hysterectomy.

The sensitivity of this biopsy to detect sarcomatous elements is lower than that of carcinomatous elements. Many studies conclude that endometrial sampling is less precise in predicting the final histological diagnosis of the sarcomatous component than the carcinomatous component. Indeed, the diagnosis of UCS is often made on the surgical specimen.

PS-09-014

Complete hydatidiform mole with mosaic histology: a study of 10 cases with immunohistochemistry

M. Fukunaga*

*Shin-Yurigaoka General Hospital, Japan

Background & objectives: Complete moles (CM) with mosaic histology may pose a diagnostic challenge. Differential diagnosis is very important for patient management. The objective is to clarify histologic and immunohistochemical features and its histogenesis.

Methods: Ten cases of CM with mosaic histology in the first trimester were retrieved, and their initial diagnoses included CM (3 cases), a twin placenta with CM (2), CM with mosaic histology (2), PM (2), and hydropic abortion with trophoblastic hyperplasia (1). They were analysed with immunostaining of p57 (Kip2) and TSSC3, which are products of paternally imprinted, maternally expressed genes.

Results: Histologically, 5 cases had both CM and placental mesenchymal dysplasia (PMD) components. The 5 remaining cases had CM and non-PMD components. Cytotrophoblasts and stromal cells of CM components were negative for p57. Cytotrophoblasts and stromal cells of non-PMD components expressed p57. In PMD components, cytotrophoblasts were positive for p57 and TSSC3, and stromal cells were negative for p57, indicating that the stromal cells were androgenetic, and the cytotrophoblasts were biparental.

Conclusion: The findings support the hypothesis that the misexpression of p57 and TSSC3 is involved in abnormal development of androgenic CM. CM with mosaic histology can be classified into two groups; CM with PMD components and CM with non-PMD components. None of the cases was CM with twin, but rather CM with androgenic/biparental chimera or mosaic molar gestation and PMD. Immunohistochemistry of p57 and TSSC3 can be a useful screening tool for cytogenetic analyses of CM with mosaic histology.

PS-09-015

Mast cell microenvironment in smooth muscle tumours of the gynaecologic tract

T. Georgescu*, A.C. Lisievici, S. Barbu, O. Toader, D. Cretoiu, M. Sajin, N. Suciu

*Carol Davila University of Medicine and Pharmacy Bucharest, Romania

Background & objectives: The scientific literature states that smooth muscle tumours of the gynaecological tract harbour a variable number of mast cells, similar to neural tumours. Several studies have reported a higher number of mast cells in atypical leiomyomas, compared to leiomyosarcomas.

Methods: A total of 98 smooth muscle tumours have been diagnosed in our laboratory during a period of 4 months, including 78 leiomyomas, 18 atypical leiomyomas and 2 leiomyosarcomas. The number of mast cells was evaluated per 10 HPF on both Hematoxylin Eosin and Toluidin Blue stains, and subsequently correlated with the presence of atypia, necrosis and mitotic index.

Results: The total number of mast cells varied from 0 to 156 per 10 HPF, with a mean of 28. Tumour size correlated best with a high number of mast cells. All leiomyomas larger than 10 cm had more than 30 mast cells / 10 HPF. Apoplectic leiomyomas had a mean of 48 mast cells / 10 HPF, with more than 70% of cases featuring at least 40 mast cells / 10 HPF. High numbers of mast cells were also observed in cellular leiomyomas (45) and mitotically active leiomyomas (33). Less than 10 mast cells / 10 HPF were observed in epithelioid leiomyomas and in leiomyosarcoma.

Conclusion: The increased number of mast cells encountered in large leiomyomas, apoplectic and cellular leiomyomas can serve as a reassuring criterion, aiding in the differential diagnosis with leiomyosarcoma. Ordinary leiomyomas feature a low number of mast cells, 76% of them having less than 10 mast cells / 10 HPF.

PS-09-016

Choriocarcinoma in South African women: analysis of a series with genotyping

J. Goedhals*, J. Oosthuizen, A. de Kock, M. Theron

*NHLS and UFS, South Africa

Background & objectives: Choriocarcinomas can be either gestational, arising from a previous pregnancy, or non-gestational. The prognosis and treatment differ and correct categorisation is important. Genotyping can be used to make this distinction, but this technique has not yet been used in Africa.

Methods: In this study, we genotyped 20 choriocarcinomas and 6 control cases of complete hydatidiform mole (CHM) using a short tandem repeat multiplex polymerase chain reaction (PCR) assay for 15 loci and a sex marker, amelogenin.

Results: All the patients were of African descent. Amplification failed in two cases and these were excluded from the study. Of the remaining 18 choriocarcinoma cases, 17 were gestational and one was non-gestational. Sixteen of the gestational cases were purely androgenetic/homozygous XX compatible with a previous CHM, while one arose from a previous normal pregnancy. In addition, a rare variant allelic repeat, 22.2 at locus FGA, was identified in one case. This variant has a frequency of 0.0026 in the South African population.

Conclusion: In this study, 88.9% of the choriocarcinomas were gestational arising from a previous CHM, which is in keeping with previous international studies. Although molecular genotyping is not required in all cases of choriocarcinoma as the majority are gestational, molecular genotyping can be useful in cases that do not respond to first-line treatment and cases where the clinical history is suggestive of a non-gestational tumour so that the appropriate treatment can be implemented.

Funding: Funding obtained from the National Health Laboratory Service Research Trust

PS-09-017

PTEN mutation enhances insulin-like growth factor 1 receptor expression in endometrial cancer

Z. Greally*, P. Lewitowicz, O. Adamczyk-Gruszka, M. Wawszczak, A. Filipiak, W. Lewitowicz, E. O'Regan

*Student Science Club at Collegium Medium, Jan Kochanowski University, Poland

Background & objectives: PTEN inhibits the Akt signalling pathway thus plays an important role in regulating cellular behaviors.

We investigated if PTEN (which seems to act as a negative regulator of IGF1R and IGFR2) enhances proliferation and the inhibition of apoptosis if mutated.

Methods: We analysed 102 cases of endometrial cancer treated between 2005- 2020. DNA extracted from 102 clinical specimens of endometrial cancer FFPE. Sixty-eight DNA samples were successfully processed with the AmpliSeq for Illumina Cancer Hotspot Panel Cancer according to manufacturer’s manual. The analysis included hotspot regions of 50 genes with known associations to cancer. The data was analysed for sequencing coverage.

Results: Our initial data showed IGF-1R overexpression in 78% of samples. We observed PTEN mutation in 49% and PIK3CA in 35% of cases. The preliminary statistics suggests a strong correlation PTEN silencing with IGF1R overexpression (p<0.05). Interestingly, we have not noted the same with PIK3CA and KRAS mutation (p>0.05)

Conclusion: Our row data are still under biostatistics, but first the insight allows us to connect IGFR1R overexpression in endometrial cancer with the inhibition of PTEN activity.

PS-09-018

HOXA11 Receptors as an additional marker of implantation in assisted reproductive technology programs (ART)

E. Kazachkov*, E. Chukhnina, E. Voropaeva, E. Kazachkova, D. Voropaev, A. Koshkina

*South Ural State Medical University, Russia

Background & objectives: HOXА genes and the proteins they encode are key regulators of endometrial reception. The aim of the study was to evaluate the effect of HOXA10 and HOXA11 expression levels in the stroma on the results of ART programs.

Methods: A prospective cohort study of IVF outcomes was performed in 68 women of advanced reproductive age with tubal-peritoneal infertility. An endometrial pipe-biopsy was taken during the supposed implantation window. The endometrial samples were formalin-fixed and embedded in paraffin. For immunohistochemistry, rabbit polyclonal HOXA10 аnd HOXA11 receptor antibodies were used. The percentage of HOXA10 and HOXA11-positive stromal cells was calculated.

Results: The threshold value of HOX11 expression in endometrial stromal cells at the cut-off point was 6.14%. When the threshold parameter is equal to or less than 6.14%, the endometrium is characterized as receptive, favourable for implantation, with a value of more than 6.14% of the threshold parameter unfavourable for implantation. The area under the ROC curve corresponding to the relationship between implantation prognosis and HOXA11 expression in endometrial stroma cells was 0.784=0.058; 95% CI: 0.672-0.897 (p=0.000). The sensitivity and specificity of the method were 80% and 73%. There were no significant differences in the expression of HOXA10 in endometrial stromal cells at different outcomes of ART programs.

Conclusion: The results of the study allow us to expand the range of markers of endometrial receptivity in infertility of tubal origin in women of older reproductive age. The revealed reference value of HOXA 11 expression in the endometrial stroma in the" implantation window " opens up prospects for the development of new approaches to the pathogenetic preparation of the uterine mucosa for blastocyst implantation.

Funding: The research was funded by RFBR and Chelyabinsk Region, project number 20-415-740014.

PS-09-019

Oxidative stress influence and ROS up-regulation on umbilical cord cytokines and their role in inflammatory complications after spontaneous preterm birth

I. Koleva*, M. Angelova, G. Nikolova, Y. Karamalakova

*Medical Faculty, Trakia University, Bulgaria

Background & objectives: The aim of this research was to examine the oxidative stress (OS) biomarkers, reactive oxygen species (ROS) up-regulation and inflammatory cytokines complications associated with changes in the endogenous antioxidant defense (EAD) in the umbilical cord, after spontaneous preterm birth (sPTB).

Methods: We assessed OS biomarkers- ascorbate, superoxide-anion, nitro radicals and ROS up-regulation in the umbilical cord in 101 women with sPTB. OS were measured by EPR spin-trapping spectroscopy in real time. The EAD levels- superoxide dismutase (SOD), catalase (CAT), glutation peroxidase (GSH), total antioxidant capacity (TAC) and interleukins (IL)-IL-6 and IL-17 inflammatory complications were measured by enzyme-linked immunosorbent assay (ELISA).

Results: The prospective case-control study was conducted at UMBAL, Stara Zagora, Bulgaria (2017-2020) and determined in two groups: n1=100 sPTB, cardiotocography confirmed for >32 g.a.; n2=100 healthy pregnant, with a registered singleton pregnancy, at 37-39+6 g.a. gave birth on the term (BT). The two-fold decrease (p> 0.05, t-test) expression of OS biomarkers (i.e. ascorbate radicals, superoxide radicals, nitric oxide, SOD, CAT, GSH, TAC); significant two-fold increase of ROS concentration (R = 0.958, p<0.05, t-test) and inflammatory factors levels, i.e. IL-6 (p<0.003, t-test) and IL-17 (p<0.005, t-test) were registered in umbilical cord homogenates in sPTB patients, compared to BT.

Conclusion: Generally, our findings suggest that OS involves many signalling molecules in the umbilical cord of sPTB, which are regulated in a dynamics manner. The additional sPTB mechanisms caused increased OS, ROS overproduction, and IL-6 and IL-17 inflammatory complications, which in turn leads to endogenous antioxidant system failure in the umbilical cord in preterm infants and elevated infant mortality.

Funding: The study was supported by Ph.D. program of Dr. Iliana Koleva- Kerkelia and scientific project 1/2020 of Medical Faculty, Trakia University, Bulgaria.

PS-09-020

Expression of PTEN in cervical lesions and its correlation with adhesion proteins

D. Koumoundourou*, G. Michail, G. Androutsopoulos, P. Ravazoula

*Patras University Hospital Pathology Department, Greece

Background & objectives: The role of PTEN and adhesion molecules in cervical neoplasia isn't well established.

The purpose of our study was the assessment of PTEN, B-catenin and E-cadhenin expression in cervical lesions and the evaluation of their potential role in cervical carcinogenesis.

Methods: 47 low and high grade cervical dysplasia specimens (CINI-II-III) and 10 specimens of invasive squamous cervical carcinomas were used and the proteins’ expression was evaluated using immunohistochemistry. Statistical analysis was performed implementing SPSS16 for windows.

Results: PTEN and E-cadherin expression was found decreased in CIN III and invasive carcinomas (p=0,022) while a strong association was also found between PTEN and E-cadherin immunopositivity (p=0,011). The expression of B-catenin was strongly correlated with E-cadherin’s immunostaining (p=0,027)

Conclusion: E-cadherin and β-catenin seem to correlate with each other, and their expression is probably involved in the development of cervical lesions. Furthermore, PTEN loss represents a crucial event in malignant transformation procedure; however, its correlation with the adhesion proteins deserves further investigation.

PS-09-021

Serous cell differentiation as a marker of neoplastic transformation in patients with ovarian endometrioid cysts

L. Mikhaleva*, O. Patsap, T. Bezuglova, A. Davydov, G. Aliev

*FSBI RIHM, Russia

Background & objectives: Endometriosis ranges up to 15% in women and is one of causes of the infertility. Many theories highlight pathogenesis of the endometriosis and endometriosis-associated tumours but none of them can explain its ability to neoplastic transformation and associated serum biomarkers.

Methods: This study was conducted on surgical specimens from ovarian endometrioid cysts (OEC) and the ovarian tumours obtained after surgical operation from 117 patients. Normal level of serum CA-125 was assumed to be up to 35 IU/ml. Immunohistochemical study of WT1, p53 antibodies was performed.

Results: The results revealed a direct correlation between the level of serum CA-125 and the appearing of serous IHC-phenotype in epithelial OEC cells with WT1 expression (Pearson r= 0.84, p<0.0001) and the p53 expression in the OEC epithelium (Pearson r= 0.81, p<0.0001) as well as direct correlation was found when studying the relationship between WT1 and p53 expression in OEC epithelium (Pearson r= 0.79, p<0.0001). A moderate direct relationship was found between the OEC size and the WT1 and p53 expression (Spearman r = 0,5 and 0,6 resp.), along with a moderate inverse relationship between BMI and the level of p53 expression (Spearman r = - 0,57 and - 0,6 resp.).

Conclusion: This research revealed the changes in OEC epithelium with serous epithelial type IHC-phenotype that were associated with an extensive rise in the serum biomarker CA-125 level, that could indicate the early neoplastic transformation of OEC.

PS-09-022

Parietal endometriosis on caesarean section scar: study of 8 cases

Z. Nfikha*, S. Mestiri, S. Smida, B. Bannour, D. Chiba, S. Chaieb, M. Mokni

*Department of Pathology, Farhat Hached Hospital, Tunisia

Background & objectives: Parietal endometriosis is a rare pathology and represents 1 to 2 % of cases of extragenital endometriosis. It can occur on all scars, most often during surgery with hysterotomy, and is due to the implantation of endometrium in the scar.

Methods: The retrospective study concerns all the cases of parietal endometriosis taken in charge during one year in the Farhat Hached gynaeco-obstetrical service from January 1, 2018 to December 1, 2019.

Results: Six patients were operated during this period. The average age was 34 years. All patients had at least one history of caesarean section. The interval between the operation and the appearance of the first symptoms was on average four years. Only 50% of the patients presented a typical clinical picture with pain according to the menstrual cycle. The average size of the nodules was 2 cm. The diagnosis of parietal endometriosis was suspected before treatment in 100% of cases. The treatment was surgical, involving removal of the nodule. In 62.5% of cases the lesion was preaponeurotic. There were no complications except for a single case of homolateral recurrence.

Conclusion: Parietal cicatricial endometriosis is a rare pathology but its diagnosis must be evoked in particular in women who have undergone open gynaecological or obstetrical surgery and who present pain associated or not with menstrual disorders. The treatment is mainly surgical.

PS-09-023

Expression RIP3, a molecular switch for necroptosis and inflammation, in cases of placenta accreta

N. Nizyaeva*, A. Mikheeva, O. Lisitsyna, V. Mukhametzyanov, T. Sukhacheva, R. Serov, R. Shmakov, G. Sukhikh

*National Medical Research Center for Obstetrics, Gynaecology and Perinatology, Moscow, Russia

Background & objectives: Recently, there has been an increase in the incidence (1:500) of the of placenta accretа spectrum (PAS). However, the pathogenic mechanisms of placenta accreta aren't clear. The receptor-interacting protein kinase 3 has emerged as a critical regulator of programmed necrosis.

