Islet cell tumors are also known as islet cell adenomas. Tumors that occur in the islet cells of the pancreas. Pancreatic islet cell tumors are divided into two categories: functional and non-functional. Functional islet cell tumors are mainly insulinomas, which are formed by beta cells and are rare clinically, with an incidence of (3-4)/million according to foreign statistics. Pancreatic islets are composed of a variety of cells with different functions, and pancreatic endocrine tumors of different cellular origins exhibit different clinical symptoms. Islet cell tumors are named according to the main hormone they produce and mainly include insulinoma and gastrinoma. All pancreatic endocrine tumors are difficult to identify based on conventional histological examination and are determined to be malignant based on the presence or absence of local invasion, regional lymph nodes, liver or distant metastases. Insulinoma is a rare tumor derived from islet B cells, but it is the most common among pancreatic endocrine tumors, about 95% of which are benign, with a male to female ratio of about 2:1, distributed in the head, body, or tail of the pancreas, with a tumor diameter of 1-2.5 cm. Typical symptoms are spontaneous hypoglycemia in the early morning, which can also be triggered by delayed meals, exercise, exertion, mental stimulation or fever, etc. The symptoms are relieved after giving glucose. In order to avoid attacks, patients often become obese due to extra meals.