A WHO grade II, slow growing tumor of children and young adults, usually located intraventricularly. It is the most common ependymal neoplasm. It often causes clinical symptoms by blocking cerebrospinal fluid pathways. Key histological features include perivascular pseudorosettes and ependymal rosettes. (WHO). The disease is ependymoma (Monarch Disease Ontology identifier MONDO_0016698). Also known as: benign ependymoma, epithelial ependymoma.