WHO 2021CNS Tumor Molecular Framework
Pathologic Diagnosis
Molecular Rule
In the WHO 2021 classification, Glioblastoma is now defined as an IDH-wildtype diffuse glioma in adults. An IDH-mutant glioma can no longer be called a "glioblastoma," even if it has necrotic features—it is now classified as an Astrocytoma, IDH-mutant, Grade 4.
Guidelines & Evidence
Verified
Last Review: 2026
Last Comprehensive Review: 2026
