Ependymoma arises from ependymal cells lining the cerebral ventricles and the central canal of the spinal cord. It usually occurs in the floor of the 4th ventricle (25% of tumors in the 4th ventricle region), rarely in the mediastinum, lung or ovaries.
Pathology: non-anaplastic (low-grade) - papillary - mixopapillary (in filum terminale) - subependymoma; anaplastic.
Symptoms: headache (80%); nausea and vomiting (75%); ataxia or vertigo (60%). Ependymomas have the potential to spread through the cerebrospinal fluid (CSF) (seeding process).
MR findings: T1WI - heterogeneous, usually iso- to hypointense, cystic foci slightly hyperintense to CSF; T2WI - hyperintense cystic foci; T1 + contrast - mild to moderate, heterogeneous enhancement.
Differential diagnosis: medulloblastoma; cerebellar pilocytic astrocytoma; brainstem glioma; atypical teratoid-rhabdoid tumor; dermoid-epidermoid; choroid plexus papilloma; oligodendroglioma; glioblastoma multiforme; pleomorphic xanthoastrocytoma.
Treatment: surgical resection +/- chemotherapy, radiation therapy (Ependymomas rank 2nd only to medulloblastomas in radiosensivity). Lesions in the 4th ventricle region are approached via midline suboccipital craniectomy.
Pathology: non-anaplastic (low-grade) - papillary - mixopapillary (in filum terminale) - subependymoma; anaplastic.
Symptoms: headache (80%); nausea and vomiting (75%); ataxia or vertigo (60%). Ependymomas have the potential to spread through the cerebrospinal fluid (CSF) (seeding process).
MR findings: T1WI - heterogeneous, usually iso- to hypointense, cystic foci slightly hyperintense to CSF; T2WI - hyperintense cystic foci; T1 + contrast - mild to moderate, heterogeneous enhancement.
Differential diagnosis: medulloblastoma; cerebellar pilocytic astrocytoma; brainstem glioma; atypical teratoid-rhabdoid tumor; dermoid-epidermoid; choroid plexus papilloma; oligodendroglioma; glioblastoma multiforme; pleomorphic xanthoastrocytoma.
Treatment: surgical resection +/- chemotherapy, radiation therapy (Ependymomas rank 2nd only to medulloblastomas in radiosensivity). Lesions in the 4th ventricle region are approached via midline suboccipital craniectomy.
References
- Handbook of Neurosurgery - sixth edition - Mark S. Greenberg - ed. Thieme.
- Ross JS, Brant-Zawadzki M, Moore KR, et al.. Diagnostic Imaging Spine. First edition - Amirsys - Elsevier Saunders - 2004.
