2000 World Health Organization classification of tumors of the nervous system.

This is a review of the 2000 World Health Organization (WHO) classification of tumors of the nervous system. It contains an overview of the most important changes and short descriptions of the new entities or variants of already existing entities included in the current classification. These are: chordoid glioma of the third ventricle, cerebellar liponeurocytoma, large cell medulloblastoma, medulloblastoma with extensive nodularity and advanced neuronal differentiation, atypical teratoid/rhabdoid tumor, perineuroma, and rhabdoid meningioma. In contrast to the former WHO tumor classification series, the present one is based on the complex criteria, which include not only the clinical course and histologic appearance of the neoplasm but its immunophenotypic features and molecular/cytogenetic profile as well. Thus, it is strongly disease-oriented and uses extensively the recent advances in the basic sciences.