A brain tumor is an abnormal growth in or on the brain.
Brain tumors can either be benign or malignant.
A benign tumor is not cancerous and will not spread to other areas of the body. A malignant tumor is cancerous, which means it is made of abnormal cells that divide without control. Cancerous tumors invade and destroy surrounding tissue and can spread to other areas of the body. When located in the brain, both benign and malignant tumors are very serious. That is because as a tumor grows, pressure builds up in the brain.