Ependymoma is a WHO grade II slow-growing tumor of children and young adults that originates from the wall of the cerebral ventricles or from the spinal canal and is composed of neoplastic ependymal cells.
These types of tumors account for 3–5% of all neuroepithelial tumors and for 30% of those in children younger than 3 years.
Imaging and Location
Ependymomas are the most common neuroepithelial neoplasms in the spinal cord and make up 50–60% of spinal gliomas. These types of tumors occur at any site in the ventricular system and in the spinal canal; they develop most commonly in the posterior fossa and in the spinal cord, followed by the lateral ventricles and the third ventricle.
Histologic variants include:
- cellular ependymoma,
- papillary ependymoma,
- clear cell ependymoma,
- tanycytic ependymoma.
MR imaging shows the heterogeneity of the tumors, which reflects areas of necrosis, bleeding, and cysts (Spoto et al. 1990). In some cases, calcifications are present; however, those are small and hardly seen on MRI. On T2 the tumors are not as high in signal intensity as other gliotic tumors due to the high cellular density. Hydrocephalus is a common finding due to the extension of the tumors in the ventricles and through the foramina.
- M.F. Reiser, W. Semmler, H. Hricak (Eds.) "Magnetic Resonance Tomography", Springer 2008