Recognizing the significant impact of IDH mutation on the biology of astrocytic gliomas, cIMPACT-NOW update 5 has recently recommended a terminology “astrocytoma, IDH-mutated, grade 4” for the IDH-mutated diffuse astrocytic gliomas with histological/molecular features of glioblastoma, histological diagnosis over-ridden by molecular features [7]. This evidence concerns the gene IDH1 and astrocytoma (excluding glioblastoma).