What Are Brain Tumors?

A brain tumor is an abnormal collection of cells in the brain that grow uncontrollably and form a mass. These tumors can be benign (noncancerous), or malignant (cancerous). Malignant tumors can invade nearby tissue and spread to other parts of your body. Benign tumors do not spread, but depending on their size and location, they can cause symptoms by pressing on surrounding brain tissue.

Brain tumors are classified as either primary or metastatic. Primary brain tumors originate inside your brain or its immediate surroundings. Metastatic brain tumors originate in other parts of your body.