Diffuse gliomas (IDH mutation)

Typical mutations

IDH mutation, ATRX loss, TP53 mutation, CDKN2A/B homozygous deletion, 1p-19q codeletion, H3K27 & H3.3G34R mutation, TERT mutation, EGFR amplification.

Chart

IDH Mutant

• Astrocytomas (Diffuse) – Typically IDH mutant.
  • IDH mutant ATRX loss / TP53 mutant
  • IDH mutant ATRX and TP53 intact
  • Astrocytoma WHO grade 4 =
    • CDKN2A/B homozygous deletion or
    • Microvascular proliferation, necrosis in CDKN2A/B wildtype (Otherwise grade 2 or 3)
• Oligodendrogliomas – Typically IDH mutant + 1p/19q codeleted.
  • WHO grade 2 or 3

IDH Wildtype (all are WHO grade 4)

• Diffuse midline gliomas – IDHwild with H3K27 mutant.
• Diffuse hemispheric glioma IDHwild with H3.3G34 mutant.
• Glioblastoma – IDH, H3 Wildtype (Only adult glioma in IDH wildtype family)

Reference