IP Archives of Cytology and Histopathology Research 2021;6(1):49–52 Content available at: https://www.ipinnovative.com/open-access-journals IP Archives of Cytology and Histopathology Research Journal homepage: https://www.achr.co.in/ Case Report Medullary thyroid carcinoma a relatively uncommon entity: A case report Lalit Kumar 1 , Nupur Kaushik 1 , Harendra Kumar 1, *, Dharmendra Kumar 2 1 Dept. of Pathology, S.N. Medical College, Agra, Uttar pradesh, India 2 Dept. of ENT, S.N. Medical College, Agra, Uttar Pradesh, India ARTICLE INFO Article history: Received 26-02-2021 Accepted 12-03-2021 Available online 03-04-2021 Keywords: Amyloid Medullary carcinoma Procalcitonin Synaptophysin ABSTRACT Introduction: Medullary thyroid carcinoma is an uncommon primary thyroid tumour (5-10% of all thyroid malignancies) arising from parafollicular cells or C-cells. Most tumours are sporadic (75-80%) and familial syndrome multiple endocrine neoplasia; MEN-2A, MEN-2B and familial MTC in 20 to 25% cases. Case Report: We report a case of primary medullary thyroid carcinoma in a 30 years old male patient presented with complaint of midline neck swelling. On fine needle aspiration cytology diagnosis of medullary carcinoma was suggested with a differential of SETTLE (spindle epithelial tumor with thymus like differentiation). The swelling was excised and send for histopathological examination which revealed polygonal to plump spindle shaped tumor cells, arranged in lobules separated by fibrous septa, having abundant eosinophilic granular cytoplasm with round to oval nuclei, finely stippled nuclear chromatin and indistinct nucleoli and diagnosed as primary medullary thyroid carcinoma, confirmed on immunohistochemistry. Conclusion: MTC is the first human malignancy known to be associated with tumour marker and hormone calcitonin. Immunohistochemistry has definite role in confirmation of diagnosis. © This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 1. Introduction Medullary thyroid carcinoma (MTC) is a relatively rare entity, firstly described by Hazard in 1959, arising from parafollicular or C-cell, accounting for nearly 3% to 12% of all thyroid malignancy. 1,2 It can infiltrate surrounding thyroid structures and metastasize to regional lymph nodes like cervical, mediastinal and to distant organs, like lung, liver, and skeletal muscle as compared to other thyroid malignancy. In all type of MTC the average survival varied from 61% to 75% for 10 years. 3 The majority of MTCs are sporadic, while heritable incidence includes 25% to 30% of cases, which is associated with multiple endocrine neoplasia (MEN) 2A, MEN 2B, or with the familial medullary thyroid carcinoma syndrome. 1,4 Genetic forms of MTC often present as multifocal disease is caused by autosomal dominant mutations of the RET proto-oncogene * Corresponding author. E-mail address: dr_haren@yahoo.co.in (H. Kumar). with incomplete penetrance with few cases being reported to have new spontaneous mutations of the gene. As serum calcitonin is a sensitive and specific marker for MTC, routine screening of serum calcitonin levels and RET proto- oncogenes mutation should be done in the affected patient and the family members, so that the inherited forms of MTC can be detected at an early stage. 5 Histologically, MTC has no follicle development as the tumor derives from parafollicular C cells and characterized by nests of round, ovoid, polygonal, or plasmacytoid cell. Unusual histological variants of MTC have been described like spindle cell, giant cell, clear cell, melanotic, squamous and angiosarcoma-like variants, however a rarer variant showing a paraganglioma (PG)-like pattern was recognized. 6 2. Case Report A 30 year old male visited to outpatient department with chief complaint of midline neck swelling. On local physical https://doi.org/10.18231/j.achr.2021.012 2581-5725/© 2021 Innovative Publication, All rights reserved. 49