ependymoma
Pronunciation: eh-PEN-di-moh-mah
A glial tumor arising from ependymal cells lining the ventricular system and central canal of the spinal cord.
Full Definition
An ependymoma is a neuroepithelial tumor that develops from ependymal cells, which normally line the ventricular system and the central canal of the spinal cord. These tumors are characterized by perivascular pseudorosettes and true ependymal rosettes, though the latter are less common. Ependymomas can occur throughout the central nervous system but are most frequent in the posterior fossa in children and in the spinal cord in adults. They are graded from I to III based on histological features including cellularity, mitotic activity, and the presence of necrosis or vascular proliferation.
Usage
Usage note: Grade is critical for prognosis; anaplastic ependymomas (grade III) have significantly worse outcomes.
In Context
- "The fourth ventricular mass showed characteristic perivascular pseudorosettes consistent with ependymoma." — Neuropathology report
- "Intraoperative consultation suggested ependymoma based on the perivascular arrangement of tumor cells." — Frozen section report