Malignant transformation in mature cystic teratoma of the ovary: three cases mimicking primary ovarian epithelial tumors.

This study reports 3 unusual cases of malignant transformation in mature cystic teratoma of the ovary (dermoid cyst), namely carcinosarcoma, atypical choroid plexus papilloma, and papillary thyroid carcinoma, the last case involving both ovaries and with peritoneal dissemination. Adequate sampling is essential in such ovarian tumors to establish their teratomatous origin and avoid an erroneous diagnosis of primary ovarian or metastatic tumors. The authors present the clinicopathological findings in these 3 cases with a review of literature.