WHO 2021 CNS tumor classification now integrates molecular markers into diagnoses. IDH-mutant, 1p/19q co-deleted glioma with TERT promoter mutation is classified as:

• A Oligodendroglioma, IDH-mutant and 1p/19q-codeleted, CNS WHO grade 2 or 3 ✓
• B Astrocytoma, IDH-mutant, CNS WHO grade 2
• C Glioblastoma, IDH-wildtype, CNS WHO grade 4
• D Diffuse midline glioma, H3 K27M-mutant

Explanation

WHO 2021 CNS tumor classification defines oligodendroglioma by the triple combination: IDH mutation + 1p/19q co-deletion + TERT promoter mutation. This molecular signature is diagnostic regardless of histology and predicts sensitivity to PCV chemotherapy and relatively favorable prognosis. IDH-mutant gliomas without 1p/19q codeletion are classified as astrocytoma IDH-mutant (and frequently harbor ATRX mutation). Glioblastoma is IDH-wildtype with specific molecular features (EGFR amplification, +7/-10, TERT mutation). Diffuse midline glioma has H3 K27M mutation and arises in thalamus, brainstem, or spinal cord.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.