The WHO classification of tumours of the central nervous system is a World Health Organization Blue Book that defines, describes and classifies tumours of the central nervous system (CNS).
Currently, as of 2023, clinicians are using the 5th edition, which incorporates recent advances in molecular pathology.[1] The books lists ICD-O codes, CNS WHO grades and describes epidemiological, clinical, macroscopic and histopathological features, among others.[2] The following is a simplified (deprecated) version of the fifth edition.