Table 3.

Grading criteria for astrocytomas, IDH-mutant

CNS WHO grade	Criteria
2	Well differentiated and lacks histological features of anaplasia
	Mitotic activity is not detected or very low
	Microvascular proliferation, necrosis, and homozygous deletions of CDKN2A and/or CDKN2B are absent
3	Focal or dispersed anaplasia
	Significant mitotic activity
	Microvascular proliferation, necrosis, and homozygous deletions of CDKN2A and/or CDKN2B are absent
4	Microvascular proliferation, necrosis or homozygous deletion of CDKN2A and/or CDKN2B