ABSTRACT
Struma ovarii, which is classified as benign or malignant, is a mature ovarian teratoma consisting mainly of the thyroid tissue. Here, we present the case of malign struma ovarii in a patient with right adnexal mass. In a 53-year-old female, who was referred to our hospital with pelvic pain, abdominopelvic imaging revealed a cystic lesion measuring 15x14 cm in diameter in the right adnexa. Total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Microscopic evaluation revealed a 1.5x1x0.5 cm papillary carcinoma focus in frozen sections of the mural nodule which was observed inside the cyst. Following the surgical procedure, the patient’s TSH levels were kept low by thyroxine treatment, and it was decided to follow the patient by annual measurement of thyroglobulin levels and pelvic imaging. There is not a common consensus on optimal treatment of malignant struma ovarii. Treatment options depend on cases or case series.