Follicular variant papillary thyroid carcinoma arising within an ovarian teratoma.

A49-year-old female presented to the hospital with abdominal pain and emesis. A computed tomography (CT) scan revealed a small-bowel obstruction and a right ovarian mass measuring 4.6 cm. Following oophorectomy, histopathology revealed a mature cystic teratoma with multiple foci of benign thyroid tissue, as well as a 0.9 cm focus of follicular variant papillary thyroid cancer (Figs. 1 and 2) surrounded by normal ovarian tissue (Fig. 3). Thyroid ultrasound and serum thyroid function tests were normal. A I diagnostic whole body scan (WBS) did not reveal any abnormal uptake in the abdomen or pelvis, and an abdominal CT was normal. A high-dose (423 ı̀ Ci) I WBS performed 6 months later was also negative. Based on the small size of the primary carcinoma and the lack of evidence of metastases on imaging, the patient received no further treatment. Differentiated thyroid cancer (DTC) arising from ovarian teratomas is a rare occurrence, with an estimated incidence