Ependymoma Arising from the Pelvis: A Case Report

ABSTRACT

We report here on a case of an ependymoma arising from the pelvis in a 25-year-old woman. She had no evidence of abnormality in her brain and bilateral ovaries. The diagnosis was based on light microscopic, immunohistochemical, and ultrastructural features of a typical ependymoma, including the patterns of pseudorosette or true ependymal rosette, the strong immunopositivity for glial fibrillary acid protein and intermediate filaments, and cilia of tumor cells. The mass was over 20 cm in maximum diameter, and it was located between the uterus and rectum without any connection to bilateral ovaries. There were many metastatic nodules in the pelvis and omentum. In addition, the proliferation index in the most active area was 10% by immunohistochemistry using monoclonal antibody MIB-1. Although the prognosis of the pelvic ependymoma is known to be difficult to evaluate, this case may serve to illustrate the poor prognostic course, according to the size of the tumor, the evidence of metastasis, and the MIB-1 labelling index.