Background: Multiple endocrine neoplasia type 1 (MEN1), also called Wermer syndrome, is an autosomal dominant disorder characterized by tumors of the parathyroid glands, the anterior pituitary, and the endocrine pancreas.
Case Report: Here, we report a case of MEN1. Our patient was a 44-year-old woman who manifested typical features of MEN1, including insulinoma, pituitary tumors, and parathyroidoma, and exhibited multiple lipomas and a gastrinoma with duodenal ulcers. She was admitted to our hospital because of recurrent massive bleeding of the upper gastrointestinal tract and hypoglycemia. The first operation for pituitary tumors was performed when she was 40 years old. According to these examinations and her clinical course, the patient was diagnosed with insulinoma and gastrinoma. She subsequently underwent surgery for the pancreatic tumors. The majority of these tumor cells were immunohistochemically positive for insulin and negative for glucagon.
Conclusions: This case suggests that multiple lipomas, insulinoma and gastrinoma may provide clues for a diagnosis of MEN1.

Keywords: Multiple Endocrine Neoplasia Type 1, upper gastrointestinal bleeding, multiple lipomas, Insulinoma, Gastrinoma