The 2016 WHO classification of primary central nervous system tumors: a clinician's view

Abstract

This article is devoted to the latest edition of the 2016 WHO classification of primary CNS tumors. The authors, who are clinicians and not morphologists, have tried to analyze and briefly present the main changes to the new edition of the WHO classification of primary CNS tumors, the main difference of which from the previous 2007 classification is inclusion of the molecular genetic features of primary CNS tumors in the classification criteria. The article focuses mainly on the classification issues of diffuse gliomas and glioblastoma, with assessment of the role of IDH-1,2, ATRX, TERT, and MGMT mutations as well as a 1p/19q co-deletion. The article briefly describes some new nosological forms (e.g., Grade III anaplastic pleomorphic xanthoastrocytoma) and presents a new approach to the classification of embryonic (medulloblastoma) and glial childhood tumors as well as tables of the main differences between 2016 and 2007 WHO classifications of primary CNS tumors. Based on their own clinical experience, the authors dispute with the described classification and suggest their own ideas for improving the classification of primary CNS tumors in the future.