Malignant struma ovarii with a focus of papillary thyroid cancer: a case report.

Struma ovarii is a rare form of ovarian neoplasm and its malignant transformation is even rarer. Because of its rarity, there is no consensus about its diagnosis and management in the literature. A 53-year-old woman with left adnexial mass underwent total abdominal hysterectomy with bilateral salpingo-oopherectomy. Postoperatively, she was diagnosed with a malignant struma ovarii. Postoperative thyroid ultrasonography revealed a 0.5-cm solid nodule in the thyroid gland and total thyroidectomy was done. Pathology report was nodular hyperplasia of benign character. She is currently disease-free for 1 year but long-term follow-up with thyroglobulin levels is necessary due to reports of increasing recurrence rates.