Methods: The study included 63 patients of reproductive age (mean 34,64±3,69 y.y.), after caesarean section at 34-36 gestation weeks with PAS. We performed histological (H&E, methylene blue) and immunohistochemical studies to primary antibody (1:500; Abcam) on paraffin- and epon-araldite-embedded preparations of 63 myometrium samples (accreta–36, 19–increta, 8–percreta), taken after caesarean section. Сontrol group were 8 myometrium samples from women without PAS.

Results: As a results of the histologic examination reflected dystrophic damage and partial membrane bubbling, cytoplasm fragmentation and condensation of chromatin of some smooth muscle cells and fibrоblasts in myometrium samples in cases of PAS group comparison to the control group (p<0,05). Immunohistochemical study showed significant increased RIP3 cytoplasmic expression in smooth muscle cells, fibroblasts, endothelium of blood vessels, and especially decidual cells than in the control group (p<0,05). In the sites of necrosis associated with placenta increta, the expression of RIP3 was absent.

Conclusion: Thus, disturbances of expression RIP3 the mechanisms of necroapoptosis in PAS are activated, which probably facilitates the placenta invasion into the myometrium.

Funding: This study is supported by State Assignment №25-А19.

PS-09-024

PTEN mutation landscape in endometrial cancer

E. O'Regan*, Z. Greally, W. Lewitowicz, P. Lewitowicz, O. Adamczyk-Gruszka, M. Wawszczak, A. Filipiak

*Jan Kochanowski Medical School, Poland

Background & objectives: PTEN gene (tumour suppressor gene).PTEN protein maintains the balance of the PI3K/AKT pathway. The loss of PTEN gene function increases rate of occurrence of aggressive metastatic disease, it can be used as a biomarker for prognosis in distinguishing indolent tumours from aggressive.

Methods: we analysed 102 cases of endometrial cancer from 2005-2020 their complete clinical information, chemotherapy regiments and recurrence free survival was tabulated. 68 DNA samples (67%) were successfully processed with AmpliSeq for Illumina Cancer Hotspot Panel Cancer (Illumina Inc, San Diego, California). The analysis included hotspot regions of 50 genes with known cancer associations. Analysis for sequencing coverage and variant frequency cut-off occurred

Results: In the group that was studied we observed a 49% frequency of PTEN mutations. There was a large mutational heterogeneity noted. In comparison to the Cosmic Database the frequency of nonsense, missense and frameshift insertion were on a similar level, however the frequency of frameshift deletion was much higher reaching 30% compared to 15%. On the other hand, PIK3CA, KRAS, FGFR2, CTNNB1, FBXW7 genes have shown great homogeneity with almost only missense type mutations. The TP53 gene mutation was mostly missense type in 80% of cases.

Conclusion: Our study confirms a leading role of PTEN gene in endometrial cancer. Our results differ from Cosmic Database only in the aspect of frame shift deletion mutations, where we observed frequency that was two times higher. Interestingly we noted mutational homogeneity concerning other important genes.

PS-09-025

Somatic neoplasms ranging from benign to malignant arising in the setting of ovarian mature teratomas: a series of cases examined in our laboratory during the course of the last year

M. Papazian*, S. Stasinopoulou, D. Bouklas, A. Ieronymaki, N. Novkovic, D. Tiniakos

*Aretaieion University Hospital of Athens, Pathology Department, Greece

Background & objectives: This study is a review of all pure mature ovarian teratomas that were examined in our institution from March-2020 to March-2021, in order to depict somatic neoplasms arising in this setting. In 4/36 cases we identified neoplasms with benign, borderline or malignant features.

Methods: All tumours had macroscopic features of mature cystic teratomas, filled with hair & sebum.

Case-1: a 45-year-old pregnant woman with an 8cm-ovarian-tumour excised during delivery/caesarean section. On dissection, a 1.8cm solid soft nodule was identified embedded in mature fatty tissue.

Case-2: a 33-year-old woman with a 4cm-unilocular-ovarian-tumour with a 1.2cm Rokitansky-tubercle.

Case-3: a 59-year-old woman with a 12cm-multilocular-ovarian-tumour.

Case-4: a 71-year-old woman with a 10.5cm-unilocular-ovarian-tumour with a 2cm Rokitansky-tubercle.

Results: Case-1: Microscopically, the 1.8cm nodule was situated in the reticular dermis & adipose tissue, underneath the dermal epithelial lining of the cyst. It consisted of hyperplastic apocrine glands with eosinophilic/foamy cytoplasm, apical snouts & luminal secretions, surrounded by a layer of myoepithelial cells. Immunohistochemically, the epithelial cells stained positive for CkAE1/AE3&GCDFP-15. p63&S-100 highlighted the myoepithelial cell-layer. Chromogranin, synaptophysin, TTF-1, PAX-8, CDX-2 & Thyreoglobulin were negative. The glands were reminiscent of lactational-breast-tissue but since ER&PR-receptors were negative, a final diagnosis of tubular apocrine adenoma was reached.

Case-2: Microscopically, inside the Rokitansky-tubercle, we identified a 0.6cm carcinoid tumour (chromogranin & synaptophysin positive) with insular-growth-pattern. The Ki-67 proliferation-index was 4% and mitotic activity was low (1 mitoses/10 HPF).

Case-3: Microscopically, the dermal epithelial lining of the cyst transitioned smoothly to dysplastic mucinous epithelium & a gastrointestinal-type-mucinous tumour with borderline features.

Case-4: Inside the Rokitansky-tubercle, a 1.6cm squamous-cell-carcinoma was identified.

Conclusion: Skin adnexal neoplasms in ovarian teratomas are rare. To the best of our knowledge, this is the first case of a tubular apocrine adenoma reported in the literature.

Our findings in Case-3 are in keeping with the well-established theory that a subset of ovarian mucinous tumours arise in the setting of teratomas.

The percentage of somatic neoplasms arising in otherwise mature teratomas was 11% in our series, surprisingly higher than originally expected and therefore we underline the importance of adequate sampling.

PS-09-026

“The Blinded Guardian”: clinical relevance of p53-null phenotype in high-grade serous ovarian cancers

V. Parrella*, C.M. Biatta, M. Paudice, G. Damiano, G. De Luca, A. Speciale, G. Cerruti, S. Mammoliti, P. Menichini, V.G. Vellone

*Department of Integrated Surgical and Diagnostic Sciences (DISC), University of Genoa, Italy

Background & objectives: TP53 is known as the “guardian of the genome” and it is crucial for high grade serous ovarian carcinoma (HGSOC) cancerogenesis, usually manifesting with p53-null or p53-overexpressed immunophenotypes. Clinical significance of the two presentations is investigated.

Methods: TP53 status was investigated on FFPE specimens with IHC (Clone DO7, Roche Benchmark®) and Sanger Sequencing (exons 2-11) in 34 HGSOCs: 16 consecutive cases of p53-null were compared with 18 cases of p53-overexpressed. The impact on overall survival (OS) between the two groups was evaluated with Kaplan-Meier curves.

Results: Cases with p53-null phenotype showed: 9 nonsense mutations, 4 in-frame deletions, 2 splice variants, and 1 in frame variants while p53-overexperessed showed 16 missense mutations and in 2 cases no mutation was detected; p53-null patients resulted slightly older, no significant differences was observed for Stage at presentation and follow-up duration, 7 p53-null and 3 p53-overexpressed patients died of the disease. P53-null patients demonstrated a significantly worse OS in the first 24 months of follow-up (HRp53-null=6.09; 95%CI: 1.52–24.51).

Conclusion: Aberrant p53 IHC expression was confirmed as a reliable characteristic of HGSOC. P53-null phenotypes harboured a peculiar set of mutations leading to an unfavourable prognosis if compared with patients with p53-overexpression. The functional reason of why p53-null HGSOC showed an unfavourable prognosis with respect to p53-overexpressed ones, need further investigation however TP53 status could be systematically investigated even in light of new target therapies in future.

PS-09-027

Multivariate analysis of histomorphological and immunohistochemical prognostic factor in endometrial carcinoma

M. Paudice*, L. Carlin, V. Parrella, M.G. Centurioni, S. Mammoliti, C. Caroti, F. Giannelli, F. Barra, S. Ferrero, V.G. Vellone

*Department of Integrated Surgical and Diagnostic Sciences (DISC), University of Genoa, Italy

Background & objectives: To investigate the prognostic value of some of the most widely studied histomorphological and immunohistochemical factors, easily accessible in every routinely pathology lab set, in endometrial carcinoma.

Methods: We enlisted patients who underwent radical hysterectomy for endometrial carcinoma. The following histomorphological and immunohistochemical factors were analysed: histotype, stage, type of infiltration, desmoplasia, intratumoral necrosis, tumour infiltrating lymphocytes, lymphovascular space invasion, oestrogen receptor α, progesterone receptor, Ki67, p53, β-catenin, e-cadherin, bcl-2 and cyclin D1. Primary endpoints were disease free survival and overall survival.

Results: Out of 206 cases eligible for our purpose, we found 151 low-grade endometrioid, 20 high-grade endometrioid and 35 non-endometrioid carcinomas. At univariate analysis, all prognostic factors excluding tumour infiltrating lymphocytes, e-cadherin, bcl-2 and cyclin-D1 were significantly associated with disease-related relapse and death. Multivariate analyses were conducted separately for the histomorphological and immunohistochemical factors and showed a significant correlation between disease recurrence and non-endometrioid histotype and low β-catenin expression. Moreover, a significant association was observed between disease-related death and non-endometrioid histotype and low β-catenin expression.

Conclusion: Our study confirms the key prognostic role of histotype in endometrial carcinoma. While the other histomorphological factors did not achieve statistical significance, at least tumour grade, stage and lymphovascular space invasion should be included in the pathologist’s report as recommended by the Royal College of Pathologists. Furthermore, in order to improve patient risk stratification, we propose to include β-catenin evaluation in the report.

PS-09-028

Adenomatoid tumours – a ten-year retrospective clinicopathological study on a rare neoplasm

A.D. Plopeanu*, A. Dema, R. Barna, A. Pascu, B.R. Nataras, S. Taban

*Department of Pathology, Emergency Clinical County Hospital Timisoara, Romania

Background & objectives: Adenomatoid tumours are rare benign mesothelial neoplasms that usually arise both in the female and male genital tract. The purpose of this study was to give insight into an infrequent neoplasm.

Methods: This study includes 16 cases of adenomatoid tumours from both female and male genital tract which were diagnosed in our centre between 2011 and 2020. Most cases were identified morphologically, but some specific cases required to be further confirmed immunohistochemically either by calretinin, D2-40, WT1, CK7 and vimentin or a combination between these markers.

Results: Of 16 tumours, 9 occurred in the female genital tract and the rest in males. 5 tumours from the male genital tract presented as mass lesions, one being diagnosed in an ectopic testicle, whereas 7 tumours from female genital tract were diagnosed incidentally. The most common location for female patients was the uterus body and for male patients the epididymis. One case was a synchronous tumour with uterine leiomyosarcoma and a mature ovarian teratoma. Histologically, half cases had tubular pattern, while the rest were trabecular or cystic. 6 tumours showed mild to moderate atypia and Ki-67 expression was evaluated in these cases, but all tumours had values below 1%.

Conclusion: Adenomatoid tumours are uncommon benign tumours that can be symptomatic most commonly in male patients because of their localization. Even though they usually present as small incidental masses, a thorough gross and microscopic examination could reveal even more cases. This neoplasm is often easily diagnosed, but in cases with unusual morphological features and nuclear atypia, immunohistochemical markers like calretinin, CK7, D2-40 and WT1 should be used in order to exclude other differential diagnoses.

PS-09-029

Importance of DNA ploidy in endometrial carcinoma

D. Riga*, K. Kosmas, E. Psychogiou, A. Papadopoulou, M. Sofopoulos, V. Michelis

*Pathology Department, General Hospital of Thoracic Diseases “Sotiria”, Athens, Greece

Background & objectives: The estimated incidence and mortality in Europe of corpus uteri cancer in the year 2020 was 6.9% and 31.3% respectively. The aim of our survey was the evaluation of DNA ploidy as predictive and prognostic factor in patients with EC.

Methods: Endometrial samples freshly resected from 168 women who underwent total abdominal hysterectomy were studied. The cytological diagnosis was confirmed by pathologists. Cytological imprint smears were obtained by touching the cut surface of fresh cancer tissues and stained with Feulgen stain.

Results: According to our results, in terms of quantitative estimation of cellular DNA, all case-control samples from proliferative, secretory and atrophic endometrium (total number 15) were exclusively diploid (DNAindex 0.9-1.1), while at least 82% of Grade 3 (total 39/168) tumours present an euploidy of DNA (DNA index <0.9 or >1.1) as opposed to about of 44% of Grade 1 (total 52/168) and Grade 2 (total 77/168) endometrial carcinomas. Furthermore, regarding the DNA intex, the ploidy balance, the degree of hyperploidy and its proliferation index, observed a statistically significant difference between all malignant lesions as well as between benign and malignant lesions (P<0.05).

Conclusion: We believe that the use of the quantitative assessment of cellular DNA may help identify tumours with high malignant potential and possible aggressive behaviour or ability relapse offering valuable information, both in prognosis and in the treatment of patients with EC. According to international literature, aneuploidy is an independent prognostic marker of relapses, a sign of malignant transformation and can therefore predict a poor prognosis.

PS-09-030

Placental infection with SARS-CoV-2 in an asymptomatic pregnant woman

M. Rodrigues*, C. Ivanova

*Hospital Distrital de Santarém, Portugal

Background & objectives: The COVID-19 pandemic raised attention to the possible complications of the disease during pregnancy. Meanwhile, no consensus has yet emerged as to the placental morphological features of this viral infection. We propose to describe a case of SARS-CoV-2 positive pregnancy.

Methods: A 28yo primigravida with asymptomatic COVID-19, presented with reduced foetal movements at 35W,5D of gestation. A pathological cardiotocography prompted a C-section. The female live birth had low weight for gestational age, respiratory distress and bradycardia, Apgar 2/7/9, and was negative for SARS-CoV-2. A week after neonatal unit admission, she fully recovered. The placenta was sent to pathologic examination.

Results: It was received a monochorionic and monoamniotic, discoid placenta, with 18x17x2cm and 338g (weight below the 25th percentile for gestational age), mild opaque, yellowish foetal membranes, a normocoiled umbilical cord with 31x1.2cm, paracentral insertion and three vessels. Examination of the cut surface showed a central area of infarction, with 4cm in the greatest dimension. Microscopically, the placental parenchyma showed accelerated villous maturation, diffuse and severe chronic histiocytic intervillitis, areas of organized infarction, fibrin deposition and chorangiosis. Immunohistochemistry for SARS-CoV-2 antibody was performed, showing diffuse villous trophoblastic staining.

Conclusion: The study of the placental pathology could allow us to understand the complications or eventual defensive mechanisms of the SARS-CoV-2 infection. Chronic intervillitis is an inflammatory response for this viral infection, as referred in other related studies, and is associated with worse foetal outcome. Furthermore, the strong immunostaining in the villous trophoblast cells, a rare feature in asymptomatic COVID-19 cases, raises questions about the possible protective function of this cells in containing the infection.

PS-09-031

Heavy metals exposure decrease the progesterone expression in the rat myometrium

K. Sikora, M. Lyndin, R. Moskalenko, Y. Kuzenko, A. Romaniuk*

*Sumy State University, Ukraine

Background & objectives: The progesterone receptors (PR) activity in the uterus helps to regulate critically important reproductive functions in mammals. However, impaired progesterone production and sensitivity caused by the exogenous pollutants may lead to unpredictable sexual health disorders.

