The Common Vein Copyright 2010
Definition
A subependymoma is a tumor which is thought to arise from the subependymal glial layer surrounding the cerebral ventricles. They more commonly present in older males in their fifth to sixth decades of life. These intraventricular masses are generally under 2 cm in diameter with benign histologic characteristics and most often arise within the fourth and lateral ventricles
Pathologically these lesions appear as a dense fibrillary matrix with internal cysts and clustered nuclei which have the appearance of subependymal glia. Mitotic activity is generally low or absent, correlating with their relatively benign nature.
Subependymomas are generally asymptomatic and incidentally found. When large enough, however, they may present with symptoms of hydrocephalus or focal neurologic deficits.
Imaging of subependymomas includes CT, but MRI is preferred. At CT, they appear as a well- circumscribed isodense mass. Approximately one third of these lesions will demonstrate areas of calcification. When a component of hemorrhage is present, there can be areas of increased density. On MRI, they are generally isointense to gray matter on T1 and heterogeneously hyperintense on T2. In general, subependymomas do not enhance however they have been reported to demonstrate anywhere from minimal to nodular or diffuse enhancement
Ideal treatment is total surgical resection.
From the Archives of the AFIP Cerebral Intraventricular Neoplasms: Radiologic-Pathologic Correlation1Kelly K. Koeller,November 2002 RadioGraphics, 22, 1473-1505.