Benign Brain Tumors
Medical Author: Charles Davis, MD, PhD
Medical Editor: Melissa Conrad Stöppler, MD
Benign brain tumors are usually defined as a group of similar cells that do not follow normal cell division and growth patterns and develop into a mass of cells that microscopically do not have the characteristic appearance of a cancer. Most benign brain tumors are found by CTor MRIbrain scans. These tumors usually grow slowly, do not invade surrounding tissues or spread to other organs, and often have a border or edge that can be seen on CT scans. These tumors rarely develop into metastatic (cancerous or spreading) tumors. Most benign brain tumors can be removed; the benign tumors usually do not reoccur after removal. The exact causes of benign brain tumors are not known, but investigators have suggested that family history, radiation exposure, or exposure to chemicals (for example, vinyl chloride, formaldehyde) may be risk factors.
Benign brain tumors, however, can be life threatening because they can compress brain tissue and other structures inside the skull, so the term "benign" can be misleading. Terminology is further complicated by some investigators who classify low-grade cancerous tumors as either "benign" or "relatively benign." Regardless, compression of brain tissue or its additional structures (for example, nerves, ventricles) by a tumor mass is a major cause of the symptoms seen with benign (and malignant) tumors.