[Cystic struma ovarii, a rare form of ovarian tumor--case report, and review of the literature].

Struma ovarii represents less than 3% of ovarian teratomas. It can be associated with thyroid biology abnormalities, and in exceptionally rare cases it can be malignant. The authors report a case of a 31-year-old woman who underwent resection of a left ovarian cyst, presenting with the clinical features of an ovarian cancer (large pelvic mass, ascites and elevated CA-125 serum levels). The pathologic diagnosis was benign struma ovarii. The postoperative thyroid function remained normal.