Islet cell tumors belong to pancreatic endocrine tumors, with a low incidence rate of 4/100000 in the normal population. They originate from islet cells of the pancreas and mainly secrete insulin, however, with the application of immunohistochemistry, many of the tumors are actually mixed in nature, with different cells originating from pancreatic islets secreting various hormones, but with a certain one of them being predominant, and other hormones are not causing clinical symptoms due to small amount or no significant activity. In fact, many tumors are mixed, originating from different cells of pancreatic islets, secreting many kinds of hormones, but one of them is the main one, and other hormones do not cause clinical symptoms because of their small amount or no significant activity. The most common clinical tumor is the one originating from the islet’s b-cells, which accounts for about 70%-80% of the pancreatic endocrine tumors. Islet cell tumors can occur at any age, and are more common in young and middle-aged people, and there are more males than females. Whipple first described the typical symptoms of islet cell tumors in the 1930s, which is also known as Whipple’s triad: ① spontaneous periodic episodes of hypoglycemia, mostly after fasting or labor; ② episodes of glucose lower than 2.8 mmol/L; ③ symptoms relieved by oral or intravenous glucose. The symptoms are relieved after oral or intravenous administration of glucose, which is still used as a clinical criterion for the diagnosis of islet cell tumor. According to the typical recurrent hypoglycemic manifestations, Whipple’s triad, low serum insulin level at the time of seizure, and the ratio of blood glucose > 0.3, it is not difficult to diagnose islet cell tumor, but the specific clinical manifestations are various, and the clinical manifestations are non-specific, and they are initially misdiagnosed as cranial neurological diseases, or even psychiatric diseases, and they are not diagnosed and treated timely and effectively, and the hypoglycemic symptom episodes are becoming more and more frequent, and the organism is under severe hypoglycemia for a long time. The body is in a state of severe hypoglycemia for a long time, which can cause irreversible damage to the central nervous system. Therefore, early diagnosis and treatment are very important, but islet cell tumor is often small, and it is difficult to locate and diagnose, and at the same time, locating and diagnosing is also the key to surgical resection, therefore, it is very important to locate and diagnose islet cell tumor before surgery. The localization diagnosis of islet cell tumor mainly relies on imaging examination, and in the past, it was thought that islet cell tumors were mostly located in the body and tail part of the pancreas, but in fact, the incidence of pancreatic head, body, and tail parts were basically equal, and the size and function of the tumors were not necessarily in a positive proportion.Ultrasound, with the advantages of its non-invasive, inexpensive, convenient, and reproducible operability, can detect tumors with a diameter larger than 1 cm, and it is used as a routine inspection of islet cell tumor, but ultrasound has low sensitivity, especially the tumors. However, the sensitivity of ultrasound is low, especially when the tumor body is small, coupled with the fact that the patients are mostly obese, it reduces the detection rate of the tumor even more. In recent years, with the application of intraoperative ultrasonography (IOUS), the detection rate of tumor localization has been greatly improved. Experienced surgeons with intraoperative diagnosis and combined application of intraoperative ultrasound can detect small tumors with a diameter of less than 0.5 cm in deeper locations, which can not only find and locate the tumor, exclude or find multiple tumors, but also show the relationship between the tumor and the pancreatic duct. Intraoperative ultrasound can not only find and locate the tumor, but also exclude or detect multiple tumors, and show the relationship between the tumor and the pancreatic duct, bile duct, portal vein and superior mesenteric vein, which is conducive to the selection of the access route for resection of the tumor, reduce intraoperative hemorrhage and biliopancreatic duct injury, and prevent serious biliopancreatic leakage in the postoperative period, the clinical value of intraoperative ultrasound is increasing and is more important for the patients who cannot be localized for diagnosis in the preoperative imaging examination but have a clear diagnosis for the qualitative diagnosis of pancreatic islet cell tumors. The positive rate of CT and MRI for islet cell tumor is high, and the statistics of large number of cases in China show that the positive rates of B-ultrasound, CT and MRI are 33.5%, 45.8% and 59.5% respectively. The use of CT thin-layer (2mm) scanning and contrast-enhanced staging scanning can significantly increase the detection rate of the tumor, with obvious enhancement effect, manifested as homogeneous or ring-shaped enhancement, which is more characteristic of islet cell tumors, while the MRI examination shows that the application of different sequences combined with the dynamic enhancement scanning can be beneficial to the localization and diagnosis of the tumor. All