Struma ovarii accompanied by mature cystic teratoma of the other ovary: A case report and literature review.

Struma ovarii, as a monodermal variant of ovarian teratoma, constitutes <3% of ovarian teratomas. It is difficult determine a diagnosis prior to surgery. The current study reports an unusual case of struma ovarii occurring in a 49 year-old female, which was accompanied by mature cystic teratoma involving the other ovary. The final pathological diagnosis was confirmed as struma ovarii based on the typical morphology of the thyroid follicles and the results of immunohistochemical staining. The bilateral tumors were resected and follow-up examinations were planned at four month intervals. At the time of writing, the patient was well and no tumor recurrence had been identified.