Pre-sternal thyroid swellings: a case of rare aberrant site recurrence and review of literature
Thyroid swellings enlarge caudally into the mediastinum behind the sternum. Pre-sternal swelling of thyroid origin is very rare. We present our case of pre-sternal thyroid swelling which was albeit a surprisingly rare site of papillary thyroid carcinoma recurrence and review of pre-sternal thyroid swellings reported till date.
A 60 year old female presented with a painless, progressive swelling on the anterior part of the chest for the past 2 years. A 15 cm × 8 cm vertically aligned, non tender, well defined swelling was present on the pre-sternal region, with consistency ranging from soft to firm. The swelling was fixed to the underlying tissues and a fixed level IV lymph node was palpable on the right side. Ultrasonography revealed a large mass of 15 × 7 cm with multiple cystic areas. Fine needle aspiration cytology was inconclusive twice. Patient had undergone a total thyroidectomy for papillary carcinoma 10 years back. Computed tomography findings revealed a large 15 × 6.6 × 7 cm lobulated, pre-sternal, soft tissue lesion with solid & cystic components. The mass was infiltrating the right sided strap muscles and sternocleidomastoid. FNAC was inconclusive and thyroid scan could not pick up any activity in the mass. Henceforth a PET scan was done that showed increased FDG uptake by the lesion and the level IV lymph node. The patient underwent wide excision of the mass with right functional neck dissection, along with removal with both sternal head of sternocleido-mastoid, the strap muscles and the surrounding fascia. Histopathology confirmed papillary thyroid carcinoma. Patient received post-operative radioactive iodine ablation and is healthy with no recurrence up to 30 months of follow up.
The mechanisms for pre-sternal thyroid swelling are not understood due to paucity of cases. The mechanisms proposed are invasion of strap muscles and cervical linea alba and tumor cells spread anterior to sternum, truly ectopic thyroid tissue, de novo carcinogenesis in the embryonal remnants like the thyro-thymic residues, sequestered thyroid tissue which grows later or migration of thyroid cells, incomplete clearance at the time of primary surgery or intraoperative seeding.
Pre-sternal region masses of thyroid origin are very rare. A proper work up, suspicion for thyroid mass and array of tests will be required to come to a provisional diagnosis. Since the masses reported in literature were primarily malignant, any such mass may be treated on lines of malignancy with radical surgery.
KeywordsPre-sternal Metastasis Recurrence Papillary thyroid carcinoma (PTC) Retrosternal Substernal
Fine needle aspiration cytology
Magnetic resonance imaging
Positron emission tomography
Papillary thyroid carcinoma
Almost all the goiters that enlarge inferiorly go into anterior-superior mediastinum due to the attachment of pretracheal fascia to the superior aspect of the sternum. Due to variation in the definition of substernal goiter, the incidence has wide range from 2.6–21% of patients undergoing thyroidectomy [1, 2]. The most commonly used definition states substernal goitre as a thyroid mass that has 50% or more of its volume located below the thoracic inlet. Substernal goiters represent up to 7% of mediastinal tumors . Substernal goiter are always behind the sternum, extension in front of the sternum is very rare with limited 8 cases reported in indexed literature till date. Papillary thyroid carcinoma (PTC) is the most common form of well-differentiated thyroid cancer with a favorable prognosis. Recurrence rates of papillary thyroid carcinoma are in the range of 14–30%, predominantly in the cervical region and distant metastasis is known mainly to lungs and bones . No case of pre-sternal recurrence of papillary thyroid carcinoma has ever been reported to the best of our knowledge in indexed literature. We present our unique case of 60 year old female with pre-sternal recurrence ten years after thyroidectomy.
Papillary thyroid carcinoma is the most common endocrine and thyroid cancer which accounts for 85% of all thyroid malignancies. Its incidence has been increasing worldwide as indicated by Surveillance, Epidemiology, and End Results (SEER) database from 1975 to 1992 when it increased from 4.8 to 5.8 per 100,000; however from 1992 to 2016, the incidence of papillary cancer has increased significantly from 5.8 to 14.1 per 100,000 .
