The fifth edition of the World Health Organization (WHO) Classification of Central Nervous System (CNS) Tumors was released in 2021, just five years following the updated fourth edition. Advanced molecular testing such as next-generation sequencing, RNA fusion analysis, and DNA methylation profiling has led to more precise grading and classification of pre-existing tumor types as well as the recognition of new ones. Herein, we outline the major updates of the 2021 WHO Classification of CNS tumors, with emphasis on the expanded molecular characterization of CNS tumors.

The fifth edition of the World Health Organization (WHO) Classification of Central Nervous System (CNS) Tumors was released in 2021, just five years following the updated fourth edition. Advanced molecular testing such as next-generation sequencing, RNA fusion analysis, and DNA methylation profiling has led to more precise grading and classification of pre-existing tumor types as well as the recognition of new ones. Herein, we outline the major updates of the 2021 WHO Classification of CNS tumors, with emphasis on the expanded molecular characterization of CNS tumors.

The fifth edition of the World Health Organization (WHO) Classification of Central Nervous System (CNS) Tumors was released in 2021, just five years following the updated fourth edition. Advanced molecular testing such as next-generation sequencing, RNA fusion analysis, and DNA methylation profiling has led to more precise grading and classification of pre-existing tumor types as well as the recognition of new ones. Herein, we outline the major updates of the 2021 WHO Classification of CNS tumors, with emphasis on the expanded molecular characterization of CNS tumors.