Table 1.

Terminology of IDH-mutant gliomas in the WHO classification of 2016 and 2021

WHO 2016	WHO 2021
Diffuse Astrocytoma WHO grade II, IDH-mutant	Astrocytoma, IDH-mutant CNS WHO grade 2
Anaplastic Astrocytoma WHO grade III, IDH-mutant	Astrocytoma, IDH-mutant CNS WHO grade 3
Glioblastoma WHO grade IV, IDH-mutant	Astrocytoma, IDH-mutant CNS WHO grade 4
Oligodendroglioma WHO grade II, IDH-mutant and 1p/19q-codeleted WHO grade II	Oligodendroglioma, IDH-mutant and 1p/19q- codeleted CNS WHO grade 2
Anaplastic Oligodendroglioma WHO grade II, IDH-mutant and 1p/19q-codeleted WHO grade III	Oligodendroglioma, IDH-mutant and 1p/19q- codeleted CNS WHO grade 3