Every person’s situation is different, so researchers may not know the specific cause every time someone develops insulinoma. But insulinoma is associated with the following syndromes and conditions: Multiple endocrine neoplasia type 1 (MEN1): This is an inherited condition that affects your endocrine glands and your duodenum. Your duodenum is the first part of your small intestine. Von Hippel-Lindau syndrome: This is an inherited condition that causes tumors throughout your body. Neurofibromatosis type 1 (NF1): This condition affects your skin and nervous system. Tuberous sclerosis complex (TCS): This is an inherited condition that may cause epilepsy, tumors (usually benign) and skin growths.