Methods: Uterine tissue samples were obtained from adult female rats in the estrus phase. Before uteruses removal, rodents were randomly divided into two groups: rats of Group I received HM salts mix (Zn/Cu/Fe/Mn//Pb/Cr) for 30 days, whereas rats of Group II served as control. The immunohistochemical investigation was performed utilizing primary antibodies to PR (rabbit anti-PR Monoclonal Antibody – SP2 clone).

Results: The strong positive nuclear PR immunolocalization was found in almost all myocytes of rat uterine circular and longitudinal muscle layers of Group II. Compared to the control PR expression, an immunohistochemical investigation of rats myometrium of Group I allowed to detect the decrease of PR-positive muscle cell number (p<0.01). Besides, the nuclear PR signal intensity in the myometrium was simultaneously reduced.

Conclusion: Rat myometrium undergoes changes of progesterone receptors level physiological activity due to the prolonged influence of heavy metals. The pollutants-induced changes contribute to the significant decrease of progesterone receptors positive cells and their expression intensity by uterine myocytes, although not reaching the critically low level.

PS-09-032

Mismatch repair protein expression in endometrial cancer: are clinicians using it?

F. Rosa*, M. Veríssimo Dias, I. Claro, A. Félix

*Instituto Português de Oncologia de Lisboa Francisco Gentil, Portugal

Background & objectives: Mismatch repair protein expression (MMR) universal testing is recommended for endometrial cancer allowing Lynch syndrome (LS) identification, assists diagnosis, prognosis and guides treatment but is still mostly unused[1]. We reviewed our recent testing experience in MMR-immunoexpression (MMR-IHC).

[1] (ESMO guidelines)

Methods: Between 2018 to 2020, we found 478 endometrial carcinoma (EC) cases and checked the report for MMR-IHC for the 4 MLH1, PMS2, MSH2, MSH6 proteins and for further molecular studies (methylation and Next Generation Sequencing/MLPA) of cases with abnormal IHC testing.

Results: Mean age was 69yrs. (range: 31-92); distributed as endometrioid(71.8%); serous(9.8%); clear cell(4%); carcinosarcoma(6.7%); undifferentiated(4.2%); mixed(3.1%); others(0.4%). Although universal study is recommended in our hospital since September 2019, only 146 cases(30.5%) had MMR-IHC performed distributed by year as follows: 20/165(2018); 54/181(2019) and 72/132(2020). 50 cases had abnormal MMR-IHC(34.2%). The loss of MLH1 occur in 74%; PMS2 in 78%; MSH2 in 22% and MSH6 in 14%. Loss by histological-type: endometrioid(74%), clear cell(2%), mixed(8%), undifferentiated carcinomas(14%), others(2%). Carcinosarcomas(0/32) and serous carcinomas(0/47) had normal MMR-IHC. Molecular testing identified 2 cases of Lynch Syndrome, 2 with MLH1 methylation, 5 without MMR gene mutations and 20 still in evaluation.

Conclusion: The rate of the immunohistochemistry testing in EC was around 35 % in our hospital, in the last 3 years. The immunohistochemical results of MMR evaluation are similar to what is described in the literature. The rate of confirmation of MMR-IHC is very low (patients refusal, death) and lengthy. The large absence of MMR-IHC in the pathological reports may indicate that clinicians are not using the MMR data.

PS-09-033

High-grade ovarian carcinoma molecular subtypes: manual and neural networks ensemble-based reproducibility

A. Tregubova*, A. Asaturova, V. Kometova, M. Shamarakova, A. Magnaeva, A. Zanozin, N. Redkina, A. Palicelli, V. Naumov, P. Borovikov

*FSBI "National Medical Research Center for Obstetrics, Gynaecology and Perinatology after V.I. Kulakov" Ministry of Healthcare Russian Federation, Russia

Background & objectives: Primary ovarian high-grade serous carcinoma (HGSC) has been classified into 4 molecular subtypes: Mesenchymal, Immunoreactive, Proliferative and Differentiated. In 2016 R. Murakami et al. proposed the algorithm based on morphological and immunohistochemical findings to determine them in histological slides.

Methods: In our study we tested the morphology-based classification system presented by R. Murakami et al. and compared the results of manual and neural network-based analysis. The latter identifies the molecular subtype using both whole slide images and patient sequencing data from the TCGA database. The agreement between pathologists pairs were analysed with Cohen's kappa.

Results: The study revealed that convolutional neural network showed high level of reliability (resulting multi-class accuracy on separate test set after 40 epochs equals 0.816), whereas the accuracy of morphological diagnoses was low to moderate (Cohen’s kappa for all pathologists was 0,305 – 0,605). Mesenchymal subtype was diagnosed by pathologists correctly in 56,1% cases, immunoreactive - in 17,9 %, proliferative - in 21,1% and differentiated subtype - in 25,7%.

Conclusion: Obtained dataset indicates that using only morphological criteria to distinguish molecular subtypes of HGSC does not seem to perform in routine practice. It may be feasible to use artificial intelligence as a powerful diagnostic tool for molecular subtyping of HGSC, but the neural network needs a larger sampling for high precision results.

PS-10 | Haematopathology Posters

PS-10-001

Solitary plasmocytoma of chest wall: clinicopathological study of 15 cases

R. Ayadi*, E. Braham, M. Mlika, F. Sassi, S. Ben Cheikh, A. Ayadi, O. Ismail, F. El Mezni

*Hôpital Abderrahmane Mami de Pneumo, Tunisia

Background & objectives: Solitary plasmocytoma of the bone is a rare disease that account for only about 5% of malignant plasma cell tumours. Infrequently, it is seen in ribs and sternum. The aim is to present clinicopathological features of this disease.

Methods: We report a retrospective study of 15 cases of solitary plasmocytoma diagnosed at our department of pathology between 2004 and 2020. Radiological findings and bone narrow examination does not show any other localisation. The immunohistochemical study includes CD20, CD79, CD138, Kappa and Lambda light chain antibodies.

Results: There were 12 male and 3 female patients, aged between 50 and 81 years with a mean of 67. Ten plasmocytoma were localized in ribs, four in the sternum and one in the scapula. The diagnosis was made on transparietal biopsy in 13 cases and on surgical resection in 2 cases. Microscopic examination showed diffuse sheet of monotonous population of dark blue round cells, few with eccentrically placed nucleus and eosinophilic cytoplasm. Bi–nucleated forms were seen. On immunohistochemistry, tumour cells express CD138 in 15 cases, CD79a in 15 cases, Kappa light chain in 6 cases and lambda light chain in 9 cases. They were negative for CD20 and CD3.

Conclusion: Solitary plasmocytoma of chest wall is a rare entity with low specific clinical and radiological expression. The diagnosis is based on histology with identification of localized tumour composed of monoclonal plasma cells.

PS-10-002

Low indoleamine 2,3-dioxygenase 1 (IDO1) and high CD204 expression in the tumour microenvironment are independent adverse prognostic factors in mantle cell lymphoma patients

S. Chuang*, W. Chuang

*Chi-Mei Medical Center, Taiwan

Background & objectives: Indoleamine 2,3-dioxygenase (IDO)1(+) dendritic cells and CD204(+) macrophages contribute to immune regulation in tumour microenvironment, but their clinical significance in mantle cell lymphoma (MCL) is largely unknown. We studied the prognostic value of IDO1(+) cells and CD204(+) cells in MCL.

Methods: A total of 127 cases of MCL from Taiwan were included. The mantle cell lymphoma international prognostic index (MIPI) was calculated, and a MIPI of 5.7 or higher was considered high. Immunohistochemical study for Ki-67, MYC, p53, IDO1 and CD204 was performed, and the cut-off for high expression was at least 30%, 20%, 30%, 5% and 5%, respectively.

Results: Ki-67, MYC and p53 were expressed by tumour cells, whereas IDO1 and CD204 were mainly expressed by dendritic cells and macrophages, respectively. Using univariate analysis, high MIPI score, high Ki-67 expression, high MYC expression, high p53 expression, low IDO1(+) dendritic cells and high CD204(+) macrophages were significant adverse prognostic factors (P = 0.00059, 0.026, 0.00080, 0.026, 0.010 and 0.0032, respectively). Using multivariate analysis, only high MIPI score (hazard ratio (HR) 2.98; 95% confidence interval (CI) 1.66-5.35; P = 0.00026), low IDO1(+) dendritic cells (HR 2.95; 95% CI 1.57-5.54; P = 0.00076) and high CD204(+) macrophages (HR 2.35; 95% CI 1.29-4.27; P = 0.0050) were independent adverse prognostic factors.

Conclusion: Here we report for the first time that low IDO1(+) dendritic cells and high CD204(+) macrophages in the tumour microenvironment are independent adverse prognostic factors for MCL patients. Modification of the tumour microenvironment might be of therapeutic valve for MCL patients. Future functional studies would be helpful to clarify the roles of these cells in MCL.

PS-10-003

Neoplasm of large B lymphoid cells - a rare central nervous system lymphoma: analysis of 2 cases

M. Cristian*, M. Aschie, G.I. Baltatescu, A.A. Nicolau, M. Enciu, G.C. Cozaru, L. Mocanu, A. Toma, M. Deacu

*CEDMOG, Ovidius University, Romania

Background & objectives: Central nervous system (CNS) involvement by lymphoma is distinctly rare and clinically aggressive. The aim of this study is to present the clinicopathological features of histopathologically-proven cases of CNS lymphoma to further characterise this rare entity.

Methods: We performed a retrospective study on Non-Hodgkin Lymphoma cases from 2015 to 2021 in South-Eastern Romania. To date, 105 cases suitable for our study have been reported and we describe the only 2 cases of CNS Lymphoma. Further to the histopathological examination, an immunohistochemical evaluation was mandatory by using monoclonal antibodies (CD3, CD10, CD15, CD20, CD45, CD79a, Bcl-2, Bcl-6, Ki67).

Results: Two patients, a 57-year-old female and a 65-year-old male, who presented clinical and imagistic features of a CNS malignancy, both localized in the frontal and fronto-parietal lobe. Clinical and imagistic correlations raised the possibility of glioblastoma but histopathological examination established the diagnosis of CNS lymphoma. Histopathologically, both cases were characterized by a diffuse proliferation of medium/high-sized lymphocytes, with a high mitotic rate. Immunohistochemistry study showed positivity for CD20, CD45, Bcl-2, CD79a with a high nuclear proliferation marker (Ki67 80-90%), while the other biomarkers (CD3, CD10, CD15, CD30, EMA) were negative. These findings established the certainty diagnostic of diffuse large B-cell central nervous system lymphoma.

Conclusion: Clinical and imaging features of primary CNS lymphoma and glioblastoma are highly variable and sometimes similar, difficult to differentiate, and this is why it is important to recognize this entity in order to avoid misdiagnosis. The morphological evaluation of the presented cases has confirmed the diagnosis and has ensured adequate treatment and follow-up. The histopathological and immunohistochemical evaluation played an essential role in establishing the final diagnosis, in order to determinate the neoplastic proliferation line and the subtype of lymphoma.

PS-10-004

Matrix metalloproteinases and their inhibitors in JAK2-mutated myeloproliferative neoplasms

D. Gogoleva*, G. Sychugov

*South Ural State Medical University, Russia

Background & objectives: The aim of study was to assess the specificity of expression of matrix metalloproteinases 2 and 9 (MMP2, MMP9) and their inhibitors (TIMP1, TIMP2) in JAK2-mutated myeloproliferative neoplasms (MPN) and their possible correlation with the grade of bone marrow fibrosis.

Methods: We investigated 55 bone marrow biopsies of patients with JAK2-mutated MPN. Whole-slide sections were immunostained using antibodies against MMP-2, MMP-9, TIMP-1, TIMP-2 and scored by ImageJ plugin software. The same biopsies were silver-stained and assessed using the semiquantitative bone marrow fibrosis (MF) grading system proposed by Thiele Jet al.

Spearman’s rank-order correlation was calculated. Statistical significance was set at p<0.05.

Results: MMP2 and TIMP2 expression was observed mostly in megakaryocytes. MMP9 expression was observed in neutrophils, macrophages, and stromal fibroblastic components. TIMP1 expression was observed exclusively in stromal fibroblastic components.

Grade of fibrosis was assessed as MF0 in 19/55 (34,5%), MF1 in 15/55 (27,3%), MF2 in 14/55 (25,5%), MF3 in 7/55 (12,7%). The overall number of cases with fibrosis of any grade was 36/55 (65,5%).

There was weak negative correlation between TIMP2 and the grade of fibrosis (rho= -0.293, p=0.030, n=55), weak negative correlation between MMP2 and fibrosis of any grade (rho= -0.299, p=0.027, n=55) and moderate negative correlation between TIMP2 and fibrosis of any grade (rho= -0.367, p=0.006, n=55).

Conclusion: In a bone marrow MMP and TIMP expression was observed in megakaryocytes in addition to the typical expression in inflammatory cells and stroma.

The existence of correlation between MMP regulation and bone marrow fibrosis is likely to improve understanding of JAK2-mutated MPN pathogenesis. It may be useful for supporting the diagnosis, evaluation of prognosis and the development of possible matrix-targeted treatment.

PS-10-005

Precision medicine development and validation of a multi-fluorescent automated assay to quantify BCL2 and CCND1 expression in CD138 positive bone marrow multiple myeloma (MM) cells

T. Khong*, I. Savvidou, C. Hader, A. Spencer

*Myeloma Research Group, Australian Centre for Blood Diseases, The Alfred Hospital/Monash University, Australia

Background & objectives: MM remains incurable despite adoption of novel therapeutics. We describe the development and validation of an automated platform from bone marrow trephines to identify t(11;14) patients with overexpression of CCND1 or BCL2 who may benefit from venetoclax, a BCL2 inhibitor.

Methods: Antigen retrieval (Dako PT Link) were performed on bone marrow trephines followed by primary antibodies staining (anti-CD138, anti-BCL2 and anti-CCND1) then specific fluorophores (CD138–AF647, BCL2–AF594 and CCND1–AF488) on an Auto-Stainer Link 48 and scanned using Olympus VS120 slide scanner. Scanned images were assessed by 2 haematologists using the OlyVIA software (Olympus) and with an automated assay (in-house ImageJ script).

Results: 41 trephines comprised of 4 cohorts; t(11;14), t(4;14), chr14-translocation-other-than t(4;14), and MM with normal karyotype/FISH (normals) were analysed. Comparisons between two haematologists and the automated script had Spearman correlation of r=0.974 (CD138), r=0.778 (BCL2) and r=0.6744 (CCND1). With the automated assay, CCND1 was over-expressed in the CD138+ cells in the t(11;14) cohort compared to normals (p=0.02). 50% of the chr14-other cohort over-expressed CCND1 in CD138+ cells, possibly from patients harbouring t(11;14). No CD138+/CCND1+ cells were observed in the t(4;14) cohort. Utilising automated quantification and defining low BCL2 expression as < 28.17% (median-1STDEV); intermediate/high BCL2 expression on CD138+ cells was identified in 73% of cases and not restricted to t(11;14) subgroup.

Conclusion: We identified MM patients with CD138+ cells expressing high CCND1 and/or high BCL2 expression utilising automated triple immunofluorescent staining of bone marrow trephines. CCND1 and BCL2 expressions, in accordance with the literature, surpasses the t(11;14) subgroups defined traditionally by FISH, identifying a larger cohort of patients that could potentially benefit from the addition of venetoclax in their therapeutic algorithm.

PS-10-006

Next Generation Sequencing (NGS) in acute myeloid leukaemia: a centre experience

F. Öz Puyan*, S. Karaman Gülsaran, E.G. Ümit, İ. Usta, E. Taştekin, N. Can, O. Kirkizlar, B. Binboga Kurt, U. Demirci, A.M. Demir

*Department of Pathology, Trakya University Faculty of Medicine, Turkey

Background & objectives: Acute myeloid leukaemia (AML) is an aggressive malignancy of hematopoietic precursor cells. Incidence increases with age. Although the aetiology is unclear, evolution from a clonal haematopoiesis or any other stem cell disorder is most likely in older patients.

