Newly Recognized CNS Tumors in the 2021 World Health Organization Classification: Imaging Overview with Histopathologic and Genetic Correlation

Abstract

In 2021, the World Health Organization released an updated classification of CNS tumors. This update reflects the growing understanding of the importance of genetic alterations related to tumor pathogenesis, prognosis, and potential targeted treatments and introduces 22 newly recognized tumor types. Herein, we review these 22 newly recognized entities and emphasize their imaging appearance with correlation to histologic and genetic features.ABBREVIATIONS: AT/RT ¼ atypical teratoid/rhabdoid tumor; cIMPACT-NOW ¼ Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy-Not Official WHO; GFAP ¼ glial fibrillary acidic protein; MAPK ¼ mitogen-activated protein kinase; NEC ¼ not elsewhere classified; NOS ¼ not otherwise specified; PFA and PFB ¼ posterior fossa ependymoma groups A and B; WHO ¼ World Health Organization; WHO CNS5 ¼ World Health Organization Classification of Tumors of the Central Nervous System, fifth edition; IDH ¼ isocitrate dehydrogenase