We present the case of a 30-year-old woman who was referred to our institut
ion with an erroneous diagnosis of poorly differentiated carcinoma of the o
vary. The patient presented pelvic pain for one year prior to surgery. A se
cond laparotomy revealed a bilateral pure ovarian ependymoma that infiltrat
ed the uterus and presented implants on the omentum. Differential diagnosis
included mainly endometrioid and small cell carcinoma of the ovary. Presen
ce of typical ependymal rosettes and positivity to GFAP confirmed the diagn
osis of ependymoma. Other teratomatous elements were not observed. Ovarian
ependymomas are rare tumors; only eight cases, to our knowledge, have been
reported in the literature. They have a favorable prognosis; patients with
advanced stage disease are reported alive and well after treatment with sur
gery and chemotherapy.