Methods: Mutational profile, clinical data and histopathological findings of 30 patients, diagnosed with AML based on the 2017 update of World Health Organization (WHO) classification of myeloid neoplasms were evaluated. Bone marrow biopsy was done for histopathological examination. CD34 and CD117 immunoexpression were evaluated on the blasts. Bone marrow aspiration was used for flow-cytometric analysis and molecular studies.

Results: Mean age was 64,40 years. 13 were female (43,3%),17 were male (56,7%). Based on initial clinical evaluation, 18 patients were considered as de-novo AML (60%), 12 patients as transformed/relapsed AML. Mean survival was 9,13 months. 12 patients died (40%). QIAact Myeloid DNA NGS Panel revealed following results: Mutations of TP53 and RAS gene in 7 (23,3%), ASXL1 in 9 (30%), TET2 in 9 (30%), DNMT3A in 9 (30%), IDH mutations in 7 (23,3%), FLT3 in 6 (20%), SF3B1 in 7 (23,3%) patients. Among de-novo AML patients (5 cases) with TP53 or RAS mutation, mean survival was 2,2 months, while in patients without these mutations, mean survival was 21,57 months (p=0,045).

Conclusion: As a novel and sophisticated method, NGS supports the clinical assessment of AML patients and contribute to the concept of individualized prognostic expectation as well as treatment. Particularly in patients who are otherwise considered as de-novo AML, determination of clonal haematopoiesis may effect on both treatment, stem cell transplantation as well as follow up decisions.

PS-10-007

Langerhans cell histiocytosis: an institutional experience

M. Solórzano*, X. Vilaseca Creus, A. Falgueras i Sánchez, M.R. Rodriguez Millán, O. Moreno Gómez, M. Gómez Núñez, M. Vidal Borrego, C. Blázquez Mañá

*Pathology Department, Parc Taulí Hospital Universitari, Sabadell, Spain; Universitat Autònoma de Barcelona, Spain; Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain

Background & objectives: Langerhans Cell Histiocytosis’ pathogenesis (LCH) is still debated nowadays between a reactive or neoplastic aetiology, the latter supported mainly by BRAF p.V600E mutation.

We describe the association between cases diagnosed with LCH in our entity and their association with BRAF.

Methods: Retrospective observational study of cases diagnosed with LCH in our institution from 2010 to 2020. Epidemiological data, clinical course and evolution are collected. Histological preparations are reviewed, including BRAF antibody (VE1, Roche) by immunohistochemistry (IHQ). Quantitative PCR (qPCR, IdyllaTM) for BRAF is performed in 8 of the 11 cases at the time of writing.

Results: Eleven diagnosed cases of LCH have been collected, 9 in adults (8 female, mean age: 56 years). Five cases (66%) were associated with some neoplasm, most of them being solid (75%). In 2 of these 5 cases, the neoplasm was diagnosed concomitantly with LCH. In another 2 cases the neoplasm preceded the LCH and in the other one the diagnosis of LCH was concomitant with the recurrence of the neoplasm.

Of the 11 cases, 6 (54%) were positive for BRAF by IHQ. Of the 8 cases evaluated by qPCR, 3 (37.5%) showed BRAF mutation (all 3 with immunohistochemical staining), of which 2 were associated with second neoplasms and poorer prognosis.

Conclusion: Langerhans Cell Histiocytosis is a rare entity of controversial aetiology. It is more frequent in women, and its presentation should raise the suspicion of a second neoplasm. Its association with BRAF mutation has been observed by IHQ and by qPCR, which would support its clonal origin. BRAF-mutated LCH could be more frequently associated with second malignancies and, thus, worse prognosis.

PS-10-008

Association of STAT3 expression and enhanced angiogenesis in primary extranodal diffuse large B cell lymphoma

S. Stojnev*, M. Krstic, A. Ristic, I. Petkovic, I. Conic, A. Ristic Petrovic, J. Todorovic, M. Mladenovic

*Department of Pathology, Faculty of Medicine, University of Nis, Serbia

Background & objectives: Signal transducer and activator of transcription 3 (STAT3) is critically involved in fundamental cellular processes, including cell survival, proliferation, and angiogenesis. We investigated the correlation between STAT3 and intratumoral microvascular density in primary extranodal diffuse large B cell lymphoma (DLBCL).

Methods: Immunohistochemical analysis of STAT3 expression was performed on tissue samples of 59 patients with primary extranodal DLBCL, treated with R-CHOP. Microvessel density (MVD) was assessed as a number of blood vessels per 1 mm2 of tumour tissue, via identification of endothelial cells by immunostaining to CD31. Based on the average value, tumours were divided into low- and high-MVD groups.

Results: Strong expression of STAT3 was found in 37.3% of cases, while high MVD was observed in 52.5% of the tumours. STAT3 overexpression was significantly associated with high MVD in the tumour microenvironment (p=0.001). Moreover, STAT3 was strongly linked to non-GCB immunophenotype of DLBCL, determined by Hans’ immunohistochemical algorithm (p=0.002) and poor overall survival of the patients (p<0.001).

Conclusion: Our study indicates that strong STAT3 immunoexpression in primary extranodal DLBCL is firmly associated with increased intratumoral angiogenesis determined by MVD. This suggests that STAT3 positive cases of this aggressive disease may benefit from antiangiogenic therapeutic strategies.

PS-10-009

Anaplastic large cell lymphoma (ALCL) – the expression profile of CD30-IRF4-MYC axis

A. Szumera-Cieckiewicz*, E. Paszkiewicz-Kozik, B. Bikowska-Opalach, B. Ziarkiewicz-Wróblewska, B. Gierej, B. Pytlak, D. Owczarek, M. Kawecka, K. Sokół, M. Łukasik, M. Prochorec-Sobieszek, G. Rymkiewicz

*Institute of Haematology and Transfusion Medicine, Diagnostic Haematology Department, Maria Sklodowska-Curie National Research Institute of Oncology, Department of Pathology and Laboratory Medicine, Poland

Background & objectives: Anaplastic large cell lymphoma (ALCL) is a T cell neoplasm with uniform CD30 expression, loss of T cell antigens, and the presence[ALCL-ALK(+)]/lack[ALCL-ALK(-)] of ALK fusion gene. Recently, MYC expression was identified as an adverse prognostic factor that IRF4/MUM1 could modulate.

Methods: We included in the study 39 cases of ALCL: 25 (64%) ALCL-ALK(-).and 14 (36%) ALCL-ALK(+). All cases were revised according to the WHO diagnostic criteria. The immunohistochemical assessment included expression profile of CD30 (Ber-H2,RTU,Agilent/Dako), IRF4/MUM1 (MUM1p,RTU,Agilent/Dako), and MYC (Y69,1:100,pH 9.0,Abcam) on ALCL cells. The CD30 and IRF4/MUM1 were evaluated as positive/weak/negative cases and MYC as low/high "expressors".

Results: The CD30-IRF/MUM1-MYC expression profile in the ALCL-ALK(-) vs. ALCL-ALK(+) groups showed minor differences. All cases were CD30 positive, but ALCL-ALK(+) demonstrated a higher percentage of weak expression (14.3% vs. 8.7%). Strong IRF4/MUM1 was exhibited in 87% of ALCL-ALK(-) and 76.9% of ALCL-ALK(+) cases. Low vs. high expression of MYC was seen in ALCL-ALK(-) and ALCL-ALK(+), respectively: 47.8% vs. 52.2% and 61.5% vs. 38.5%. High MYC "expressors" were accompanied by stronger CD30 (94.1% vs. 81.3%) and IRF4/MUM1 (94.1% vs. 73.7%) reactions.

Conclusion: ALCLs, both ALK(-) and ALK(+) show a high level of IRF4/MUM1 and MYC expression profile. It is essential since IRF4/MUM1 targets immunomodulatory drugs such as lenalidomide which has a clinical impact on patients with peripheral T-cell lymphomas. Also, single studies reported the importance of MYC in stratifying or predicting the prognosis. We believe that further analysis, including clinical data, will be the crucial point of evaluating IRF4/MUM1 and MYC expression as prognostic biomarkers.

PS-10-010

Bone marrow immune microenviroment in patients with myelodysplastic syndromes

Z. Tsakiraki*, S. Papageorgiou, A. Spathis, A.R. Gouloumis, A. Pouliakis, A. Bouchla, T. Thomopoulos, E. Angelopoulou, I. Panayiotides, V. Pappa, P. Foukas

*2nd Department of Pathology, National and Kapodistrian University of Athens, School of Medicine, “Attikon” University Hospital, Greece

Background & objectives: Myelodysplastic syndromes (MDS) constitute a group of clonal expansions of hematopoietic stem cells. Our objective is to investigate the immune landscape in bone marrow biopsies from patients with intermediate/high risk MDS, and its role in the outcome of 5-Azacytidine treatment.

Methods: The study population consists of 82 patients treated with 5-AZA. BM specimens before (n=82) and during treatment (n=31) were immunostained for CD3, CD8, CD20 and CD138 for T, cytotoxic T, B and plasma cells respectively. Positive cells were counted in 5 areas with the highest density of CD8 cells and all cell counts were normalised to 100.000μm2 of tissue area.

Results: In biopsies before treatment, the presence of lymphoid aggregates significantly correlated with high densities of CD8+ T and B cells (p=0.013 and p=0.035 respectively). In addition, higher CD3+ T cell densities also significantly correlated with increased overall survival (OS) (p=0.016), overall response (p=0.035) and complete remission (CR) (p=0.035). Moreover, higher plasma cell density was found in patients that eventually transformed to AML (p=0.022). In biopsies after treatment, higher BM cellularity was negatively correlated to OS (p=0.009), whereas responders showed decreased cellularity (p<0.001). Moreover, responders in general, as well as complete responders in particular showed decreased CD8+ T cell densities (p=0.010 and p=0.026, respectively) in follow-up biopsies.

Conclusion: Our preliminary results indicate that the density of cells of adaptive immunity in the bone marrow specimens may significantly contribute to both response and survival of high risk MDS patients treated with 5-AZA.

PS-10-011

Comparative immunohistochemical study of T4, T8 and FOXP3+ cells in tumour microenvironment of primary mediastinal B-cell lymphoma and mediastinal nodular sclerosis classical Hodgkin lymphoma

S. Tzorakoleftheraki*, P. Zymaris, T. Papamitsou, T. Koletsa

*Department of Pathology, School of Medicine, Aristotle University of Thessaloniki, Greece

Background & objectives: Primary mediastinal B-cell lymphoma (PMBL) and nodular sclerosis classical Hodgkin lymphoma (NSCHL) are the most common primary mediastinal B- cell lymphomas, which share similar clinical and histopathological features. We compare the T-cell populations in their microenvironment (TME) using immunohistochemistry.

Methods: Twenty-five cases were retrieved from the archives of our Department, 13 histologically diagnosed as PMBLs and 12 as mediastinal NSCHLs. Tissue microarrays (TMAs) with two cores per case were constructed and immunohistochemistry with CD4, CD8 and FOXP3 antibodies was performed. CD4+/CD8+ ratio, FOXP3+ cell percentage, eosinophil and mast cell densities were evaluated. A statistical analysis using IBM SPSS Statistics v25 followed.

Results: CD4+/CD8+ lymphocytic ratio, FOXP3+ cells, eosinophil and mast cell densities were significantly higher in NSCHL (p<0.05). FOXP3+ cells were negatively associated with eosinophil density in NSCHL (r=-0.676, p<0.05). In PMBL, CD4+ cell percentage of total TME cells was positively associated with FOXP3+ cell percentage (r=0.889, p<0.01). Interestingly, in three (3/13, 23.1%) PMBL cases, FOXP3 positivity was observed in neoplastic B-cells, as well. In these cases, staining intensity was variable, often weak to moderate, in a proportion of positive cells ranging from almost 50 to 90% of the total neoplastic population. In addition, a positive association was found between mast cell density and CD8+ cells (r=0.585, p<0.05) in PMBL.

Conclusion: Our findings exhibit a clear difference between the TME of the two entities. Globally, T4 cells are predominant in NSCHL and T8 cells in PMBL. FOXP3+ T-cells are more abundant in NSCHL than in PMBL. There seems to be an interaction between T8 cells and mast cells in PMBL, which needs further investigation. The observation of FOXP3+ neoplastic B-cells in a subset of PMBLs should be established in larger series, as well as its possible clinical and biological significance.

PS-11 | Head & Neck Pathology Posters

PS-11-001

Visual versus computer-assisted evaluation of PD-L1 expression in head and neck squamous cell carcinoma

J.A. Baena-Del Valle*, M. Palau-Lázaro, A.M. Baldión-Elorza, C. Buriticá-Cifuentes, P. Bernal-Trujillo, G. Ucrós-Rodríguez, Á. Muñóz-Pérez, A.V. Ospino-Serrano, J. Segovia-Gómez, C.A. Ariza-García, A. Escallón-Cubillos, J.A. Hakim-Tawil, P.A. Rodríguez-Urrego

*Fundación Santa Fe de Bogotá, Colombia

Background & objectives: Guidelines to assess PD-L1 expression in head and neck squamous cell carcinoma (HNSCC) have been published. However, interpretation is challenging and time consuming. The aim was to develop a computer-assisted evaluation of PD-L1 expression and compare to the visual assessment.

Methods: 37 samples from HNSCC patients from the Colombian cohort of the InterCHANGE study (IARC) were included. TMAs were constructed and Immunohistochemistry with PD-L1 (22C3-PharmDx-Agilent/Dako) was performed. The Combine Positive Score (CPS) was assessed independently by five pathologists. Their scores were compared to digital scores obtained by a machine learning-assisted methodology using QuPath (v0.2.3).

Results: PD-L1 expression (CPS ≥1) was 89% (33) and 97% (36) in the visual and digital assessment, respectively. CPS ≥20 was more frequently seen in the digital methodology (78%) than in the visual scoring (40%). Visual and digital CPS scores showed a spearman correlation coefficient of 0.7146 (p=0.0001), and there was a moderate agreement between the pathologist scores and the digital ones when grouped into ranges (<1, ≥1-19, ≥20) (weighted-kappa of 0.4127, p=0.0003).

Conclusion: We show a high prevalence of PD-L1 expression in HNSCC as previously reported. There was a substantial correlation between the visual and digital scores. However, some cases (3) reported as negative (CPS <1) by the pathologists were detected as positive by the digital methodology. We consider that digital assessment of PD-L1 expression is feasible and especially helpful when evaluating cases that are close to a cut-off score. However, this requires an excellent digital slide resolution and exclusion of artifacts.

PS-11-002

Adamantinoma-like Ewing sarcoma of the head and neck: a case series of a rare and challenging diagnosis

M. Bal*, A. Shah, N. Mittal, S. Rane, B. Rekhi, A. Patil

*Tata Memorial Centre, Homi Bhabha National University, India

Background & objectives: Adamantinoma-like Ewing sarcoma (ALES) is a rare malignancy characterized by EWSR1-ETS related fusions and epithelial differentiation. ALES is being increasingly recognised in the head and neck. We aimed to study the clinicopathologic spectrum of ALES diagnosed at our institute.

Methods: A retrospective review of the clinical and pathologic features of all ALES cases was performed after confirming the diagnosis.

