In almost all patients with tumors in the central nervous system, the etiology is unknown.
In some cases, hereditary factors play a role. Individuals exposed to ionizing radiation also may have an increased risk for developing tumors in the central nervous system.
Children who are radiated for brain tumors have an increased risk for developing a new malignant condition, especially a new brain tumor. The risk after radiation increased with time, from 2.5% in the first ten-year period to 20% after 40 years.