Wesentliche Neuerungen in der 2000 revidierten Fassung der WHO Klassifikation der Tumoren des Nervensystems

New developments in neuro-oncology have prompted an update of the World Health Organization (WHO) classification of tumors of the nervous system. Major changes include the addition of new entities and the refinement of criteria for the diagnosis and grading of various neoplasms, in particular the meningiomas. As novel clinico-patholog- ical entities, the chordoid glioma of the third ventricle, the atypical teratoid/rhabdoid tumor (AT/RT), the solitary fibrous tumor, and the perineurioma have been listed.The former lipomatous medulloblastoma of the cerebellum, previously incorporated in the family of embryonal tumors, is now classified as cerebellar liponeurocytoma.The term mixed pineocytoma/pineoblastoma has been replaced by pineal parenchymal tumor of intermediate differentiation. Furthermore, the large cell medulloblastoma and the tan- ycytic ependymoma were established as novel tumor variants. A separate chapter on the peripheral neuroblastic tumors has now been included in the classification. Substan- tial revisions were introduced in the menin- gioma chapter. For both atypical meningio- ma WHO grade II and anaplastic meningio- ma WHO grade III, histopathological criteria are now precisely defined. An important new addition to the WHO 2000 classification of nervous system tumors is the inclusion of molecular pathology findings.With this com- bination of pathology and genetics it has set the stage for a new format of the WHO tumor classification series.