MEN1 and multiple endocrine neoplasia type 1: Multiple endocrine neoplasia type 1 (MEN1) is a disease that results from the inactivation of the menin tumor suppressor gene. It is inherited in an autosomal dominant manner. MEN1 is characterized by parathyroid adenomas, pancreatic islet tumors, and tumors of the anterior pituitary gland [10]. It has an estimated prevalence of 1-10 per 100,000 individuals [11].