The 2007 WHO ClassiWcation of Tumours of the Central Nervous System

The fourth edition of the World Health Organi- zation (WHO) classiWcation of tumours of the central ner- vous system, published in 2007, lists several new entities, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicy- toma and spindle cell oncocytoma of the adenohypophysis. Histological variants were added if there was evidence of a diVerent age distribution, location, genetic proWle or clini- cal behaviour; these included pilomyxoid astrocytoma, ana- plastic medulloblastoma and medulloblastoma with extensive nodularity. The WHO grading scheme and the sections on genetic proWles were updated and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes typically involving the nervous system. As in the previous, 2000 edition of the WHO 'Blue Book', the classiWcation is accompanied by a concise com- mentary on clinico-pathological characteristics of each tumour type. The 2007 WHO classiWcation is based on the consensus of an international Working Group of 25 pathol- ogists and geneticists, as well as contributions from more than 70 international experts overall, and is presented as the standard for the deWnition of brain tumours to the clinical oncology and cancer research communities world-wide.