NCIt definition : A slow growing, WHO grade I glioma which generally occurs in young adults. It arises
almost exclusively in the conus medullaris, cauda equina, and filum terminale of the
spinal cord. It generally has a favorable prognosis and is characterized histologically
by tumor cells arranged in a papillary manner around vascularized mucoid stromal cores.
(Adapted from WHO).;
Alternative definition : CDISC: A benign neoplasm of ependymal origin.;