A case report of spindle cell variant of medullary thyroid carcinoma in Hashimoto’s thyroiditis

Abstract

Background: Hashimoto’s thyroiditis is a common autoimmune thyroid disease and often coexists with differentiated thyroid carcinomas, but the link between medullary thyroid carcinoma and Hashimoto’s thyroiditis is not established, so the cases of these diseases occurring simultaneously are rare in the literature. Here we report a case of spindle cell variant of the medullary thyroid carcinoma in underlying Hashimoto’s thyroiditis. Case presentation: A 65-year old female was followed up in our Center because of hypothyroidism due to thyroid autoimmune disease. On neck ultrasound, an 11 X 7 X 9 mm hypoechoic nodule in the left thyroid lobe was found, and cytology was suggestive for spindle cell variant of medullary thyroid carcinoma. Calcitonin serum level was measured, and found elevated. After total thyroidectomy, pathology was compatible with spindle cell medullary thyroid carcinoma and Hashimoto’s thyroiditis. Conclusion: Medullary thyroid carcinoma in Hashimoto’s thyroiditis is rare, but must not be taken out of consideration when thinking about routine ultrasound check-ups in patients with non-nodular autoimmune thyroid disorder.