The 2007 WHO classification of tumours of the central nervous system

Abstract

The fourth edition of the World Health Organization (WHO) classification of tumours of the central nervous 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, pituicytoma and spindle cell oncocytoma of the adenohypophysis. Histological variants were added if there was evidence of a different age distribution, location, genetic profile or clinical behaviour; these included pilomyxoid astrocytoma, anaplastic medulloblastoma and medulloblastoma with extensive nodularity. The WHO grading scheme and the sections on genetic profiles 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 classification is accompanied by a concise commentary on clinico-pathological characteristics of each tumour type. The 2007 WHO classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from more than 70 international experts overall, and is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities world-wide.

Fig. 1

Angiocentric glioma. a Elongated tumour cells with concentric perivascular arrangement. b Perivascular tumour cells strongly express GFAP. Courtesy of Dr. V. H. Hans

Fig. 2

Novel glioneuronal tumour entities. a Papillary glioneuronal tumour (PGNT). Layers of tumour cells surround vessels, forming pseudopapillary structures with b pseudopapillae covered by inner cells with hyperchromatic and outer cells with vesicular nuclei. Courtesy of Dr. Y. Nakazato. c Rosette-forming glioneuronal tumour of the fourth ventricle (RGNT). Pseudorosette with ring-like arrangement of neurocytic tumour cell nuclei around an eosinophilic neuropil core which d shows strong immunoreactivity to synaptophysin. Courtesy of Dr. J. A. Hainfellner

Fig. 3

Papillary tumour of the pineal region. a Histology shows the typical papillary architecture and epithelial cytology. b In papillary areas, the tumour cells are large with columnar or cuboidal shape. Courtesy of Dr. M. Fevre-Montange

Fig. 4

Pituicytoma with elongate, bipolar spindle cells arranged in interlacing fascicles. Courtesy of Dr. D. Brat

Fig. 5

Spindle cell oncocytoma. a Note spindle and somewhat epithelioid cells with abundance of variably granular cytoplasm, different degrees of nuclear atypia and focal inflammatory reaction. b Generalized staining for S-100 protein is a regular feature of this rare tumour

Fig. 6

Pilomyxoid astrocytoma showing a monomorphous population of tumour cells in a homogenously myxoid background with angiocentric accumulation