Primitive Neuroectodermal Tumors: Views on a Working Classification

Abstract

The classification of brain tumors began many years ago with Bailey and Cushing (1926). Surprisingly few fundamental alterations have been made to their system of nomenclature, although numerous modifications have been suggested. Because of the proliferation of individual classifications, in 1979 the World Health Organization (WHO) sponsored publication of histologic typing of central nervous system tumors produced by a consensus of neuropathologists (Zülch 1979). This system, based on hematoxylin-eosin staining (H&E), was expected to be a working classification. In 1985 a modification of the WHO classification was suggested, reflecting the views of neuropathologists dealing primarily with brain tumors in children (Rorke et al. 1985).