of the above methods are non-invasive examinations, which should be fully applied and utilized in the clinic, so that the tumor can be optimally localized and diagnosed. Invasive methods include selective arteriography (DSA), percutaneous hepatic puncture, portal vein cannulation, segmental blood sampling for insulin measurement (PTPC), selective arterial calcium stimulation, venous blood sampling for insulin measurement (ASVS), etc. The positive rate of localization diagnosis of these methods is significantly higher than that of non-invasive methods, but their wide application in the clinic has been limited by their complex and invasive nature. think that too much preoperative localization examination is not necessary for islet cell tumors, as long as the clinical manifestations are typical and the diagnosis is clear, we can directly perform surgical exploration combined with intraoperative ultrasonography to locate and diagnose the tumors and at the same time perform surgical resection, however, we believe that we should try to locate the tumor as accurately as possible in order to avoid surgical blindness, in addition, with the continuous improvement of the current imaging technology, the selection of reasonable examination modalities, or the combination of the application of mutual complementary corroboration, can provide a good solution for the islet cell tumor. With the continuous improvement of imaging technology, the use of reasonable examination modalities, or the combined application of mutual corroboration, the preoperative localization of islet cell tumors is not quite difficult, and blind excision has been gradually discarded. The only effective way to treat pancreatic islet cell tumor is to completely remove the tumor by surgery, relieve the excessive secretion of hormone and alleviate the symptoms. For non-functional pancreatic islet cell tumors, the main purpose is to remove the tumor, alleviate the pressure of the tumor on the surrounding organs as well as the symptoms caused by the bleeding and infection that may occur in the tumor itself, and, more importantly, to prevent the tumor from further malignant changes and metastasis. Specific surgical methods are chosen according to the location and size of the tumor as well as its relationship with the surrounding tissues and organs. Pancreatic islet cell tumor mostly has complete peritoneum, and the boundary of normal pancreatic tissue can be cleared, most of the tumors can be resected locally and completely, and then pancreatic trauma can be closed, and it is advisable to carry out intraoperative ultrasonography before and after the resection, especially for those whose tumors lie deep in pancreatic tissues, to further clarify the location of tumors, and it is better to scan the whole pancreas except for the location of tumors, and to investigate whether there are any other tumors that are missed, and at the same time, it is also necessary to determine the relationship of tumors and main pancreatic ducts. At the same time, the relationship between the tumor and the main pancreatic duct and other structures should be determined, so as to avoid surgical damage to the main pancreatic duct and serious pancreatic leakage in the postoperative period. Blood glucose was measured every 15-30 minutes before surgery, before tumor resection, and after tumor resection until the blood glucose rose, and the tumor was immediately sent to rapid frozen section pathology after resection to confirm that it was a pancreatic endocrine tumor and was completely resected before the abdomen was closed. In this group, there was one case in which blood glucose did not rise continuously after tumor resection, and the ultrasound repeatedly scanned the pancreas and did not find any tumor residue, so a small amount of glucose was infused, and blood glucose was measured to rise, and then blood glucose was measured every 15-30 minutes for 1.5 hours, and blood glucose level did not fall before the end of the operation, and no hypoglycemia occurred in the postoperative testing of blood glucose. It should be noted that intraoperative rapid cryopathology can only determine whether the tumor is a pancreatic endocrine tumor, and postoperative paraffin pathology and immunohistochemistry can further clarify the specific nature of the tumor. The majority of resected pancreatic islet cell tumors showed the expression of a variety of neuroendocrine markers, and one of the cases showed the expression of 8 markers, and only 2 cases showed the expression of simple insulin positive expression, that is to say, simple insulin tumors are not rare. In other words, insulin-only tumors are not common, and insulin-based islet cell tumors with multiple hormone expression are more common, so the clinical manifestation is still typical of hypoglycemic reaction. For tumors located in the tail of the pancreas, it is feasible to resect the tail end of the pancreas within the tumor, and then close the pancreatic dissection, but tumors located here are often adjacent or even adherent to the splenic and splenic blood vessels, and attention should be paid to the protection of the tumor during surgery, especially the larger volume of non-functioning or malignant islet cell tumors are, and often need to be combined splenectomy, and there were five cases