RE: Comments on cIMPACT‐NOW Update 11

several areas warrant refinement to improve clarity, consistency, and alignment with WHO CNS5: (cid:129) Clarification of the age cut-off discrepancy for GBM diagnosis in IDH1 p.R132H-negative diffuse gliomas with GBM features, non-midline location, and without a history of a pre-existing lower-grade glioma. (cid:129) Clarification whether a descriptive diagnosis in IDH-wildtype diffuse gliomas with TERT -promoter mutation as the solitary finding in the absence of classic GBM histology is recommended only in low-grade astrocytic gliomas or also in cases with higher-grade histological features. (cid:129) Clarification of the sufficiency of methylation family (vs. class) match in the diagnosis of GBM and pHGG. (cid:129) Reassessment whether EGFR / PDGFRA -alterations suffice for pHGG, NOS diagnosis in patients <25 years without methylation profiling. (cid:129) Critical evaluation of reliance on PFSE methylation class assignment for “ posterior fossa ependymal tumor with TERT -promoter mutation and/or chromosome 6 loss. ” (cid:129) Reinstatement of HGVS-compliant nomenclature to promote international consistency and reproducibility. Addressing these issues would strengthen diagnostic precision, enhance consistency with WHO CNS5, and ultimately support improved diagnostics and patient care.