In IDH-mutant_1p/19qret glioma, the presence of AB/FS mismatch was closely related to the presence of T2/FLAIR mismatch, suggesting the presence of a more fluid-like compartment (probably micro-cysts, which are observed extracellularly in astrocytomas and intracellularly in oligodendrogliomas) but further studies are needed to explain the factors contributing to our results. This evidence concerns the gene IDH2 and astrocytoma (excluding glioblastoma).