of combined splenectomy in this group of patients. Islet cell tumors located in the leptomeningeal part of the pancreatic head are the most difficult to deal with, because of the complex structure and rich blood flow here, and it is easy to damage the main pancreatic duct, bile duct, duodenum, and peripheral blood vessels, etc. Moreover, the damage to the main pancreatic duct here usually cannot be healed on its own, therefore, intraoperative ultrasound is fully applied during the operation to avoid damaging the above mentioned structures, and pancreatic head resection preserving the duodenum is performed if necessary, or even Whipple’s operation. The tumor is located in the neck of the pancreas. A part of the tumor is located in the near neck of the pancreas, or the pancreas itself is slender, plus the tumor is deep, after complete resection of the tumor, most of the pancreatic tissues are missing, and ultrasound confirms that the main pancreatic duct is obviously damaged, or even completely severed, at this time, the short end of the head of the pancreas can be closed, and attention should be paid to find the pancreatic ducts and ligature, and the caudal end of the pancreas and the jejunum should be pancreatic-intestinal Roux-en-Y anastomosis to keep most of the pancreatic tissues as much as possible, and maintain the internal and external secretory functions of the pancreas. The internal and external secretion function of the pancreas is maintained. The most common complication after surgical resection of pancreatic islet cell tumor is pancreatic leakage, and there were 18 cases of pancreatic leakage in this group, with an incidence rate of 28%, and one of them had a continuous pancreatic leakage for half a year, and it was considered that the larger pancreatic duct or even the main pancreatic duct might be damaged during the operation. In addition to surgical damage to the pancreatic duct, the cause of pancreatic leakage may be the excessive knotting and suturing of the pancreatic dissection, which leads to pancreatic tissue necrosis, detachment and even infection, resulting in pancreatic leakage. Generally, mild pancreatic leakage will be healed within a short period of time after adequate drainage and appropriate acid-suppressing treatment to inhibit pancreatic enzyme secretion. For patients who cannot be healed or have poor drainage, pancreatic pseudocysts or abscesses will be formed, and then ultrasound-guided puncture and tube placement will be performed to drain the pancreas, or even another operation will be needed. In order to prevent pancreatic leakage, in the process of surgical resection of the tumor, the periphery of the side resection are carefully ligated small pancreatic ducts and blood vessels, and then the trauma is carefully closed with non-invasive needles and threads, and it is important to place an effective drain on the pancreatic trauma and the drain is not easy to be removed prematurely until the daily drainage is less or disappears, and the drainage of fluid amylase <1500u< span="">, abdominal ultrasound confirms that there is no accumulation of fluid around the pancreas in the abdominal cavity before it is removed. Removal, while postoperative application of acid suppression, inhibition of pancreatic enzyme secretion drugs and antibiotics to prevent infection. After complete surgical resection of islet cell tumor, blood glucose rises rapidly, and a considerable part of patients will have obvious rebound elevation of blood glucose within a short period of time, and the cases in this group amounted to 85.9%, and the fasting blood glucose of a patient was as high as 29 mmol/L on the first day of the postoperative period, and it gradually decreased to the normal level on the 15th day of the postoperative period after the administration of low-glucose medication and the application of appropriate amount of insulin. This may be due to the long-term secretion of a large amount of insulin by islet cell tumor, which inhibits the insulin secretion of regular pancreatic islet b-cells. When the tumor was resected, the islet cells remained at a low secretion level for a short period of time, and under the continuous stimulation of high blood glucose, the b-cells gradually resumed normal secretion through the body’s self-regulation function, so as to maintain normal metabolism and use of glucose by the tissue cells of the organism. Moreover, the recovery time of postoperative blood glucose is positively correlated with the length of preoperative disease. Prolonged hyperglycemia after surgery is not conducive to the patient’s recovery and increases the occurrence of complications, so it is necessary to apply appropriate insulin to normalize the blood glucose when hyperglycemia occurs after surgery. The prognosis of complete resection of islet cell tumor is good, and the recurrence rate is low. It has been reported in the literature that postoperative recurrence is mainly caused by the surgical omission of multiple islet cell tumors, incomplete surgical resection, and ectopic islet cell tumors, etc. Therefore, accurate diagnosis of preoperative localization, careful exploration by ultrasound combined with intraoperative ultrasound, and complete and thorough resection of the tumor are the keys to the treatment of pancreatic islet cell tumors.