Adult intracranial ependymoma is a relatively rare brain tumour entity, accounting for 2-5% of all intracranial neoplasms. The pertinent prognostic factors as well as the pattern of recurrence remain to be elucidated. According to several recent reports, the prognostic value of Karnofski performance status, tumour location, the extent of surgical removal, histological grade and even postoperative radiotherapy remain controversial. As a consequence, optimal therapeutic management of adult intracranial ependymomas remains an ongoing debate. For this reason, a retrospective study conducted by the French society of neurosurgery (SFNC), neuropathology (SFNP) and the association of the neuro-oncologists of French expression (ANOCEF) was undertaken and allowed to collect 258 cases coming from 25 centers, initially diagnosed as intracranial ependymomas between 1990 and 2004. Clinical and follow-up data of these patients are known and the paraffin embedded samples as well as the frozen tissues available have been centralized. Central pathological review of these 258 cases was conducted by two senior neuropathologists and confirmed the diagnosis of ependymoma in 152 cases, thus constituting the most important series of the literature. Few molecular studies were carried out on ependymomas. The investigators have the opportunity, based on this important series, to determine the clinicopathological criteria and the molecular markers who will allow a better characterization of the diagnosis and the prognosis of these tumors.