Meningioma in mature cystic teratoma of the ovary.

A case of meningioma arising in a mature cystic teratoma of the ovary in a 60-year-old woman is described. The tumor was located in the right ovary, and salpingo-oophorectomy was performed. The right ovary was 10 x 10 x 8 cm in size and contained an unilocular cyst. In the wall, a solid nodule measuring 3 x 3 x 2 cm was noted. Histologically, the cyst wall was composed of typical mature cystic teratoma. In contrast, the mural nodule was composed of the proliferating spindle- and polygonal-shaped cells showing positive staining for epithelial membrane antigen and microcystic change was prominent. These findings were consistent with microcystic meningioma. The arachnoidal cells around mature brain tissue may be the origin of this unusual tumor. To the best of our knowledge, this is the first case of mature cystic teratoma with meningioma of the ovary reported in English medical literature. This case may further indicate the totipotential nature of mature cystic teratoma.