Ependymoma of the ovary: report of three cases.

Three apparently pure ependymomas of the ovary occurred in young women 25 to 35 years of age who presented with abdominal swelling or pain. At operation one tumor was stage IC, and two were stage III. On microscopic examination the tumors contained cells with fibrillary cytoplasmic processes, often arranged around blood vessels to form perivascular pseudorosettes. Immunohistochemical staining for glial fibrillary acidic protein confirmed the nature of the tumor in each case. The patient with the stage IC tumor was alive and well five years postoperatively. One patient with stage III disease died of tumor six years postoperatively, and insufficient time elapsed after treatment of the second to allow meaningful follow-up data. These cases illustrate the rare occurrence of ovarian tumors resembling differentiated tumors of the central nervous system. Recognition and distinction of these tumors from common epithelial tumors, which they may resemble, have important prognostic and therapeutic implications.