Classification of adult-type diffuse gliomas: Impact of the World Health Organization 2021 update

Over the last decade, developments in molecular profiling have radically altered the diagnosis, classification, and management of numerous cancer types, with primary brain tumors being no exception. Although historically brain tumors have been classified based on their morphological characteristics, recent advances have allowed refinement of tumor classification based on molecular alterations. This shift toward molecular classification of primary brain tumors is reflected in the 2021 5(th) edition of the WHO classification of central nervous system tumors (WHO 2021). In this review, we will discuss the most recent updates to the classification of adult-type diffuse gliomas, a group of highly infiltrative and largely incurable CNS malignancies. It is our hope continued that refinement of molecular criteria will improve diagnosis, prognostication, and eventually treatment of these devastating tumors.

Automated summary

In the past decade, advancements in molecular profiling have significantly impacted the way cancer types, including primary brain tumors, are diagnosed, classified, and managed. Molecular alterations have allowed for a more refined classification of brain tumors, deviating from the traditional reliance on morphological characteristics. This shift towards molecular classification is evident in the 2021 WHO classification of central nervous system tumors. This review focuses on the recent updates regarding the classification of adult-type diffuse gliomas, which are highly infiltrative and mostly incurable malignancies of the central nervous system. The refinement of molecular criteria holds promise for improving the diagnosis, prognostication, and eventual treatment of these devastating tumors.