Medullary Thyroid Carcinoma in a Patient With Hyperthyroidism:

Medullary thyroid carcinoma (MTC) is a rare thyroid malignancy of neuroectodermal origin. A coexistence of MTC with hyperthyroidism is a very uncommon association. There are 13 cases of such a coincidence reported. Our aim is to present a patient in which we diagnosed MTC coexisting with hyperthyroidism resulting from a nodular goiter. The woman, aged 40, was admitted with a toxic nodular goiter to our department in July 2002. She was diagnosed with hyperthyroidism in May 2002 and successfully treated with methimazole until clinical and biochemical remission was achieved. The patient was referred to surgery for thyroidectomy because of the suspicion of MTC in an ultrasound-guided fine needle aspiration biopsy (FNAB). Postoperative histopathology confirmed the initial FNAB-based diagnosis. This case is particularly interesting because 10 of the 13 cases in the literature had Graves disease.