ependymoma /ipen′dimō″mə/ [Gk, ependyma, an upper garment, oma, tumor] , a neoplasm composed of differentiated cells of the ependyma. The tumor, which is usually a benign pale, firm, encapsulated, somewhat nodular mass, commonly arises from the roof of the fourth ventricle and may extend to the spinal cord. Primary lesions may also develop in the spinal cord. Also called ependymocytoma.
