Adult brain tumors can be infratentorial and supratentorial and form from a variety of cells. Tumor types are classified using WHO grading based on morphologic and functional features. Tumor symptoms depend on tumor cell type, size and location. Diagnosis includes medical imagining, with a definitive diagnosis being made with a tissue biopsy. Treatments are largely dependent on the molecular characteristics and tumor grade, and can incorporate surgical removal and a combination of radiotherapy and chemotherapy.