Results: Seven patients were analysed. The age range was 7-44 years (4 males; 3 females). Tumours were distributed in the maxilla (n=2), parotid (n=2), nasal cavity (n=1), alveolus (n=1), and thyroid (n=1). Tumour size was 1.6-5.5 cm. Tumours had infiltrative edges, monomorphic cells, nested-lobular architecture, and interlobular fibrotic stroma. Cells were round (n=4) /basaloid (n=3). Palisading (n=3), squamous differentiation (n=2), keratinization (n=1), follicle-like cysts (n=3), calcification (n=4), necrosis (n=5) was observed. On immunohistochemistry, cytokeratins (100%), p40 (100%), CD99 (100%), and synaptophysin (57%) were positive; markers for NUT/SMARCB-1 deficient/myoepithelial/ lymphoid/myoid/melanoma were negative. EWSR1 rearrangements were identified in 5/5 patients who were tested. One patient developed recurrence; 3 developed metastases.

Conclusion: ALES is a rare and aggressive malignancy that mimics diverse neoplasms common in the head and neck region. Awareness of the morphologic and immunohistochemical spectrum of this tumour is essential to avoid diagnostic errors.

PS-11-003

Subepithelial fibrinous accumulation and associated epithelial downward proliferation in laryngeal nodules

K. Basak*, Ö. Günhan, M. Çaputçu, Ş. Sağlam, M. Atlı, D. Demir, S. Oğuztüzün

*University of Health Sciences, Kartal Dr.Lütfi Kırdar City Hospital, Department of Pathology, Istanbul, Turkey

Background & objectives: Fibrinoid accumulation in larynx and in time results with overgrowths. Mucosal epithelium may proliferate downward to organize and remove the fibrinoid accumulation. This study focused on the fibrinoid substance accumulation and the mechanisms of the associated squamous epithelial proliferation.

Methods: Five hundred and seventy-five laryngeal nodules re-examined and 111 of them with varying degrees of irregular downward squamous epithelial proliferation included to study. Immunohistochemically for CK5/6, CK17, CK14, collagen type I, collagen type III, collagen type IV, and fibrinogen was performed. The modified Masson's trichrome method was used for histochemical staining of collagen.

Results: Some of the nodules showed acute lesions having mostly subepithelial fibrin accumulation and oedema. The relatively mature lesions mostly contain dense collagen fibres. The intensity of collagen type III was inversely proportional to the amount of fibrin accumulation. Collagen type IV was found only in the epithelial and vascular basement membranes. The decrease in fibrin staining intensity and presence of collagen type I and type III indicates the replacement of fibrin with collagen. Basal-type keratins show more pronounced staining in the regenerated areas of the epithelium. As the laryngeal subepithelial fibrinoid accumulation was replaced with collagen, the regression of the lesion became difficult.

Conclusion: Irregular squamous epithelial proliferation exists independent of the stage of the lesion. Although the aetiology is different, the resulting lesions are histologically similar to those seen in the ligneous mucosal disease.

PS-11-004

Sarcoidosis in metastatic lymph nodes of solid cancer: a fortuitous discovery and complex association

N. Ben Abdeljelil*, B. Lahbacha, A. Bellalah, C. Chabaane, M. Njima, L. Njim, R. Hadhri

*Department of Pathology, Chu Fattouma Bourguiba Monastir, Tunisia

Background & objectives: Sarcoidosis is a benign multisystem granulomatous disease. It is being reported to be associated with malignancies, however, the exact frequency is not yet established.

We tried to evaluate a possible causative association with literature review.

Methods: We report four cases of fortuitous discovery of sarcoidosis in metastatic lymph nodes of thyroid and breast carcinoma collected over a period of 4 years in the department of pathology of the university hospital of Monastir.

Results: All patients were female. Patients ages ranged from 40 to 65 years with an average age of 54 years.

In 3 cases, the diagnosis of sarcoidosis was made in metastatic lymph nodes from lymph node dissection in papillary thyroid carcinoma. In the last case, the diagnosis was made in metastatic lymph nodes from axillary lymph node dissection for breast carcinoma. No patient has a history of systemic disease. Histologically, metastatic lymph nodes show a granulomatous inflammation without caseous necrosis. Slight fibrinoid necrosis in the centre of some sarcoidotic granulomas has been observed. Schumann bodies were seen in 2 cases without any astroid body.

Conclusion: Relationships between granulomatosis and cancer have been described for a long time herefore, it is important for clinicians to be aware of the simultaneous occurrence of sarcoidosis and metastatic malignancy, especially when the biopsy shows a granulomatous reaction. All cancer types can be observed. Hypothesis of a possible association and a possible increased risk of cancer include the chronic inflammation, the immune system dysregulation and of sarcoidosis. However, this association could be considered as a protective factor against cancer relapse.

PS-11-005

Ameloblastoma of the jaw: clinico-pathological study

A. Ben Mabrouk*, A. Bdioui, A. Bourigua, Z. Lajmi, E. Benammou, H. Hamchi, T. Dahmoul, S. Hmissa

*Department of Pathology Sahloul Hospital, Tunisia

Background & objectives: Ameloblastoma is rare benign tumour of the odontogenic epithelium. It accounts for only 1% of all jaw tumours and about 11% of all odontogenic tumours. Our objective is to report the characteristics of the different types of ameloblastoma and their evolutionary aspect.

Methods: In this work, we included 6 cases of ameloblastoma, collected in the pathology department at the Sahloul University Hospital in Sousse (Tunisia), over a period of two years: (January 2019-December 2020).

Results: The sex ratio was 1:5. The average age of this population is 52 years. The mandibular localization represented in 5 cases, including 3 cases at the level of the mandibular angle,1 case at the level of the ascending branch and 1 case at the level of the horizontal branch. One patient had a double mandibular localisation. Macroscopically 3 tumours were cystic,2 cases were firm and brownish. Histologically,5 cases had a conventional ameloblastoma including 4 cases in its follicular form and 1 case in its acanthomatous form. The 6th case had unicystic ameloblastoma. The patient, who presented with dual tumour localization, had both a macrocystic ameloblastoma and a conventional follicular ameloblastoma infiltrating the mandibular bone.

Conclusion: Ameloblastoma expands from the odontogenic epithelium. The most frequently reported aspect is cystic (90% of cases for 75% of cases in our work). The architectural variants are in order of frequency - both in the literature and in our results -: follicular, plexiform, acanthomatous type and granular cell type. It is a benign tumour with local development which only very exceptionally degenerates. The treatment is exclusively surgical, justifying a large excision to avoid recurrences which require uncertain and mutilating salvage interventions.

PS-11-006

The importance of EGFR gene amplification in the malign salivary gland tumours

F. Bir*, Y. Arman Karakaya, Ö. Ateşçi, E. Mengi, A. Yaren, C.O. Kara, P.B. Baltalarlı

*Pamukkale University, Turkey

Background & objectives: Epidermal growth factor (EGFR) is an important treatment target in several cancers. We aimed to investigate the contribution of this marker to the prognosis of salivary gland tumours by analysing the EGFR amplification status of the salivary gland tumour.

Methods: Forty-four cases of salivary gland carcinoma reported at Pamukkale University between 2001-2021 were included in the study. These tumours were re-evaluated according to the 2017 WHO classification. EGFR amplification was examined in these cases with the FISH method. Amplification rate ≥ 15% in tumour cells was considered positive.

Results: Of the 44 salivary gland carcinomas, 21 were adenoid cystic carcinomas, 20 were mucoepidermoid carcinomas, 2 were acinic cell carcinomas, and 1 was salivary gland ductus carcinoma. EGFR amplification was observed in a total of 6(13.6%); 3(6.8%) of them were mucoepidermoid carcinoma, 2(4.5%) were adenoid cystic carcinoma, 1(2.3%) was salivary. gland ductus carcinoma(p=0.072). EGFR amplification positivity was seen in 67%(4/6) of stage 1 cases, 83%(5/6) in cases <65 years old, and 67%(4/6) in women. The disease-free survival time was shorter in male patients(p=0.001), patients with neck dissection(p=0.007), patients with metastatic lymph nodes(p=0.011) and angiolymphatic invasion(p=0.013). Mortality rate was higher in patients with EGFR amplification(p=0.032).

Conclusion: EGFR mutations in salivary gland tumours are rare, however, EGFR amplification has been reported in the literature at a rate of 5-14%. We found the EGFR amplification as 13,6% in this study. EGFR amplification is common in early-stage and female patients under 65 years of age and the mortality rate is higher in these cases. Our findings should be supported by more studies.

PS-11-007

Synchronous adenolipoma and follicular variant papillary carcinoma of thyroid: a case report of a rare condition

G. Carvalho*, T.N. Albuquerque Gomes Nogueira, J. Souza, G. Holanda Maia, A. Lobo Ramos, M. Camelo Ferreira, R. Faustino de Araújo Neto, M. de Lima Pinto, D.I. Magno Cavalcante

*Federal University of Ceará, Brazil

Background & objectives: Adenolipomas are rare benign neoplasms composed of mature adipose tissue and glandular elements. We report a case of a adenolipoma coexisting with follicular variant papillary thyroid carcinoma.

Methods: A 55-year-old woman presented with multinodular and enlarged thyroid in neck ultrasound. Computed tomography revealed a thyroid with heterogeneous parenchyma by nodules, the largest in the right lobe, with apparent fat content, measuring 2.0 cm. Fine needle aspiration (FNA) of one of the nodules was suspicious for papillary thyroid carcinoma (Bethesda category V). The patient underwent total thyroidectomy.

Results: Gross examination revealed a nodular and bumpy thyroid gland. Cut surface featuring a dull and whitish nodule with 1,2 x 1,0 x 0,9 cm, in right lobe. There were brown gelatinous colloid nodules exhibiting variegated size, the largest measuring 2,0 cm in greatest dimension, situated in the same lobe and showing soft and yellowish areas. Histologically, the features were consistent with follicular variant papillary carcinoma and adenolipoma in addition to multinodular hyperplasia.

Conclusion: Only few cases of lipoadenomas of the thyroid have been reported in the literature. Its origin is unknown; a number of authors explain it as an abnormality arising during thyroid encapsulating or from fibroblast metaplasia following hypoxia. The coexistence of adenolipoma and follicular variant papillary thyroid carcinoma as different lesions is a rare occurrence. However, it doesn't complicates the evolution and treatment. Surgical resection of thyroid adenolipoma is curative with no recurrence or malignant potential.

PS-11-008

Relationship of E-cadherin, Beta-catenin, N-cadherin, ZEB1 and αSMA as epithelial mesenchymal transition markers with prognostic factors in early and advanced stage laryngeal squamous cell carcinomas

U. Kucuk, S. Ekmekci*, C.K. Talu, Y. Pekcevik, I. Cukurova

*University of Health Sciences Turkey, Tepecik Research and Training Hospital, Department of Pathology, Turkey

Background & objectives: To investigate the relationship between E-cadherin, Beta-catenin, N-cadherin, ZEB1 and αSMA as epithelial mesenchymal transformation markers with tumour stage, lymph node metastasis and overall survival in laryngeal squamous cell carcinomas.

Methods: A total of 100 cases diagnosed with laryngeal squamous cell carcinomas in our hospital between 2013-2020 were included in the study. Data about lymphovascular invasion, perineural invasion, necrosis and lymph node metastasis were recorded by evaluating hematoxylin- eosin stained slides. Markers of E-cadherin, beta-catenin, N-cadherin, ZEB1 and αSMA were applied to the sections prepared from paraffin blocks of tumour samples.

Results: Ninety-five male and five female patients were included in the study, and 38 of them exited. The average overall survival time of the cases was 35.8 months. A significant relationship was observed between overall survival with advanced tumour stage, presence of lymph node metastasis and perineural invasion. A significant relationship was found between increased tumour Zeb1 expression and advanced tumour stage. In univariate and multivariate analyses, a significant negative relationship with overall survival, and increased Zeb1 expression in tumour and tumour stroma was seen. Any relationship was not observed between E-cadherin, beta-catenin, N-cadherin and αSMA and overall survival.

Conclusion: Among the epithelial mesenchymal transformation markers we evaluated in our study, it was seen that Zeb1, which is an epithelial mesenchymal transformation transcription factor, is associated with tumour stage, lymph node metastasis, and overall survival. Remarkably, Zeb1 expression observed in tumour stroma was also significant for overall survival. Any similar data reported for laryngeal squamous cell carcinomas have not been encountered in the literature, and it was thought that it would be appropriate to support our findings with further studies to be performed on this subject.

PS-11-009

Primary laryngeal angiosarcoma with neuroendocrine marker expression, metastatic to lymph node: a case report

A. Elwy*, M. Maher, N. Magdy

*Pathology Department, South Egypt Cancer Institute, Assiut University, Egypt; Shefaa Al-Orman Oncology Hospital, Luxor, Egypt

Background & objectives: Primary laryngeal angiosarcoma (AS) is among the rarest laryngeal sarcomas. AS is an aggressive vascular tumour that usually metastasizes via the hematogenous route, while lymphatic spread is uncommon. A few recently reported AS cases showed an aberrant neuroendocrine marker expression.

Methods: A 37-year-old male patient complained of left side neck swelling. Computed Tomography revealed small soft tissue mass at the left pyriform fossa and ipsilateral cervical lymphadenopathy. The patient underwent biopsy of the mass and lymph node and diagnosed elsewhere as neuroendocrine carcinoma with lymph node metastasis. The patient admitted to the oncology-clinic and the paraffin blocks were requested for review.

Results: Microscopically, the pyriform fossa mass biopsy showed fragments lined focally by stratified squamous epithelium infiltrated by malignant neoplasm, formed of anastomosing vascular channels lined by high-grade multi-layered endothelial cells. The lymph node biopsy revealed a metastatic neoplasm, exhibiting a biphasic morphology. The predominant pattern was solid sheets of highly pleomorphic epithelioid cells, and the other pattern was similar to the mass biopsy. Immunohistochemically, the tumour cells of both biopsies were diffusely positive for CD31 and ERG, while negative for CD34. However, the epithelioid cells in the lymph node were positive for CK, Synaptophysin and CD56. The final diagnosis was laryngeal epithelioid angiosarcoma with neuroendocrine differentiation and ipsilateral cervical nodal metastasis.

Conclusion: To the best of our knowledge, this is the first reported case of angiosarcoma combining three rare conditions; the unusual laryngeal location, the initial presentation by nodal metastases and the aberrant NE marker expression. This unusual immunoexpression represents a challenging diagnostic pitfall that pathologists should be aware of to avoid misdiagnosing AS, especially the epithelioid variant, as poorly differentiated neuroendocrine carcinoma.

PS-11-010

Carcinoma ex pleomorphic adenoma. A clinicopathological study in a 10-year period

G. Galanopoulos*, L. Karelis, E. Souka, G. Stanc, H. Trihia, C. Valavanis, O. Tzaida

*Metaxa Cancer Hospital, Pathology Department, Greece

Background & objectives: Carcinoma ex pleomorphic adenoma (CXPA) reported in the literature ranges from 1.5% to 14% of all salivary gland tumours. We study the frequency of CXPA recorded in the Department of Pathology of Metaxas Cancer Hospital in a 10-year period.

Methods: Over the last decade, 22 cases of malignant tumours were identified among 276 salivary gland specimens examined. The age range was between 34 to 78 years.

Results: Out of these 22 cases, 4 of them consisted of CXPA and the rest were distributed as mucoepidermoid (6), adenoid cystic (5), acinic cell (1), squamous cell carcinoma (2), adenocarcinoma NOS (3), and cystadenocarcinoma (1). Regarding the CXPA cases, two of them showed histopathological features of adenoid cystic carcinoma and the rest were myoepithelial carcinomas. In all cases residual element of pleomorphic adenoma (PA) was demonstrated at least in small part of the tumours.

Conclusion: PA is the most common salivary gland tumour, representing about 50% of all primary salivary gland neoplasms, followed by Warthin tumour. Although local recurrence is usual, a malignant transformation is rare. The incidence of malignant salivary gland tumours in our material is 8% with CXPA accounting for only 1.5%. The mean patient age was 67 years. Since various carcinoma subtypes can be encountered, misdiagnosis is common.

