IDH1 and central nervous system cancer: Three different tumor subtypes, related to IDH1-wildtype gliomas, have been identified: the “solid” one, characterized by small peritumoral infiltration, that can benefit from radical tumor resection; the “irregular” one, characterized by invasive behavior and a poor response to aggressive treatments, often located in the temporal lobe; and the “rim-enhancing” subtype, less vascularized, with a lower cell density and an enhanced peripheric rim.