Oligodendrogliomas are tumors that arise from oligodendrocytes. They have diffuse infiltration and involve the white matter and cerebral cortex of the frontal and temporal lobes. Pathologically, they are characterized by round nuclei with perinuclear halos, with a classic "fried egg" appearance. Oligodendrogliomas are defined by molecular characteristics including isocitrate dehydrogenase (IDH 1/2) mutation and co-deletion of chromosomal arms of 1p and 19q. These tumors may be low grade (World Health Organization [WHO] grade II) or anaplastic (WHO grade III).

Most oligodendrogliomas occur in patients aged 20-50. Low-grade tumors are more common in younger patients. Seizures are a common presentation. Headaches and focal neurologic symptoms may occur but are uncommon clinical presentations. These are slow-growing tumors and may be clinically silent for years. Median survival ranges from 5-15 years. Survival is longer in younger patients, those with a complete resection, and those with lower-grade tumors.