Supratentorial ectopic cortical ependymoma occurring with intratumoral hemorrhage.

We report here a rare case of supratentorial ectopic cortical ependymoma. This tumor was localized in the left angular gyrus, occurred with intratumoral hemorrhage, was attached to the dura mater, exhibited no continuity with the ventricular system, showed distinctive pathological features (perivascular pseudo-rosette formations and firework-like giant rosette formations), and finally transformed to a glioblastoma-like high-grade lesion. A cortical ependymoma should be considered in the differential diagnosis of supratentorial cortical tumors with intraparenchymal hemorrhage and high vascularity, even if not in contact with the ventricular system. Although malignant transformation is unusual in cortical ependymoma, close observation and adjunctive radiotherapy are strongly recommended after the excision.