2016 Updates to the WHO Brain Tumor Classification System: What the Radiologist Needs to Know

Abstract

In 2016, the World Health Organization updated its classification system for brain tumors, making a number of changes pertinent to radiologists, including the elimination or redefinition of previously recognized tumors (eg, oligoastrocytoma, gliomatosis cerebri), the addition of new tumors (eg, diffuse leptomeningeal glioneuronal tumor), and the incorporation of genetic factors into the definitions of infiltrating gliomas. Radiologists play a key role in brain tumor diagnosis and management and must stay abreast of developments in the field to advance patient care and communicate with other health care providers. In 2016, the World Health Organization (WHO) released an update to its brain tumor classification system that included numerous significant changes. Several previously recognized brain tumor diagnoses, such as oligoastrocytoma, primitive neuroectodermal tumor, and gliomatosis cerebri, were redefined or eliminated altogether. Conversely, multiple new entities were recognized, including diffuse leptomeningeal glioneuronal tumor and multinodular and vacuolating tumor of the cerebrum. The glioma category has been significantly reorganized, with several infiltrating gliomas in children and adults now defined by genetic features for the first time. These changes were driven by increased understanding of important genetic factors that directly impact tumorigenesis and influence patient care. The increased emphasis on gene...