Despite its well-differentiated characteristics, papillary carcinoma may be overtly or minimally invasive. In fact, these tumors may spread easily to other organs. Papillary carcinoma appears as an irregular solid or cystic mass or nodule in a normal thyroid parenchyma. Papillary tumors have a propensity to invade lymphatics but are less likely to invade blood vessels. These tumors are indolent and have a good prognosis, but frequently metastasize to regional lymph nodes in 5.4 to 13% of patients after initial surgery . Recurrence rate after primary treatment is 1.8% annually for the first 10 years.
The 10-year, 20-year and 30-year recurrence rates were 11.3, 21.8 and 29.4%, respectively. The risk of recurrence of the disease is the greatest in the first 5 years (36.9%) after the initial treatment whereas 54.8% happened within the first 10 years . Though the recurrence can occur any time, but maximum reported time was 43 years following total thyroidectomy and radioactive iodine ablation .
Local sites of recurrence include the cervical lymph nodes and the remaining thyroid tissue. Distant metastasis usually happens to bones and lungs, but less common sites include brain, adrenal, skeletal muscle . Other rare sites have been liver, skin, parapharyngeal space and right atrium . Risk factors implicated for loco regional recurrence are age, histological grade, distant metastases, extracapsular tumor extension, tumor size, and stage of disease .
Lymph node metastases are a debatable prognostic factor, having relevance in recurrence of disease, but have no relevance in survival rate of patients . Recurrence increases with the number of metastatic nodes and the degree of metastasis, as well as with extracapsular infiltration and age . This study also demonstrates that the presence of lymphatic permeation in the primary tumor correlates to an 84.4% probability of lymphatic metastasis. As with primary tumor size was of 3.8 cm versus 1.98 cm, only lymphatic permeation was correlated to an increase in metastasis in lymph nodes 65.4% versus 25% (p < 0.001). The metastatic frequency for cervical lymph node regions was IIa 18.5% versus 1.5%, III 24.3% versus 9.9%, IV 17.4% versus 18.1%, and VI 25.9% versus 71,2% .
The prognosis for PTC is better than for other types of thyroid cancer; however, the involvement of lymph nodes (LNs) is up to 15–30% at diagnosis . The 5 year survival rate for local disease is near 100%, regional disease is near 100% and distant disease is 78% . It is generally accepted that the spread pattern of LN in PTC is central compartment, ipsilateral compartment, and contralateral compartment sequentially. The factors that associated with contralateral LN metastasis were male gender, more than 2 cm size of main tumor, multifocality, bilaterality, and extra thyroidal extension.
Retrosternal goiter was first described by Haller in 1749 . Substernal goiters are largely considered to result from the descent of a cervical goiter with the primary blood supply remaining in the neck, primarily from the inferior thyroid artery. Thereafter. thyroid gland enlarges into the retrosternal area owing its position beneath the pre-tracheal fascia and the strap muscles, all of which are attached to the top of manubrium.
Several factors favor the passage of the goiter into the mediastinum: Downward traction caused by normal swallowing, respiration creating negative intrathoracic pressure, and the pull of gravity on the goiter . Some theories postulate that small cervical thyroid nodules descend beneath the pre-tracheal fascia, possibly aided by the negative intrathoracic pressures that normally occur during respiration and swallowing. As the nodule gradually enlarges, it eventually becomes trapped below the thoracic inlet, where it continues to enlarge within the confines of the thoracic cavity, commonly hidden from view and causes compressive effects as it enlarges. Malignancy can occur in 5–26.9% of substernal goiters .
By extensive search of literature we found only 8 reported cases (Table 1). These cases were essentially pre-sternal extension of the primary mass (multinodular goiter in one and papillary cancer in four) with heterotopic thyroid tissue in one and recurrence of colloid goiter in one. Details were not available for one case. Despite many cases of recurrence at unusual sites, no recurrence presenting as a pre-sternal mass has been reported. Pre-sternal thyroid swelling thus remains exceptionally rare presentation.
