IDH1 and glioma: In STS, these rare subtypes included high-grade diffuse glioma of the midline/posterior fossa: H3/IDH-wildtype; diffuse high-grade neuroepithelial tumor (adult-type, non-defined types B and D); and diffuse pediatric-type high-grade glioma, H3 wildtype and IDH-wildtype, subtype A&B (novel).