IDH1 and pleomorphic xanthoastrocytoma: In general, an absence of molecular features of glioblastoma should prompt additional molecular testing (e.g., testing for BRAF alterations, testing for histone mutations, and methylome profiling) to achieve a specific diagnosis and to exclude the presence of other IDH-wt gliomas, such as diffuse midline glioma neuroepithelioid tumors, ganglioglioma, pleomorphic xanthoastrocytoma (PXA), and pilocytic astrocytoma [2].