Ependymoma-like tumor of the mesovarium.

We report a case of primary extramedullary ependymoma, arising from the mesovarium in a 47-year-old woman and discovered incidentally during routine hysterectomy for uterine leiomyomas. The tumor exhibited the light microscopic, immunohistochemical, and ultrastructural features of a typical ependymoma, including a prominent pseudorosette pattern, positive staining for glial fibrillary acidic protein, and electron microscopic visualization of microvilli, intermediate filaments, basement membranes, and long cytoplasmic processes. While the occurrence of subcutaneous ependymomas in the sacrococcygeal region and metastatic central nervous system tumors at various sites are familiar, we believe this case to be a rare example of a primary ependymoma arising in a different and unusual extramedullary location.