Details of pre-sternal thyroid swellings reported till date
Nature of mass
Belger S .
Details not available
Raman A et al. 
15 × 30 cm
Lobular cystic swelling on the anterior aspect of the neck from submental region to the xiphisternum in the pre-sternal plane
Papillary carcinoma thyroid with metastasis in regional lymph nodes
Brilli L et al. 
10 cm in length
Elongated neck mass, descending subcutaneously up to the mid region of the sternum.
Chow TL et al. 
3.5 × 3 cm
dumb-bell–shaped mass, lower part in pre-sternal plane
Papillary carcinoma thyroid
Fanantenana HN et al. 
18 × 14 cm
Firm, smooth surface mass
* H/o excision 7 years ago.
Heterotopic thyroid goitre with no evidence of malignancy.
Patil et al. 
25 × 15 cm
Mass arising from neck with multiple cysts in front of sternum
Papillary carcinoma thyroid
Tang et al. 
17 × 13 cm
Multiple cystic lesions in the chest beneath skin interlinked with the right thyroid lobe
Papillary thyroid microcarcinoma
Stumpf et al. 
20 × 9 cm
Large, firm, regular mass in pre-sternal region
* H/o partial thyroidectomy 13 years ago.
Bains L et al
15 × 8 cm
Papillary carcinoma thyroid recurrence
invasion of strap muscles and cervical linea alba and tumor cells spread anterior to sternum 
truly ectopic thyroid tissue 
De novo carcinogenesis in the embryonal remnants like the thyro-thymic residues
sequestered thyroid tissue which grows later or migration of thyroid cells 
incomplete clearance at the time of primary surgery or intraoperative seeding 
Pre sternal region masses of thyroid origin are exceptionally rare. A proper work up, suspicion for thyroid mass and array of tests will be required to come to a provisional diagnosis. Since the masses reported in literature were primarily malignant, any such mass may be treated on lines of malignancy with radical surgery.
LB, SB, RK conceptualized the manuscript, reviewed the literature, analyzed data, and made major contribution to the writing of the manuscript. LB, SB, RK, SKJ, CBS, performed the clinical examination, surgical treatment, and clinical follow-up. SM provided the histopathological diagnosis. LB, SB, RK, SKJ, CBS, DK performed final review and editing of the of the manuscript. All authors have read and approved the final version of the manuscript.
Ethics approval and consent to participate
Written consent for the publication of this case report was obtained from the patient. Approval for case report by the institutional ethics committee is not required.
Consent for publication
Written informed consent for the publication of this case report and for the accompanying images was obtained from the patient. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
The authors declare that they have no competing interests.
- 5.https://seer.cancer.gov/statfacts/html/thyro.html Accessed on 18.04.2019.
- 8.Amoako-Tuffour Y, Graham ME, Bullock M, Rigby MH, Trites J, Taylor SM, Hart RD. Papillary thyroid cancer recurrence 43 years following Total thyroidectomy and radioactive iodine ablation: a case report. Thyroid Res. 2017;10:8. https://doi.org/10.1186/s13044-017-0043-4 eCollection 2017.CrossRefPubMedPubMedCentralGoogle Scholar
- 13.Randolph GW, Duh QY, Heller KS, LiVolsi VA, Mandel SJ, Steward DL, Tufano RP, Tuttle RM, American Thyroid Association Surgical Affairs Committee’s Taskforce on Thyroid Cancer Nodal Surgery. The prognostic significance of nodal metastases from papillary thyroid carcinoma can be stratified based on the size and number of metastatic lymph nodes, as well as the presence of extranodal extension. Thyroid. 2012;22(11):1144–52. https://doi.org/10.1089/thy.2012.0043 Epub 2012 Oct 19.CrossRefPubMedGoogle Scholar
- 16.https://www.cancer.org/cancer/thyroid-cancer/detection-diagnosis-staging/survival-rates.html Accessed on 18.04.2019.
- 17.Haller A. Disputationes Anatomicae Selectae, Gottingen. Holland: Vandenhoeck; 1749. p. 96.Google Scholar
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