(BAY-tuh sel TOO-mer … PAN-kree-us)

An abnormal mass that grows in the beta cells of the pancreas that make insulin. Beta cell tumors of the pancreas are usually benign (not cancer). They secrete insulin and are the most common cause of low blood sugar caused by having too much insulin in the body. Also called beta cell neoplasm, insulinoma, and pancreatic insulin-producing tumor.