PS-11-011

The diagnostic value of the extemporaneous examination in thyroid surgery

I. Helal*, A. Hmidi, F. Khanchel, M. Ben Thayer, E. Ben Brahim, R. Jouini, A. Chadli-Debbiche

*Habib Thameur's Hospital, Tunisia

Background & objectives: The extemporaneous-examination (EE) allows to obtain a rapid diagnosis of benignity or malignancy of Thyroid nodules and to avoid abusive initial surgery. However, its efficiency and limits remain controversial. Our study aimed to evaluate the diagnostic value of the EE.

Methods: We conducted a retrospective study, carried out from January 2016 to June 2017, of EE performed on thyroid resection specimens at Habib Thameur hospital. We compared the results of the EE to final histological examination (FHE). The diagnostic value of EE was evaluated by calculating sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV).

Results: 319 EE have been included, 190 (59.5%) were benign, 41 (13%) were malignant and in 88 of the cases (27.5%) the response was delayed. Among the 190 nodules considered benign on EE, 168 were truly benign on EHD while 22 results were malignant. Among the 41 EE malignant lesions, 39 were carcinomas: papillary (91%), vesicular (6.5%), medullary (1%) and undifferentiated (1%). The specificity was 98.8% with a PPV of 95.12% and the sensitivity was 64% with a NPV of 88.4%. The delayed results were benign in 64%, malignant in 34% and lesions of uncertain malignancy in 2%. The diagnostic efficiency of EE was 65%.

Conclusion: Our study confirmed the perfect sensitivity of the EE with excellent VPN. However, its low specificity is mainly linked to the diagnostic difficulties of encapsulated tumours with vesicular architecture and to technical problems such as difficulty in handling fresh tissue.

PS-11-012

Single institutional morphological study of HNSCC focused on perinerual invasion

P. Hurník*, V. Zidlik, D. Ziak, M. Sporkova, J. Stembirek, Z. Cermakova, O. Motyka, B. Putnova, M. Buchtova

*Department of Pathology, University Hospital of Ostrava, Faculty of Medicine, University of Ostrava, Faculty of Medicine, Masaryk University Brno, Czech Republic

Background & objectives: Head and neck squamous cell carcinoma (HNSCC) is a cancer with squamous differentiation arising from mucosal epithelium in the oral cavity, tongue and oropharynx. It is the 6th most common cancer in the world with mortality 4-6/100000 people.

Methods: We have retrospectively analysed cases of 487 patients in age 29-85 years with HNSCC who underwent curative surgery with bilateral cervical block dissection in period 2006-2016. We focused on the evaluation of stage (AJCC2017), nodal status, PNI, BVI and LVI. Moreover, we added new parameters such as the mode of invasion, the worst pattern of invasion, tumour budding a lymphocyte infiltration.

Results: Most of our cases exhibited 3rd degree of MOI (288cases) or 4th degree of WPOI (212cases). PNI was present with an increasing frequency in both of these classifications of tumour growth - MOI3: 17%, MOI4: 32,6%, MOI5: 50% and WPOI3: 12,9%, WPOI4: 26,9% WPOI5: 55,6%. Tumour budding (LG: less than 5 buds, IMG: 5-10 buds, HG: more than 10 buds) correlated with the incidence of PNI, 85% HNSCC with PNI developed HG budding. Brisk (49,5%) and non-brisk (42,9%) immune response presented by TIL correlated with these morphological signs. Moreover, we evaluated the morphology of PNI with following incidence: type A(1%), type B(58,6%), type C(31%), type D(6%), type E(6%), type F(0%).

Conclusion: Here, we focused mostly on PNI occurrence, morphology of PNI and other negative morphological prognostic factors in HNSCC patients. Our study revealed an association between PNI and other analysed common diagnostic factors as well as newly selected morphological features. Next, we plan to focus on cellular and molecular processes accompanying the initiation of PNI with aim to uncover main cancer characteristics and possible involvement of neural chemoattractant.

Funding: Supported by Ministry of Health of Czech Republic, grant nr. AZV NV19-08-00383. All rights reserved.

PS-11-013

Cribriform adenocarcinoma of the minor salivary glands: an entity on the rise

D. João*, A. Sanches, C. Meireles

*Department of Anatomic Pathology, Centro Hospitalar de Vila Nova de Gaia/Espinho, Porto, Portugal

Background & objectives: Cribriform adenocarcinoma of the minor salivary glands, or cribriform variant of polymorphous adenocarcinoma according to the current WHO classification, is a rare tumour of the head and neck, with increasing evidence of histopathological and prognostic features distinct from conventional polymorphous adenocarcinoma.

Methods: We present the case of a 91-year-old male without relevant medical history. He was referred to our institution due to a painless tumefaction in the mouth floor, detected by the caretakers two days before. Physical examination revealed a well-defined, mobile and elastic tumour, measuring up to 4cm and covered by intact but erythematous and papillomatous mucosa, which was biopsied.

Results: On histopathological examination, a malignant epithelial neoplasm was found within the submucosa, lined by preserved epithelium. The tumour was comprised of solid or microcystic nests of neoplastic cells, displaying peripheral retraction artifact and a fibrous surrounding stroma. Nuclei were round, clarified and with vesicular chromatin, sometimes with nuclear crowding. Immunostaining showed heterogeneous positivity for CK5/6 and CK7 and diffuse and strong positivity for S100 and SOX10, in the absence of expression of SMA, D2-40, p40 and TTF-1. From these findings, the patient was diagnosed with cribriform variant of polymorphous adenocarcinoma. This is a rare and still mysterious entity and we reviewed the most recent findings in medical literature.

Conclusion: There is still much debate if the cribriform adenocarcinoma of the minor salivary glands is a separate entity from polymorphous adenocarcinoma, a variant or if they are both part of a same morphologic spectrum. Both harbour genetic changes in the PRKD1, PRKD2 and PRKD3 genes, although these are essentially translocations in the former and somatic point mutations in the latter. Most importantly, cribriform adenocarcinoma metastasizes more frequently to the cervical lymph nodes (50% at presentation), requiring lymph node dissection.

PS-11-014

HPV-related multiphenotypic sinonasal carcinoma: a case report and literature review

D. João*, M. Jácome, A.S. Pires-Luís, A. Sanches, C. Meireles

*Department of Anatomic Pathology, Centro Hospitalar de Vila Nova de Gaia/Espinho, Porto, Portugal

Background & objectives: Human papillomavirus (HPV)-related multiphenotypic sinonasal carcinoma is a recently described tumour of the sinonasal tract which displays both characteristics of salivary gland and surface-derived carcinoma and is linked to high-risk HPV.

Methods: We report the case of an 86-year-old male with a destructive lesion involving the hard palate, maxillary sinus, nasal fossa and left frontal sinus. Histological, immunohistochemical and molecular testing were performed on the biopsy specimen. This case report includes a review of the most recent medical literature.

Results: Morphological evaluation revealed a basaloid neoplasm infiltrating the mucosa, with a nested and cribriform architecture. It was comprised of cells with round, hyperchromatic and vesicular nuclei and scarce eosinophilic cytoplasm. There were abundant mitoses and apoptotic bodies. Immunostaining was positive for p16, CK5/6, CK7, BerEP4, Bcl2 and SOX10 and negative for S100, GFAP, calponin, synaptophysin, calretinin and TTF1. Molecular testing detected the presence of high-risk HPV. Based on these findings, the patient was diagnosed with HPV-related multiphenotypic sinonasal carcinoma.

Conclusion: Previously known as HPV-related carcinoma with adenoid cystic carcinoma-like features, this entity is a potential diagnostic pitfall with high grade adenoid cystic carcinoma. Morphologic range is wider than initially thought and not all cases display basaloid features. Although p16 is a useful screening tool, definitive diagnosis requires HPV-specific testing. Correct diagnosis is crucial, since despite frequent presentation at high stages and exhibition of high-grade cytological features, its behaviour is remarkably indolent, with rare metastasization and no reported tumour-related deaths.

PS-11-015

Effect of blood corticosterone concentration on mast cell degranulation in the mesentery in rats after maxillofacial surgical trauma

I. Kastyro*, M. Kostyaeva, S. Dragunova, A. Kosyreva

*Peoples’ Friendship University of Russia, Russia

Background & objectives: The release of glucocorticoids by the adrenal cortex reduces the immune response, but degranulation of mast cells (MC) can increase, provoking the release of inflammatory mediators. Objective. To study the relationship between MC degranulation and blood corticosterone concentration after trauma to rats nasal septum (NS).

Methods: Wistar rats were simulated with septoplasty using zoletil 100 (5 rats). 5rats were a control group (CG). After surgery, the rats were determined the concentration of corticosterone on the 2nd, 4th, 6th days and then sacrificed, stained the mesentery on a slide with toluidine blue. mast cells with varying degrees of degranulation (0-3) were counted in 20 visual fields.

Results: On the 2nd, 4th, 6th days after surgery, the number of mast cells of type 0 significantly decreased (24.12±2.88; 13.22±1.87;14.88±2.84), compared with the control group (CG) (40.45 ± 2.21) (p<0.001). The number of MC type II on the 4th (2.87±0.31) and 6th (2.27±0.47) days decreased, but the number of MC type III increased (1.87±0.11 and 1.61±0.1, respectively), compared with the control (type II - 1.3±0.17; type III - 0.8±0.13). After septoplasty, compared with CG (38.56±2.12 ng/ml), corticosterone increased on day 2, and on day 4 (122.55±5.38 ng/ml) and 6 (118.35±5,69ng/ml) decreased and maintained its stable blood concentration (p<0.001).

Conclusion: An increase in the degree of mast cell degranulation coincides with an increase in the concentration of corticosterone in the blood plasma in rats 4-6 days after surgery. When simulating a surgical trauma in the maxillofacial region, the release of glucocorticoids can provoke the development of general inflammation, including in the mesentery, which is confirmed by an increase in the number of mast cells of grade III degranulation.

PS-11-016

Immunohistochemical criteria for pathological transformation of cells of nasal cavity mucous membrane in case of recurrent inverted papillomas

I. Korshunova, V. Popadyuk, A. Chernolev, I. Kastyro*

*Peoples’ Friendship University of Russia, Russia

Background & objectives: In 8-10% of cases inverted papillomas (IP) in situ, papillomavirus DNA(HPV) is detected. Aim. Identification of immunohistochemical criteria for pathological cells transformation of nasal cavity (NC) mucous membrane (MM) in case of recurrent IP using expression of the Ki-67 marker.

Methods: Materials and methods. Ki-67 & HPV-positive cells were determined in NC mucosa. As an indicator of proliferative activity, the Ki-67 proliferation index was used, which was determined in each row of cells by fractions of stained nuclei, expressed in %.

Results: Dysplastic processes of MM surrounding the IP at an average distance of up to 0.5 cm and identified in all our observations were characterized by a general proliferative activity of epithelial cells of 17.25±4.11%, which was higher (p<0.01) than proliferation cells in unchanged epithelium, with hyperplasia of MM and with IP. Most immunopositive cells were localized in 2nd row of cells, with recurring IP Ki-67-positive cells were found in the basal and parabasal layers. HPV-positive immunostaining was detected in individual nuclei of infected cells of the basal and parabasal layers. HPV elements were detected in actively proliferating basal and parabasal IP layers and their relapses.

Conclusion: HPV elements in IP and their relapses were identified. This indicates their role in the formation and relapses of nasal cavity IP. In all studied preparations, pronounced Ki-67 expression was observed in the nuclei of proliferating cells.

PS-11-017

Comparison of morphological changes during modeling of bone tissue damage and after implantation of a titanium implant in the upper jaw in rats.

S. Dragunova, M. Kostyaeva, I. Kastyro*, V. Popadyuk

*Peoples’ Friendship University of Russia, Russia

Background & objectives: Morphological changes against the background of inflammation during manipulations in dental surgery can lead to various complications-pain, implant rejection, etc. Aims. To compare morphological changes during modelling of bone tissue damage and during implantation of a titanium implant in the rats maxilla.

Methods: Under anaesthesia with zoletil 100 to 30rats, a bone socket was formed between the incisors and molars on one side. In 1group(15 rats),implantation was not performed, and in 2group(15rats), titanium implants were screwed in. Five animals from both groups were sacrificed on days 2,4,6 after surgery, the damaged parts were placed in a decalcifying solution, and then were stained with H&E.

Results: Around the dead tissues in both groups, there is a reactive inflammation limiting them. In the demarcation zone, full-blooded vessels, oedema, leukocyte shaft, multiplying cells of connective tissue, which is involved in the formation of the demarcation shaft, were found. The collagen fibres were swollen and impregnated with fibrin, forming dense homogeneous masses.

Conclusion: Damage to bone tissue, both with and without implantation, leads to the development of typical reactions of necrosis and inflammation. The simple application of damage to the upper jaw with a boron in rats can be considered as an analogue of the implantation model.

PS-11-018

Case report: potential drivers of metastatic progression in CPGL

A. Kobelyatskaya*, A. Snezhkina, G. Krasnov, I. Bakhtogarimov, Y. Vershinina, D. Kalinin, A. Golovyuk, V. Pavlov, A. Kudryavtseva

*Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia

Background & objectives: A 38-year-old female was diagnosed with a left carotid paraganglioma (CPGL). The patient had undergone surgery for tumour resection. Histopathology of the resected specimen was consistent with paraganglioma of carotid origin with lymph node metastasis.

Methods: We performed exome sequencing of tumour, lymph node metastasis, and normal tissue from the patient. Exome libraries were prepared using the TruSeq DNA Exome Kit (Illumina, USA). Paired-end sequencing of libraries (76x2) was performed on an Illumina NextSeq 500 System. The search for pathogenic/likely pathogenic variants was carried out using GATK HaplotypeCaller.

Results: Exome analysis revealed no pathogenic/likely pathogenic variants in known susceptibility genes for paragangliomas/pheochromocytomas (RET, FH, VHL, NF1, SDHx, SDHAF2, TMEM127, MAX, EGLN1, HIF2A, MET, and KIF1B). Somatic likely pathogenic frameshift mutations in the OR2T7, CTU2, LMTK3, HLA-DRB1, CBS, and FAM83H genes, as well as missense mutation in the EIF2AK3 gene, were found in both tumour and metastasis samples. Notably, in the metastasis sample, we detected variants in many genes that were not mutated in the primary tumour.

Conclusion: According to the literature, one of the main factors, indicating risk for metastatic paragangliomas/pheochromocytomas, is the SDHB mutation. However, in the study case, we have not identified variants in any known susceptibility genes. In primary tumour and metastasis, we detected common somatic likely pathogenic variants in six genes, when much more novel genes were mutated only in metastasis. Identified genes affected by metastasis-specific mutations and mutations shared between primary tumours and metastases can be potential drivers of metastatic progression.

This work was performed using the equipment of EIMB RAS “Genome” centre (http://www.eimb.ru/ru1/ckp/ccu_genome_c.php).

Funding: This work was financially supported by the Russian Science Foundation, grant no. 21-14-00353.

PS-11-019

Somatic SDHx variants in patients with vagal paragangliomas

A. Kobelyatskaya*, V. Pavlov, G. Krasnov, M. Fedorova, D. Kalinin, A. Golovyuk, A. Snezhkina, A. Kudryavtseva

*Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia

Background & objectives: Vagal paragangliomas (VPGLs) are rare tumours of the head and neck that arise from paraganglionic tissue surrounding the vagus nerve. More than twenty susceptibility genes associated with the PGLs are currently known. However, oncogenic somatic events have been poorly investigated.

Methods: The exome sequencing and analysis of 16 tumour and normal tissues derived from the patients with VPGLs were performed. Exome libraries were prepared using the TruSeq DNA Exome Kit (Illumina, USA) and were sequenced on an Illumina NextSeq 500 System with the paired-end mode, 76x2 reads. Somatic pathogenic/likely pathogenic variants were identified using GATK HaplotypeCaller.

