Large supratentorial ectopic ependymoma with massive calcification and cyst formation--case report.

A 6-year-old boy presented with a large supratentorial ependymoma with massive calcification and central cyst formation manifesting as generalized convulsion and right hemiparesis. Computed tomography and magnetic resonance imaging showed a large, poorly enhanced, left frontal mass with massive calcification and a central cyst. Angiography revealed no extracranial blood supply to the tumor, which was supplied by branches of the left middle cerebral artery. The patient underwent total resection of the tumor, which was located in the parenchyma with no dural attachment. The tumor was clearly demarcated and dissected subpially from the surrounding brain parenchyma. The surgical findings suggested no relationship with the lateral ventricular system. Histological examination of the tumor demonstrated perivascular pseudorosette formation and mitosis with massive calcification, and immunocytochemical reactivity for glial fibrillary acidic protein and epithelial membrane antigen, but not synaptophysin. These findings were compatible with ependymoma, World Health Organization grade 2. Postoperative magnetic resonance imaging clearly showed that the tumor was located in the intradural, intraaxial space with no relationship to the ventricles.