CDKN2A and central nervous system neoplasm: The 2021 WHO Classification of CNS Tumors has integrated select molecular parameters into the grading of meningiomas, with TERT promoter mutation or CDKN2A/B homozygous deletion now sufficient for a CNS WHO grade 3 (anaplastic) designation.2 These alterations are present in only a small number of meningiomas and, therefore, the vast majority of meningiomas are graded solely by histology.