Results: We analysed 16 exomes from patients with VPGLs on the presence of somatic mutations in the SDHx genes. Three somatic likely pathogenic variants were revealed in the SDHB gene in a patient: frameshift variant NM_003000: c.308_309insTAAG, p.M103fs (chr1: 17355209), missense variant NM_003000: c.A307G, p.M103V (chr1: 17355211), and frameshift variant NM_003000: c.304_305insATGAT, p.A102fs (chr1: 17355213). Pathogenicity of the missense variant was predicted by all in silico prediction tools (PolyPhen2, LRT, SIFT, and others); the variant was also characterized by a high conservation score according to PhastCons.

Conclusion: Mutations in the SDHx genes, encoding for subunits of succinate dehydrogenase, are typically associated with the hereditary PGLs when somatic variants in these genes are very rare events. In the study cohort, we found one patient with somatic likely pathogenic variants in the SDHB gene. The patient did not carry any germline variants in the known susceptibility genes. Thus, these somatic variants appear to be a driver event in the development of the tumour.

This work was performed using the equipment of EIMB RAS “Genome”center (http://www.eimb.ru/ru1/ckp/ccu_genome_c.php).

Funding: This work was financially supported by the Russian Science Foundation, grant no. 19-15-00419.

PS-11-020

Expression of CK 17 in squamous laryngeal carcinomas

D. Koumoundourou*, N. Mastronikolis, S. Lygeros, P. Ravazoula

*Patras University Hospital Pathology Department, Greece

Background & objectives: Cytokeratins are proteins of the cytoskeleton with diverse expression in several epithelial neoplasms.

The purpose of the present study is the detection of CK17 expression in squamous laryngeal carcinomas and its correlation with several clinicopathological parameters.

Methods: CK17 expression was studied in 58 cases of squamous laryngeal carcinomas (24,1% Grade I, 50% Grade II, and 25,9% Grade III) For every patient included in the study there was a mean follow up time of 30 months during which 27 (46,6%) patients died from their disease. Statistical analysis was interpreted using SPSS16 for windows.

Results: CK17 expression was strongly correlated with tumour Grade (p=0,028) with loss of its expression in high-Grade tumours. In multivariate (Cox regression) analysis the correlation between absence of CK17 and adverse patients’ outcome approached borderline (p=0,056).

There was no significant association between the presence of CK17 with either tumour size or positive cervical lymph nodes. The adjacent normal epithelium was CK17 negative while low expression of the protein was detected in dysplastic areas.

Conclusion: Our results agree with the existent literature which suggests that high expression of CK17 predicts poor patients' prognosis. Our findings indicate that CK17 is associated with early malignant transformation and might be a suitable marker for detecting the presence of dysplasia. Furthermore, the protein may be a prognostic factor in squamous carcinomas since its expression is lost during tumour progression and may have a key role in predicting worse patients' outcome.

PS-11-021

Dysgenetic polycystic disease of the parotid gland: a rare case report

J. Madeira*, J. Gama, C. Faria, M.B. Pimentão, M.J. Julião, M.A. Cipriano

*Serviço de Anatomia Patológica, Centro Hospitalar e Universtário de Coimbra, Portugal

Background & objectives: Dysgenetic polycystic disease (DPD) is a benign rare cystic lesion arising from distal ductal system salivary glands, primarily affecting the parotid glands, mainly the superficial lobe. It is more prevalent seen in young females, usually with bilateral involvement.

Methods: We report a case of a 48-year-old woman with complains of a slowly progressive and non-painful bilateral parotid gland swelling, posteriorly to the angle of the mandible, since childhood. Recently she complained of a sudden increase in size and associated dull, aching and continuous pain.

Results: Control magnetic resonance imaging (MRI) scan revealed bilateral enlarged parotid glands, almost completely occupied by multiple cysts, some with septa and others confluent, of “pure content”, the largest on the left side with 4.4 cm. Multiple fine needle aspiration (FNA) were performed always with the diagnosis of simple cyst (The Milan System - category II). She was submitted to partial parotidectomy and histopathological evaluation revealed multiple cysts of varying sizes some interconnected, replacing the parotid parenchyma with lobular architecture preserved. The cysts were lined by a flattened cuboidal epithelium with no atypia. Short, finger-like epithelial septations extended into lumen were found, as well as proteinaceous, eosinophilic and calcified material.

Conclusion: The diagnosis of DPD of parotid gland was made. Cystic lesions in the parotid gland may represent an array of diverse entities with distinct biological behaviour and other cystic lesions must be considered in the differential diagnosis. DPD is a unique entity that resembling other polycystic diseases that affect the kidneys and pancreas, however there seems to be no association between them. Long-term follow-up is required to rule out recurrence and to screen for the involvement of other salivary glands.

PS-11-022

Human papilloma virus type 16 expression in pleomorphic adenomas and adjacent tissue of salivary glands

M. Myroshnychenko*, I. Brodetskyi, O. Dyadyk, V. Malanchuk

*Kharkiv National Medical University, Ukraine

Background & objectives: Pleomorphic adenoma (PA) is one of the salivary gland (SG) tumours. The role of human papilloma virus (HPV) in this tumour development is ambiguous. The objective is to determine the HPV type 16 expression in PA and SG adjacent tissue.

Methods: Two groups were formed. Group 1 (G 1) included 4 cases with an intact SG (autopsy material). Group 2 (G 2) included 30 cases (surgical material) with SG PA of mesenchymal (n=15), mixed (n=15) and epithelial (n=5) histological variants. Immunohistochemical reaction (IHCR) was performed, using mouse monoclonal antibody (MCA) to HPV type 16 (clone CAMVIR-1, «Diagnostic BioSystems», USA).

Results: IHCR was negative in G 1 and positive in G 2 in 26 cases (86.7%). In G 2 nuclear expression of MCA to HPV type 16 was found in tumour parenchyma (epithelial cells formed nests and cords, solid, trabecular, cystic, glandular, ductal, tubular structures; myoepithelial cells) and stroma (vascular endotheliocytes; immune and fibroblastic cells; myxoid and mucoid zones cells). In adjacent SG tissue, the ductal epithelial cells, myoepithelial cells expressed this MCA. IHCR in PA and SG adjacent tissue was the most pronounced, pronounced, moderately pronounced, respectively, in epithelial, mixed, mesenchymal tumour variants. In all PA variants, IHCR was less pronounced in SG adjacent tissue compared to PA tissue.

Conclusion: The positive expression (in 86.7% of cases) of MCA to HPV type 16 in pleomorphic adenomas tissue and adjacent tissue of salivary glands indicates that HPV type 16 may be one of the causes of such tumour development. The results obtained by the authors are of great therapeutic and prognostic significance.

PS-11-024

SALL4 expression in oral squamous cell carcinoma and its possible involvement in oral carcinogenesis

A. Ouban*

*Alfaisal Uni. College of Medicine, Saudi Arabia

Background & objectives: SALL4 plays important roles in cancer. This study analyses the expression of SALL4 in oral squamous cell carcinoma (OSCC), link it to characteristics of OSCC patients and assess the expression of a closely-linked protein, Beta-catenin, in the same population.

Methods: This study analysed the expression of SALL4, using immunohistochemistry, in a tissue microarray of 50 oral squamous cell carcinomas (OSCCs) and 10 normal oral mucosal tissue from the oral cavity. Clinic-pathological parameters of the patients were assessed in relations to SALL4 expression in those tissues. Moreover, an Epithelial-Mesenchymal Transition (EMT) phenomenon-linked protein, Beta-catenin’s expression was analysed in the same microarray.

Results: A significant majority of oral squamous cell cancers exhibited positive expression of SALL4 protein. All of the OSCC tumours expressed SALL4 in their cytoplasm and nuclei. The overall majority of those same tumours exhibited an aberrant expression of Beta-catenin, where a shift of expression of Beta-catenin from their membranes to the cytoplasm and nuclei was noted. This study presents evidence of an aberrant co-expression of SALL4 and beta-catenin in OSCC cells. With the current findings and with past evidence of SALL4 modulating the Wingless/Wnt/Beta-catenin pathway in other tumours, it suggests a similar regulatory role for SALL4 in OSCCs.

Conclusion: SALL4 is a uniquely qualified candidate for therapeutic intervention in OSCCs, first because it is missing in normal adult cells, and secondly because of its triple involvement in OSCC development, EMT phenomenon in OSCCs and tumour’s stemness. This may provide a rare opportunity to roll back the dismal course of this disease.

PS-11-025

The role of mu (μ) and kappa (k) opioid receptors in the carcinogenesis and prognosis of oral squamous cell carcinoma: an immunohistochemistry retrospective study

M.E. Porto*, M.P.S. S. Cunha, T. S. Dantas, F. B. Sousa, P. G. B. Silva, A.E. S. O. Lima, A. C. Andrade, I. S. Guedes

*School of Medicine, University of Fortaleza, Brazil

Background & objectives: Squamous Cell Carcinoma (SCC) is the mouth’s most prevalent tumour. Opioids may be involved in carcinogenesis while helping symptoms management in advanced cases. The objective is to analyse the influence of opioids receptors in the progression of oral cavity carcinomas.

Methods: Cross-sectional, observational and retrospective study which considered 25 samples of oral mucosa from healthy patients, 25 samples of squamous dysplasia and 50 samples of SCC. Tissue Microarray was performed for immunohistochemistry with anti-receptor μOpioid and kOpioid antibodies. Immunostaining was evaluated with ImageJ® software. Socio-demographic and survival data were analysed from medical records.

Results: There was an increase in immunoexpression of both μOpioid and kOpioid receptors in dysplasia and SCC. A lower expression of μOpioid was observed in T1 tumours when compared to the other T stages. Patients who died showed a more prominent immunodetection of kOpiod in the cytoplasm, suggesting that the survival rate of patients with low cytoplasmic expression for κOpioid is greater than in those with high expression. Clinical characteristics such as sex, age, smoking history, alcohol consumption and site of the primary tumour didn't influence the immunoexpression for opioid receptors.

Conclusion: This was the first study to characterize the immunoexpression of opioid receptors in the healthy mucosa compared to dysplasia and oral SCC samples. The study demonstrated an increase of the receptors in SCC and the influence of the Kappa receptor on patients' survival expectations. Therefore, it is necessary to study the mechanisms by which these receptors act in carcinogenesis and tumour progression.

PS-11-026

Sialolithiasis: biophysical studying of calculi

O. Diachenko, Y. Kuzenko, A. Kravchenia, M. Lyndin, V. Sikora, A. Romaniuk*

*Sumy State University, Ukraine

Background & objectives: The aim is to study the biophysical features of stone formation in structurally altered tissues of the salivary glands.

Methods: In our investigation 20 tissue samples of SG with biomineral formations were used in the study by histological method, scanning electron microscopy, statistical analysis.

Results: Sialolites of the salivary glands had an elongated oval shape, ranging in size from 0.3 to 2.0 cm in the largest dimension. Biomineral formations often had a whitish-grey colour, although there were stones of yellowish-brown and brown shades. Some small stones were found in the parenchyma of the salivary gland. The average mineral content in sialolites averaged 64.33%. The study of the relief of the sialolites section surface showed a circular deposition of mineral matter on the periphery of the calculus and a complex pattern of mineralization layers in its core. The following composition of sialolites was determined by electron microscopy: Ca-11.66%, P-6.39%, Na-0.47%, Mg-0.23%, S-0.14%.

Conclusion: Formation of SG stones occurs on the background of chronic inflammation and structural rearrangement of glandular tissue.

According to the results of factor analysis, the connection between the presence of benign or malignant tumours and the process of calcification (0.83) in structurally altered tissues of the salivary gland was defined.

The stoichiometric ratio of calcium and phosphorus is 1.82.

PS-11-027

Malignant salivary gland tumours in South Tunisia: a clinicopathological study of 40 cases

I. Saguem*, M. Walha, M. Mellouli, S. Makni, C. Chaari, N. Gouia, T. Boudawara, R. Kallel

*Habib Bourguiba University Hospital, Sfax, Tunisia

Background & objectives: Malignant salivary gland tumours (MSGTs) are very rare representing 3% of all cancers of the head and neck. They greatly vary in origin, subtype, and behaviour. The purpose of this study is to review the clinicopathological features of MSGTs.

Methods: Forty cases of MSGTs diagnosed in our department of pathology, were collected from January 2010 to December 2020. These tumours represented 20.9% of the total number of salivary gland tumours. An analysis of the clinical and histological data was carried out in all cases.

Results: The mean age of patients was 52.72 years (16 - 86 years). The parotid gland was the commonest location (21 cases, 52.5%). The submandibular and sublingual glands accounted for 3 cases (7.5%) each, and minor salivary glands for 8 cases (20%). On histological examination, adenoid cystic carcinoma was the most frequent type accounting for 9 cases (22.5%) followed by acinic cell carcinoma in 8 cases (20%), mucoepidermoid carcinoma in 7 cases (17.5%), carcinoma ex pleomorphic adenoma in 6 cases (15%) and polymorphous carcinoma in 5 cases (12.5%). Adenocarcinoma NOS, lymphoepithelial carcinoma and poorly differentiated carcinoma were found each in 2 cases (5%) and salivary duct carcinoma in 1 case (2.5%).

Conclusion: Malignant salivary gland tumours are one of the most difficult areas of diagnostic pathology, with significant morphological diversity and many overlapping features. The principal hurdle in the management of these tumours is the difficulty in distinguishing them from benign tumours. They demonstrate an unpredictable clinical course marked by frequent locoregional recurrence and distant metastasis.

PS-11-028

Clinicopathological features and mutation of BRAFV600E in papillary thyroid carcinoma

O. Suren*, M. Malchinkhuu, Z. Altangerel, M. Dawaajargal, P. Munkhuu, O. Altanbayar, N. Baatarjalbuu, A. Bold-Erdene, E. Sharkhuu, S. Lkhagvadorj, B. Enkhbat

*Department of Pathology and Forensic Medicine, School of Biomedicine, Mongolian National University of Medical Sciences, Ulaanbaatar, Mongolia

Background & objectives: Identifying pathogenic variants in the BRAF gene is important in various ways. Therefore, we aimed to study the V600E mutation of the BRAF gene among patients with papillary carcinomas in the Mongolian population.

Methods: A total of 46 patients with PTC collected from 2017 to 2019 at the National Cancer Center of Mongolia. DNA extractions from Formalin-Fixed Paraffin-Embedded and fresh thyroid tumour tissue were extracted using a genomic DNA kit. ABI 3730xl genetic analyser was used to identify DNA sequencing.

Results: Out of the PTC cases, 38 (82.6%), 6(13%), 1(2.2%), and 1(2.2%) cases were classic, follicular, oncolytic, and tall-cell variants, respectively. BRAFV600E alteration was found in 9(19.6%) of 46 cases that were diagnosed as classic papillary variants, histopathologically. The mutation was not relative to the patients’ age or gender (p>.005). In terms of clinicopathological features such as tumour stage, capsular and vascular invasion, histological type, lymph node metastasis, extra-thyroid invasion, and tumour location were not different between 2 groups (with or without BRAFV600E mutations)(p>.005).

Conclusion: BRAFV600E mutation was detected in 19.6% of PTC cases in our study. There was no correlation between BRAFV600E mutation and increased PTC aggressiveness in the study.

Funding: This study funded by a research grant from the Division of Science and Technology, Mongolian National University of Medical Sciences (MNUMS).

PS-11-029

Sinonasal intestinal-type adenocarcinoma showing contralateral intestinal metaplasia: a morphological and immunohistochemical study

C. Taverna*, A. Franchi

*Department of Translational Research and of New Technologies in Medicine and Surgery, University of Pisa, Italy

Background & objectives: Intestinal metaplasia (IM) can be present in the sinonasal mucosa adjacent to intestinal type adenocarcinoma (ITAC), possibly being a step in the development of these neoplasms. Herein we examined the mucosa contralateral to the tumour to identify areas of IM.

