Surgical Management of Low Grade Glioma

lower-grade gliomas histological diagnosis has had a long history, each iteration of disease classification suffered from continued variability, with detrimental consequences on prognostic precision and treatment decision making. In the WHO 2021 classification, there are three primary categories of adult-type diffuse gliomas: isocitrate dehydrogenase (IDH)-mutant, 1p/19q codeleted oligodendroglioma; IDH-mutant, non-codeleted astrocytoma; and IDH-wildtype glioblastoma. Diffuse low-grade glioma is classified as WHO grade 1 and 2 astrocytoma with IDH mutation or oligodendroglioma with IDH mutation and 1p/19q codeletion. The presence of the IDH1 mutation has become a defining factor for adult diffuse low-grade glioma. Roughly 70% of grade 2-3 gliomas harbor mutations in either IDH1 or its mitochondrial counterpart IDH2. Although lower-grade gliomas may present in various ways, the most common manifestation is seizures, and the development of seizures during the course of the disease may herald tumor progression. Among grade II tumors, the incidence of epilepsy is higher with IDH mutation. Anaplastic gliomas are somewhat less likely to manifest with seizures (57%) and are more likely than grade II gliomas to produce mental status, vision, and motor deficits.