Ependymomas are an uncommon group of glial tumors that typically arise within or adjacent to the ependymal lining of the ventricular system . Ependymomas occasionally occur within the brain parenchyma or outside the central nervous system (CNS).
Ependymomas account for less than 10 percent of tumors arising in the central nervous system (CNS) and 25 percent of primary tumors originating in the spinal cord.
The clinical presentation and management of ependymomas arising in the brain will be reviewed here. Ependymomas arising in the spinal cord are discussed separately. (See "Spinal cord tumors".)
Age and anatomic location — The incidence of ependymomas is approximately equal in males and females. The median age at diagnosis in children is five years of age, and 25 to 40 percent of patients are less than two years old.
The fourth ventricle is the most common infratentorial site and extension into the subarachnoid space occurs frequently, sometimes with encasement of the medulla and upper cervical cord. Supratentorial lesions can be either intraventricular, typically in the lateral ventricles, or parenchymal.