Integrated phenotype–genotype approach in diagnosis and classification of common central nervous system tumours

After nearly a century of histological classification of central nervous system tumours, the 2016 revised WHO classification has incorporated molecular features with clinical and prognostic relevance into brain tumour classification. In this review, we discuss the latest integrated phenotype-genotype approach to the most common intrinsic brain tumours in adults and children. The key genetic mutations and abnormalities, essential to the definition of these tumours, in line with the current WHO classification are described. Practical dilemmas, including 'difficult' tumours, the utility of DNA methylation classifiers and relevant recent advances post-WHO 2016 consensus are also discussed.