Recurrent Sinonasal CD34-Negative Malignant Solitary Fibrous Tumor Diagnosed on STAT6 Immunohistochemistry and NAB2-STAT6 Fusion

  • Aanchal Kakkar
  • Pirabu Sakthivel
  • Madhu Rajeshwari
  • Arvind Kairo
  • Mehar C. Sharma
Case Report


A spectrum of mesenchymal neoplasms occur in the sinonasal region. One of these is solitary fibrous tumor (SFT), a translocation-associated neoplasm characterized by NAB2-STAT6 gene fusion. Sinonasal SFTs characteristically display CD34 immunopositivity, which aids in diagnosis. However, a small proportion of SFTs may be negative for CD34, making diagnosis difficult. The availability of STAT6 immunohistochemistry (IHC) has helped to overcome this. Malignant SFTs, characterized by increased cellularity and mitoses > 4 per ten high power fields, are extremely unusual in the sinonasal region, with only ten such cases reported to date. We report a case of a CD34-negative malignant SFT that was diagnosed using STAT6 IHC and confirmed by demonstrating NAB2 ex 4-STAT6 ex 2 fusion, and recurred 8 months after complete excision, to highlight the aggressive nature of this tumor.


Spindle cell tumor Nose Hemangiopericytoma Solitary fibrous tumor STAT6 



The authors are grateful to the Division of Molecular Pathology, Department of Pathology, Tata Memorial Centre, Mumbai, India for performing molecular testing for NAB2-STAT6 fusion.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical Approval

This article is a case report and does not contain any studies with human participants or animals performed by any of the authors.

Informed Consent

Informed consent was obtained from the patient included in the study.


  1. 1.
    Vogels RJ, Vlenterie M, Versleijen-Jonkers YM, Ruijter E, Bekers EM, Verdijk MA, Link MM, Bonenkamp JJ, van der Graaf WT, Slootweg PJ, Suurmeijer AJ, Groenen PJ, Flucke U. Solitary fibrous tumor—clinicopathologic, immunohistochemical and molecular analysis of 28 cases. Diagn Pathol. 2014;9:224.CrossRefGoogle Scholar
  2. 2.
    Agaimy A, Barthelmeß S, Geddert H, Boltze C, Moskalev EA, Koch M, Wiemann S, Hartmann A, Haller F. Phenotypical and molecular distinctness of sinonasal haemangiopericytoma compared to solitary fibrous tumour of the sinonasal tract. Histopathology. 2014;65:667–73.CrossRefGoogle Scholar
  3. 3.
    Flucke U, Thompson LDR, Wenig BM. Solitary Fibrous Tumour. In: El-Naggar AK, Chan JKC, Grandis JR, Takata T, Slootweg PJ, editors. WHO classification of head and neck tumors. Lyon: IARC; 2017. pp45.Google Scholar
  4. 4.
    Thompson LDR, Lau SK. Sinonasal tract solitary fibrous tumor: a clinicopathologic study of six cases with a comprehensive review of the literature. Head Neck Pathol. 2017;12:471–480Google Scholar
  5. 5.
    Ganly I, Patel SG, Stambuk HE, Coleman M, Ghossein R, Carlson D, Edgar M, Shah JP. Solitary fibrous tumors of the head and neck: a clinicopathologic and radiologic review. Arch Otolaryngol Head Neck Surg. 2006;132:517–25.CrossRefGoogle Scholar
  6. 6.
    Zeitler DM, Kanowitz SJ, Har-El G. Malignant solitary fibrous tumor of the nasal cavity. Skull Base. 2007;17:239–46.CrossRefGoogle Scholar
  7. 7.
    Papadakis I, Koudounarakis E, Haniotis V, Karatzanis A. Veleg- rakis G. Atypical solitary fibrous tumor of the nose and maxillary sinus. Head Neck. 2013;35:E77–9.CrossRefGoogle Scholar
  8. 8.
    Subramaniam MM, Lim XY, Venkateswaran K, Shuen CS, Soong R, Petersson F. Dedifferentiated solitary fibrous tumour of the nasal cavity: the first case reported with molecular characterization of a TP53 mutation. Histopathology. 2011;59:1269–74.CrossRefGoogle Scholar
  9. 9.
    Xue Y, Chai G, Xiao F, Wang N, Mu Y, Wang Y, et al. Post- operative radiotherapy for the treatment of malignant solitary fibrous tumor of the nasal and paranasal area. Jpn J Clin Oncol. 2014;44:926–31.CrossRefGoogle Scholar
  10. 10.
    Roy S, Mallick S, Kakkar A, Jana M, Julka PK. Recurrent malig- nant sino-nasal solitary fibrous tumor: eliminate the enemy at the first instance. J Cancer Res Ther. 2015;11:650.CrossRefGoogle Scholar
  11. 11.
    Kao YC, Lin PC, Yen SL, Huang SC, Tsai JW, Li CF, et al. Clin- icopathological and genetic heterogeneity of the head and neck solitary fibrous tumours: a comparative histological, immuno- histochemical and molecular study of 36 cases. Histopathology. 2016;68:492–501.CrossRefGoogle Scholar
  12. 12.
    Han Y, Zhang Q, Yu X, Han X, Wang H, Xu Y, et al. Immunohistochemical detection of STAT6, CD34, CD99 and BCL-2 for diagnosing solitary fibrous tumors/hemangiopericytomas. Int J Clin Exp Pathol. 2015;8:13166–75.Google Scholar
  13. 13.
    Rekhi B, Shetty O, Tripathi P, Bapat P, Ramadwar M, Bajpai J, et al. Molecular characterization of a series of solitary fibrous tumors, including immunohistochemical expression of STAT6 and NAB2-STAT6 fusion transcripts, using Reverse Transcriptase(RT)-Polymerase chain reaction(PCR) technique: an Indian experience. Pathol Res Pract. 2017;213:1404–11.CrossRefGoogle Scholar
  14. 14.
    Janjua A, Sklar M, Macmillan C, Vescan A, Witterick IJ. Endoscopic resection of solitary fibrous tumors of the nose and paranasal sinuses. Skull Base. 2011;21:129–34.CrossRefGoogle Scholar
  15. 15.
    Fletcher CDM, Bridge JA, Lee JC. Extrapleural solitary fibrous tumor. In: Fletcher CDM, Bridge JA, Hogendoom PCW, Mertens F, editors. WHO Classification of Tumors of Soft Tissue and Bone. Lyon: IARC; 2013. pp. 80–2.Google Scholar
  16. 16.
    Kakkar A, Rajeshwari M, Sakthivel P, Sharma MC, Sharma SC. Biphenotypic sinonasal sarcoma: a series of six cases with evaluation of role of beta-catenin immunohistochemistry in differential diagnosis. Ann Diagn Pathol. 2018;33:6–10.CrossRefGoogle Scholar
  17. 17.
    Geramizadeh B, Marzban M, Churg A. Role of immunohistochemistry in the diagnosis of solitary fibrous tumor, a review. Iran J Pathol. 2016;11:195–203.Google Scholar

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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of PathologyAll India Institute of Medical SciencesNew DelhiIndia
  2. 2.Department of Otolaryngology and Head and Neck SurgeryAll India Institute of Medical SciencesNew DelhiIndia

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