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Year : 2009  |  Volume : 52  |  Issue : 2  |  Page : 275-277
Unusual features of medullary thyroid carcinoma in multiple endocrine neoplasia type 2A


Department of Pathology, Institute of Medical Sciences, Banaras Hindu University, Varanasi - 221 005, UP, India

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How to cite this article:
Patne SC, Kumar M, Tanwar P. Unusual features of medullary thyroid carcinoma in multiple endocrine neoplasia type 2A. Indian J Pathol Microbiol 2009;52:275-7

How to cite this URL:
Patne SC, Kumar M, Tanwar P. Unusual features of medullary thyroid carcinoma in multiple endocrine neoplasia type 2A. Indian J Pathol Microbiol [serial online] 2009 [cited 2020 Feb 24];52:275-7. Available from: http://www.ijpmonline.org/text.asp?2009/52/2/275/48946


Sir,

Medullary thyroid carcinoma (MTC) is a rare ­calcitonin-producing neuroendocrine tumor, which accounts for 5-8% of all the thyroid carcinomas. [1] MTC can be sporadic or familial. There are three familial forms of MTC-multiple endocrine neoplasia type 2 (MEN2A),-MEN2B and familial MTC. [2] We herein describe unusual features of MTC in the rare MEN2A.

A 21-year-old male patient presented with complaints of palpitation since 1 year and a neck mass of 6 months duration. Local examination of the neck showed a 3cm × 2cm-sized firm solitary thyroid nodule on the right side. Cervical lymphadenopathy was absent. Fine needle aspiration cytology (FNAC) of the nodule was suggestive of MTC [Figure 1a] and [Figure 1b]. Further investigations showed basal calcitonin 314pg/ mL (normal 5-40pg/mL), calcium 9.6mg%, phosphorus 4.0mg% and parathyroid hormone 21pg/mL. Screening ultrasound and later contrast enhanced computed tomography (CECT) scan of the abdomen revealed a well-marginated right adrenal mass measuring 4.4cm × 4.1cm. The contralateral adrenal gland was normal. The urinary vanillyl mandelic acid level was 8.6mg/24h (normal <6.5mg/24h). These radiological and biochemical findings suggested a right adrenal pheochromocytoma. Thus, a clinical diagnosis of MEN syndrome was made and the patient was referred for the surgery. His adrenal mass was excised with the prior adrenergic blockade. Two weeks later, total thyroidectomy with neck node dissection was performed. The excised adrenal specimen measured 4cm × 4cm × 3cm [Figure 1c]. Histological examination confirmed the diagnosis of pheochromocytoma [Figure 1d] and [Figure 1e]. The thyroidectomy specimen measured 5cm × 3cm × 2.5cm [Figure 1f]. Histologically, the tumor was composed of spindle-shaped cells arranged in a paragangliomatous pattern [Figure 1g]. The individual cells had moderate amount of granular eosinophilic cytoplasm, minimally pleomorphic nuclei, characteristic speckled chromatin and occasional prominent nucleoli [Figure 1h]. Lymphovascular invasion, mitotic figures and necrosis were not present. The contralateral lobe and isthumus of the thyroid gland were not involved by the tumor. Resected lymph nodes show reactive hyperplasia. Congo red for the amyloid staining was negative. Cytoplasmic immunoreactivity against calcitonin validated the diagnosis of MTC. First-degree relatives of the patient did not have any symptoms of the endocrine tumors. Overall, the final diagnosis was MEN2A. In an 11-month post-operative follow-up period, the patient was well, without any recurrence or metastatic disease.

MTC of our patient had certain remarkable features. The rare paragangliomatous variant of MTC closely mimicked paraganglioma on histology. This created diagnostic difficulty, which was further accentuated with the negative amyloid staining. However, positive immunostaining for calcitonin confirmed the diagnosis of MTC and helped us to exclude paraganglioma. Approximately 15-20% of MTC are amyloid negative while all show calcitonin immunoreactivity; therefore, calcitonin immunoreactivity is considered the gold standard for diagnosis of MTC. [3] In comparison with sporadic cases, the familial form presents with bilateral and multicentric tumors occurring at a mean age of 20 years. [2] Moreover, approximately 50% of the patients have clinically detectable cervical lymph node metastasis at presentation. [3] In contrast, MTC of our patient seems to follow an indolent course with the unifocal tumor, limited only to the single lobe and without cervical lymphadenopathy.

MEN2A is a constellation of MTC in 100%, unilateral or bilateral pheochromocytoma in 20-50% and primary hyperparathyroidism in 5-20% patients. [4] Hyperparathyroidism was absent in our patient as parathyroid hormone, calcium and phosphorus levels were normal. During a 30-year study, only two patients of MEN2A were found among 234 Indian patients with MTC. [5] The reason for this low incidence of MEN2A in India is unknown. Nevertheless, patients with MTC should be evaluated for possible pheochromocytoma. A coexisting pheochromocytoma should be removed before thyroidectomy to avoid potentially fatal hypertensive crisis during thyroid surgery. [2]


   Acknowledgement Top


Authors would like to express their sincere gratitude to Dr. R.S. Garbyal for taking excellent photomicrographs of the cytology slides.

 
   References Top

1.Dionigi G, Bianchi V, Rovera F, Boni L, Piantanida E, Tanda ML, et al . Medullary thyroid carcinoma: Surgical treatment advances. Exp Rev Anticancer Ther 2007;7:877-85.  Back to cited text no. 1    
2.Multiple endocrine neoplasia type 2A, 2B, and non-MEN familial -medullary thryoid carcinoma. Available from: http://www.endotext.org/guthormones/guthormone5/ch01s02.html.  Back to cited text no. 2    
3.Silverberg SG, DeLellis RA, Frable WJ, LiVolsi VA, Wick MR, editors. Silverberg′s principles and practice of surgical pathology and cytopathology. 4 th ed. Philadelphia PA: Churchill Livingstone Elsevier; 2006.  Back to cited text no. 3    
4.Marini F, Falchetti A, Del Monte F, Carbonell Sala S, Tognarini I, Luzi E, et al . Multiple endocrine neoplasia type 2. Orphanet J Rare Dis 2006;1:45.  Back to cited text no. 4    
5.Desai SS, Sarkar S, Borges AM. A study of histopathological features of medullary carcinoma of the thyroid: Cases from a single institute in India. Indian J Cancer 2005;42:25-9.  Back to cited text no. 5  [PUBMED]  Medknow Journal

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Correspondence Address:
Mohan Kumar
Department of Pathology, Institute of Medical Sciences, Banaras Hindu University, Varanasi - 221 005, UP
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0377-4929.48946

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  [Figure 1a], [Figure 1b], [Figure 1c], [Figure 1d], [Figure 1e], [Figure 1f], [Figure 1g], [Figure 1h]



 

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