The cause of benign brain tumors is unknown.

Benign tumors can interfere with body functions, but do not spread to distant areas of the body. Malignant, or cancerous, tumors invade or destroy normal body tissue. Their cells break away from the original tumor and spread to other parts of the body.

A benign brain tumor can cause symptoms and damage by inflammation, compression of various parts of the brain, and by increasing pressure inside the skull (hydrocephalus).