Methods: Nineteen patients (17 males, 2 females), age ranging between 44 and 89 years (mean 63.7), affected by unilateral ITAC treated with bilateral surgical approach were enrolled. The series included 3 well differentiated, 12 moderately differentiated, 1 poorly differentiated and 3 mucinous ITACs. Ethmoidal mucosa contralateral to the tumour site was morphologically and immunohistochemically analysed using cytokeratin 20 and CDX2.

Results: In 3 cases (15,7%) we observed foci of IM in the sinonasal mucosa of the opposite side of the tumour, with no evidence of dysplasia. Metaplastic areas involved both the surface and glandular epithelia.

Conclusion: A subset of sinonasal ITAC patients simultaneously shows foci of IM in the contralateral ethmoid mucosa, suggesting that IM could be associated with chronic environmental exposure and supporting the idea that the concept of “field cancerisation” could be applied to the development of ITAC in the sinonasal tract.

PS-11-030

Epidemiological and histopathological features of eyelid tumours: a 20-years retroprespective study at a tertiary university hospital in South-Western Greece

M. Papadopoulou, K. Plachouri, M. Melachrinou, V. Tzelepi*

*Department of Pathology, School of Medicine, University of Patras, Greece

Background & objectives: The aim of this study is to describe the epidemiology of primary eyelid tumours over a 20-year period, based on patient data derived from a Tertiary University Hospital in Greece.

Methods: A computerised retrieval system was used to identify all patients who underwent eyelid mass excisions with histological reports, encountered during the years 2000-2019. The demographical (age, gender), clinical and histological features along with the pathological diagnosis of each patient were documented. Descriptive statistical analyses were performed on the data. A total of 157 eyelid tumours comprised the study sample.

Results: Sixty-five (41.4%) malignant cases and 92 (58.6%) benign cases were identified. The most frequent benign diagnoses included cyst (25%), nevus (19.6%), squamous papilloma (11,96%) and seborrheic keratosis (8.7%). Malignant tumours included basal cell carcinomas (92.3%), squamous cell carcinomas (4.62%) and melanomas (3.08%). The main variants of the basal cell carcinomas were: nodular (41.7%), nodular cystic (15%), ulcerative (15%), infiltrative (13.5%) and basosquamous (6.7%). Benign eyelid lesions occurred with equal frequency in the upper and lower eyelids (43.5%). Malignant lesions were more frequently located in the lower eyelid (61.5%) compared to other areas. The mean age at diagnosis was 70 (38-86) years for malignant and 50 (4-96) for benign lesions.

Conclusion: In this Greek cohort, benign eyelid lesions affected mostly working-age individuals, and malignant lesions occurred predominantly in elderly patients. Te majority (60%) of the patients with malignant tumours were females. Males and females were equally affected by benign lesions. Among the malignant lesions, basal cell carcinoma was the most common type, with lower eyelid involvement in the majority of cases. The clinical and histological features of the tumours varied among the different variants.

PS-11-031

Features of TIMP1 expression for different types of periodontitis

V. Zakharava*, L. Kazeko, J. Benesh, E. Cherstvoy

*Belarusian State Medical University, Belarus

Background & objectives: Periodontitis is an inflammatory disease, leading to progressive destruction of the tooth-supporting apparatus and to tooth loss. The dysregulation between an activity of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMP) plays an important role in progression of inflammation.

Methods: Objective. To study features of TIMP1 expression in patients with different types of periodontitis.

A gingival biopsy was analysed from patients with aggressive (AgP, n=16), chronic simplex (CSP, n=3), chronic complex (CCP, n=23) periodontitis, and a control group (n=6). Morphometric and statistical analysis of the TIMP1 expression was performed using AperioImageScope v12.4.0.5043, Statistica10, p<0.05.

Results: The expression of TIMP1 in the biopsy was obtained in all patients with different forms of periodontitis, both in the gingival epithelium and stroma. There was a statistically significant increase of epithelial and stromal levels of TIMP1 in all groups of periodontitis compared to healthy tissue (p˂0.05). At the same time, the lowest levels of both epithelial and stromal expression were found in the CSP group, increased in the AgP (p˂0.01) and were highest in the CCP group (p=0.001). In the AgP group, compared with the CCP, there were lower levels of intensity and the proportion of strong and moderate intensity pixels (p˂0.03) of epithelial and stromal expression of TIMP1.

Conclusion: A increase in epithelial and stromal expression of TIMP1 with a dysregulation of MMPs expression in different types of periodontitis compared to the healthy tissue supports its importance in the pathogenesis of periodontal inflammation. At the same time, an even greater decrease in TIMP1 expression in the group of aggressive periodontitis compared to chronic complex periodontitis may explain the high aggressiveness of its course and can be used in the differential diagnosis of these forms at the disease manifestation stage.

Funding: "To develop and implement a diagnostic method of aggressive periodontitis, based on the determination of matrix metalloproteinases in periodontal tissues" State registration number 20180436

PS-12 | History of Pathology Posters

PS-12-001

Pathological findings of the 1918-1919 “Spanish” influenza from the autopsy reports of the Santi Giovanni e Paolo Hospital in Venice

L. Ferrari*, G. Capitanio

*Division of Pathology, Cardinal Massaja Hospital, Asti, Italy

Background & objectives: The ancient autopsies reports are kept at the Santi Giovanni e Paolo Hospital in Venice. An archive search was carried out to valuate the pathological findings of the Spanish flu from autopsy descriptions.

Methods: The cases reporting diagnosis named as “flu bronchopneumonia” have also been selected since 1918. In Venice, between 1918 and 1919, 1669 autopsies were performed, respectively 807 in 1918 and 862 in 1919. The autopsies were performed only on deceased in the hospital, not on people deceased in their own home.

Results: The first case of Spanish flu in Venice dates back to 26th September 1918. The autopsy was performed on a 46-year-old male who died at Santi Giovanni e Paolo Hospital. The last was reported on 19th January 1920, remarkably associated with Encephalitis lethargica. The cases reporting flu bronchopneumonia are 169. The reports describe a haemorrhagic bronchopneumonia, splenic reactive hyperplasia and blood congestion of kidneys and liver. These pathological findings were similar to those already described in a similar archive research performed at the Pathology Department of the University of Turin.

Conclusion: The autopsy reports of Santi Giovanni e Paolo Hospital of Venice confirm the temporal distribution of deaths following the pandemic trend of Spanish flu. The pathological findings are comparable to those described in literature, confirming the relevance of old autopsy reports as historical documentation for the history of pathology.

PS-12-002

A unique museological display of antique urologic stones

R. Henriques De Gouveia*, T. Ferreira, R. Gonçalinho, V. Almeida, M.J. Martins, V. Sousa, L. Carvalho

*INMLCF & FMUC & CHLO, Portugal

Background & objectives: 'Urologic Lithiasis' affects mankind since Antiquity. Currently, despite multiple therapeutic measures, incidence is rising with high recurrence rate, even in transplanted kidneys. Authors aim to draw attention to study the resources kept in the "Museum of Anatomical Pathology" in Coimbra.

Methods: Retrospective study of specimens kept in the Coimbra Museum was performed, searching for the different characteristics of urological calculi. Photographs were taken and comparison with literature was applied.

Results: Ninety (n=90) sets of calculi corresponding to single stones or aggregates of calculi gathered in containers or hangers, varied in their form, colour and consistency. Topography was registered: renal (n=14), bladder (n=64), urether (n=3); as well as composition: calcium (n=2), cistine (n=2), uric acid (n=3), struvite (n=2).

Conclusion: Etiopathogenic factors underlying urolithiasis are multiple, ranging from infection, dehydration, diet to metabolic syndrome and genetic background. Increased longevity and alimentary habits change, among other risk factors, favour higher incidence, both in adults/elderly and children. During lithiasic patients’ clinical workup evaluation, consensus studies have shown the importance of crystalluria and calculi morphoconstitutional analysis. This XIXth century Museum collection is available for Medical Students and Residents to review urologic calculi and correlate with patients symptoms. Other areas of Science are welcome.

PS-12-004

Clinical and morphological analysis as a tool for finding diagnostic errors: traditions laid down by N.I. Pirogov in the "Annals of the surgical department of the clinic of the Imperial Dorpat University"

M. Mnikhovich*, T. Bezuglova

*Research Institute of Human Morphology, Russia

Background & objectives: The world-famous scientist Nikolai Ivanovich Pirogov made an important contribution to the development of pathological anatomy. In 1837 N.I. Pirogov published a work: "Annals of the surgical department of the clinic of the Imperial University in Dorpat".

Methods: In "Annals" N.I. Pirogov, included a collection of case histories, arranged in sections depending on the type of diseases, summarizing articles. There were also forty-eight topics related to the pathological anatomy of surgical pathology. The Annals revealed the features of the operative technique, they became the basis for clinical and morphological analysis, which is currently a tool of pathological anatomy.

Results: N.I. Pirogov wrote: "It is my sacred duty to tell the readers frankly about my medical activity and the results of it, since every conscientious person, especially a teacher, should have a kind of inner need, perhaps, rather to publicize his mistakes in order to warn other people against them." Pirogov considered self-criticism to be a method that could improve the results of clinical practice.

According to Pirogov's Annals, doctors should analyse their professional mistakes, enriching their experience and the cumulative experience of medicine.

Pirogov compared the data of clinical examinations with the data of autopsies, in fact, it was about clinical anatomical conferences.

Conclusion: Pirogov's attitude to medical errors prompts us to deepen the meaning of this maxim in moral and ethical terms. Anyone who stops at the pessimistic and apathetic statement "medical errors are inevitable" is in the position of ethical surrender, which is immoral and unworthy of the title of a doctor.

PS-12-005

Prognosis and prediction in medicine and pathology in a historical context

S. Mozgovoi*, E. Abrosimova, A. Kononov

*Omsk State Medical University, Russia

Background & objectives: Prediction and prognosis (forecast) are two overlapping and coexisting terms in modern medicine. Notions about the prognosis of a disease primarily imply the nature of its natural course, and the term «predicate» reflects rather the probability of response to treatment.

Methods: The scientific works devoted to prognostics and predication (prediction) are analysed, starting with Hippocratic's «Prognostic» and ending with modern works dedicated to 4p and 5 p-medicine. Scientific articles, philosophical definitions, data of dictionaries were analysed according to basic definitions about prognosis as the nature of the current and the outcome of the disease and prediction as possibility of «predict» pathologies.

Results: The evolution of the predictive approach in medicine from ancient times to modern research is considered. It has been established that the prognosis existed from the very beginning in two directions: as a prediction of the outcome of a disease and as an assessment of the risk of a disease, the ability to anticipate and prevent its development. The modern prognostic approach is based on individualized conception of the person and his individual reaction to the treatment, which is especially relevant in the development target treatment of tumour diseases. It is in this context that prediction seems to be considered in modern times.

Conclusion: Prognosis in medicine is a specific historical concept that evolves together with the development of the principles and values of medical discourse: from a general understanding of human, disease and organism to maximum individualization. The relevance of the term prediction, related to the breakthrough in individualizing the treatment of tumour pathologies, characterizes one of the stages of development of prognostics approach.

PS-12-006

The pathways that defined the construction of pathology’s history in Ceara, state in the Northeast of Brazil

D. Nunes Oliveira*, L. Goiana Albuquerque, L. Silveira de Oliveira, M.C. Rocha Muniz, J.S. Pereira Filgueira, A. Vidal Alves, D. Nunes de Melo, J. Carneiro Melo

*University of Fortaleza, Brazil

Background & objectives: The History of Pathology has guiding principles shared with all other medical specialties. In Ceara, the pathways that defined it were marked by challenges and important achievements. This study seeks to review the History of Pathology in Ceara.

Methods: The present study consists of a literature review. The search for articles was conducted in the PubMed, Scielo and Lilacs databases. Literary works on the subject were also considered. The descriptors History, Pathology, Medicine and Ceará were applied, utilizing the boolean operator and. The period from 2010 to 2021 was set as the search limit.

Results: In Ceara, the evolution of medical care has been marked, for a long time, by the lack of means to prevent diseases. At first, the introduction of studies focused on Pathological Anatomy faced challenges, which included rudimentary equipment and inadequate facilities. In 1949, the first Pathological Anatomy laboratory was set up, beginning the task of providing anatomopathological diagnoses. The first systematic research in Pathological Anatomy was on visceral leishmaniasis, during an endemic period. The introduction of routine necropsy services allowed a rapid change in the quality of the services provided. In early 2021, the first autopsy using the Minimally Invasive Autopsy (MIA) technique was performed in the state.

Conclusion: It is indisputable that anatomopathological reports, obeying pathogenetic and chronological aspects, are instruments for a better understanding of the diseases. It is necessary to promote the training of pathologists with professional qualifications who, inspired by the pioneers of the past, can contribute to the development of Pathology in Ceara.

PS-12-007

Questionnaire portrait of the Russian pathologist, scientist and educator, academician of the Academy of Medical Sciences of the USSR, Professor Vladimir Georgievich Garshin (19.12.1887–20.04.1956)

A. Zubritsky*

*Russia

Background & objectives: Born in Novgorod in the family of a forensic investigator. He graduated from the Medical Faculty of the Kiev Imperial University of St.Vladimir (1913) and was awarded the degree of “doctor with honours”.

Methods: As a student, he showed interest in pathological anatomy and was left at department “to prepare for title of professor” in this subject. He was sent to Berlin to improve his knowledge, but in view of outbreak of First World War, he was arrested and placed in concentration camp, a month later, according to decision of Berne Convention, was released.

Results: In 1935, based on the totality of his works, he was awarded the academic degree of Doctor of Medical Sciences. Assistant of the Pathology Department (PD) at the Kiev Women's Medical Courses (1913); Assistant Commissioner of the Red Cross General Directorate, was wounded in fighting on the San River (1914). Head of the Growth Laboratory of the PD of the Institute of Experimental Medicine, etc. (1933–52); forced to leave work due to the progression of stroke (1952);

Conclusion: creator of fundamental research on aseptic inflammatory growths and epithelial metaplasia; he made a great contribution to the study of the pathology of starvation and the wound process, as well as hyperplastic changes, their biological potential in refraction to malignancy; man of high erudition, culture, and intelligence; he loved, knew poetry and was a close friend of the poetess Anna Akhmatova. He died at the age of 69 from cancer. He was buried at the Seraphim Memorial cemetery in St. Petersburg.

PS-12-008

Academician of the Academy of Medical Sciences of the USSR, honoured scientist of the RSFSR, Professor Mikhail Alexandrovich Skvortsov – the founder of the pathological anatomy of childhood diseases (02.10.1876–08.03.1963)

A. Zubritsky*

*Russia

Background & objectives: Born in Moscow. He graduated from the gymnasium (1894) and the Medical Faculty of Moscow University (1899). Zemsky, district and factory doctor in Kaluga province (1899–1902); Assistant of the Pathology Department (PD) at Moscow University (1902–11);

Methods: Prosector at the Morozov Children's Hospital (1911–53) and at the same time a Professor of the PD of the 1st and 2nd Moscow Medical Institute; Head of the Laboratory of Paediatric Pathological Anatomy at the Institute of Normal and Pathological Morphology (1945) and at the Institute of Pediatrics (1953).

Results: Awarded the 1st Prize of the International Anti-Rheumatic Committee for his works on rheumatism (1938); he created a unique and rich museum of macro-and micrоpreparations and a large school of children's pathologists; for the first time he developed the pathological anatomy of the superficial forms of pulmonary actinomycosis; he gave a new interpretation of allergic vascular pathology in early childhood, the significance of the inflammatory nonspecific reaction of the myocardium in rheumatism