Medullary thyroid carcinoma (MTC) is extremely uncommon having varied presentations & their prognosis is not exactly known; but as MTC is an aggressive tumor hence it needs to be documented in literature to help to know the behaviour of this variant. We report a rare presentation of medullary carcinoma of thyroid in a 48 years old man who presented with huge swelling at left side of neck extending from parotid to supraclavicular region with normal-sized thyroid gland of long duration. FNAC & incision HPE of this swelling was inconclusive so we had operated this swelling. Immunohistochemistry reported it as metastatic Medullary carcinoma of thyroid; tumor cells express Cytokeratin, Calcitonin, EMA, Synaptophysin, Chromogranin-A. The stroma shows deposits of Amyloid, which have been confirmed by Congo red staining. Post-operatively FNAC from thyroid gland supported the diagnosis of Medullary carcinoma. Post-operatively the residual mass was regressed with chemotherapy & radiotherapy. The calcitonin level also decreased following this treatment. There was no recurrence at 11 months but ultimately patient died with metastasis.
Keywords: Medullary thyroid carcinoma; Neck mass; Unknown primary.