gliomas derived from ependymocytes that tend to present as malignant intracranial tumors in children and as benign intraspinal neoplasms in adults; may arise from any level of the ventricular system or central canal of the spinal cord; intracranial ependymomas most frequently originate in the fourth ventricle and histologically are densely cellular tumors which may contain ependymal tubules and perivascular pseudorosettes; spinal ependymomas are usually benign papillary or myxopapillary tumors.