Ependymomas

Ependymomas are rare tumors of neuroectodermal origin and the third most common pediatric brain tumor following astrocytoma and medulloblastoma. They arise from radial glial-like stem cells in the cerebral subven-tricular zone (SVZ), lining the fourth ventricle, and within the spinal cord. The typical location of these tumors is different in adults and children. Most childhood ependymomas are intracranial, while in adults they more commonly occur in the spinal cord. They locate infratentorially in 65% of pediatric cases, most often arising from the floor of the fourth ventricle. The remaining 35% of ependymo-mas in children occur equally divided between the spinal cord and supratentorial intracranial space.