Subependymoma is a rare and slow growing type of ependymoma, often presenting in middle-aged adults, found more commonly in men than in women, usually located in the fourth and lateral ventricles and manifesting with variable symptoms including headache, nausea, and loss of balance. In some cases it can be asymptomatic. It is usually associated with a better prognosis than other forms of ependymoma. The disease is subependymoma (MONDO_0007667). Also known as: SUBEPENDYMOMA, benign, WHO grade I ependymal neoplasm, WHO grade I ependymal tumor, WHO grade I ependymal tumour, mixed subependymoma-ependymoma, subependymal astrocytoma, subependymal glioma.