Co-Existence of Medullary and Papillary Carcinomas of Thyroid - Case Report and Brief Review of Literature

Abstract

BACKGROUND Co-existence of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) in the same thyroid is an extremely rare phenomenon. A few cases of such co-existence have been repored in literature. We report a case of 44-year-old lady who was detected to have thyroid swelling by her clinician, which on ultrasound was suggestive of multinodular goitre. Her thyroid function tests were normal. Fine needle aspiration cytology was suggestive of medullary carcinoma of thyroid. She underwent total thyroidectomy. Microscopically there were MTC foci on the right lobe with an adjacent foci of papillary carcinoma, both of which are separated by normal thyroid parenchyma. Left lobe also showed foci of PTC. Calcitonin, synaptophysin and chromogranin were positive in the MTC foci and thyroglobulin was positive in the PTC foci, confirming the diagnosis of coexistent MTC and PTC. Coexistent MTC and PTC is a rare clinical entity and should be considered in the differential diagnosis of thyroid tumours.