Sebaceous adenoma arising in mature cystic teratoma of the ovary. Case report.

We report the case of a 44-year-old female with sebaceous adenoma arising in mature cystic teratoma of the ovary. The patient had a tumor in the left ovary; 125 x 90 x 70 mm. Microscopically, the tumor consisted of structures typical of dermoid cysts. However, large areas of sebaceous proliferation were found. These areas were comprised of sebaceous nodules with features similar to a sebaceous adenoma of the skin. Immunohistochemically, the tumor showed "wild-type" expression of p53 and low proliferative activity (Ki-67 index < 5%). To verify the possibility of Muir-Torre syndrome we performed immunohistochemical examination of DNA mismatch repair proteins expression. However, all four proteins examined (MSH2, MSH6, MLH1, PMS2) were positive. Sebaceous adenoma arising in mature teratoma of the ovary is rare. To the best of our knowledge, only six cases have been reported in the literature to date.