A case of malignant struma ovarii diagnosed after laparoscopic surgery

Abstract

Malignant struma ovarii is a rare germ cell tumor of the ovary. It accounts for only 2.7％ of all ovarian teratomas and is predominantly found in women aged 40-60 years. A 56-year-old multiparous woman presented with fever. Computed tomography and magnetic resonance imaging revealed a pelvic cystic mass, and a laparoscopic bilateral salpingo-oophorectomy was performed. Histopathology of the left ovary revealed a papillary thyroid carcinoma （PTC） arising within the teratoma. Staging laparotomy involving total hysterectomy, omentectomy, pelvic lymphadenectomy, and para-aortic lymphadenectomy was performed. Postoperative histopathology confirmed the presence of PTC in mature teratoma （stage IA）. The patient did not receive any adjuvant therapies. Malignant struma ovarii cannot be diagnosed preoperatively. There are no imaging features unique to malignant struma ovarii. Even if imaging features suggest a benign solid component mass, it is important to consider the prospect of a malignant tumor.