Intraductal papillary mucinous neoplasm of the pancreas is a cystic tumor of the pancreas that has been recognized in recent years. There have been different names for this tumor, such as mucus-producing carcinoma, hypersecreting mucus carcinoma, intraductal papillary tumor, ductal hypersecreting mucus tumor, intraductal carcinoma, ductal mucus-producing tumor, ductal extended mucinous cystadenoma and cystadenocarcinoma, mucinous ductal extension disease, pancreatic ductal extended mucus-producing tumor, and intraductal papillary mucinous tumor of the pancreas. The International Pancreatic Cancer Study Group, WHO, the U.S. Army Institute of Pathology and the Japanese Pancreatic Cancer Treatment Statute all collectively refer to those with pancreatic ductal epithelial papillary proliferation, mucus overproduction or both as IPMT and it has become a widely accepted concept internationally. Nowadays, intraductal papillary mucinous neoplasm of the pancreas is the term that is adopted today to avoid confusion with other mucinous producing tumors of the pancreas such as mucinous cystic adenoma or cystic adenocarcinoma of the pancreas. In 1996, the WHO classification method clarified the histological classification of IPMT into benign (intraductal papillary mucinous neoplasm), junctional (intraductal papillary mucinous adenoma with moderate atypical hyperplasia) and malignant (intraductal papillary mucinous carcinoma). The current nomenclature of IPMT is designed to avoid confusion with other mucus-secreting tumors of the pancreas such as mucinous cystic tumor of the pancreas (MCT), which tends to disseminate within the pancreatic ducts and the dilated pancreatic ducts are covered by papillary tumor epithelium. According to the origin of the tumor, IPMT is usually divided into three types: (1) main pancreatic duct type: the main pancreatic duct is dilated and the tumor is mainly present in the main pancreatic duct; (2) branch pancreatic duct type: the branch pancreatic duct is dilated and the tumor is not present in the main pancreatic duct; (3) mixed type: the tumor is present in both the main pancreatic duct and the branch pancreatic duct. The current study shows that IPMT and MCT have the following common features: (i) both tumors originate from the pancreatic duct epithelium; (ii) both produce large amounts of mucin; and (iii) both have the pathological feature of papillary protrusion. The clinical features of IPMT include: (i) massive mucus production and retention in the pancreatic ducts; (ii) enlargement of the opening of the mucus in the lacking papilla due to mucus flow; (iii) development and dissemination mainly in the main pancreatic duct; (iv) little tendency to infiltrate; and (v) high surgical resection rate and good prognosis. The basic pathological changes of IPMT are abnormal mucus-secreting epithelium in the pancreatic duct leading to massive mucus retention, pancreatic fluid stasis and dilation of the pancreatic duct, which may extend along the surface of the pancreatic duct to form flat lesions, or may be arranged to form micropapillary or macropapillary lesions protruding into the lumen of the pancreatic duct. Histologically, the proliferating epithelium is often more than twice the size of normal cells and transitions from non-papillary to papillary hyperplasia. These changes suggest that IPMT includes the evolution from non-papillary and papillary hyperplasia to adenocarcinoma via adenoma. In contrast, the majority of MCT histology has an ovarian-type stroma, which is often round in shape, has a common envelope, is usually without dilatation of the main pancreatic duct, and is completely surrounded by fibrous tissue, and is usually seen in middle-aged women and in the tail of the pancreatic body. However, a small number of IPMT and MCT still present difficulties in pathological diagnosis. It is common in the elderly, most often in the age group of 60-70 years, with a male:female ratio of about 2:1. It is generally believed that IPMT has no specific clinical manifestations at the early stage, but may present with abdominal pain, low back pain, wasting, jaundice, diarrhea, etc. Kimura et al. summarized the data of 259 patients with IPMT in Japan, Europe, and the United States and found that 51.8% had epigastric pain, 13.0% had weakness, and 13.0% had poor appetite. In addition, a small number of patients may develop jaundice, but its incidence is much lower than that of general pancreatic cancer. We reported that 23 of 43 patients with IPMT had clinical symptoms, including 12 cases of abdominal pain, 5 cases of low back pain, 2 cases each of weight loss, diabetes mellitus and amylase elevation, and up to 58.6% of patients had a history of pancreatitis, which may be due to the accumulation of large amounts of mucus in the pancreatic duct, resulting in high pressure in the pancreatic duct, rupture of small alveoli, and activation of pancreatic enzymes due to the overflow of pancreatic fluid, thus causing recurrent pancreatitis. The recurrence of pancreatitis was caused by the activation of pancreatic enzymes due to the overflow of pancreatic fluid. In addition, 41.4% of patients have diabetes mellitus. Therefore, patients with recurrent episodes of pancreatitis and diabetes mellitus should be alerted to prevent misdiagnosis and underdiagnosis. Patients with IPMT have a certain family genetic tendency and are often associated with malignant tumors of other organs, and it has been reported that up to 35% of patients with IPMT are associated with malignant tumors of other organs, suggesting that the genes associated with the occurrence of IPMT deserve further study. On CT imaging, it mainly appears as a cluster of grape bunches or lobulated cystic lesions with obvious dilatation of the pancreatic duct, which is connected to the pancreatic duct. The main difference between IPMN and other cystic tumors of the pancreas is that the cystic lesions of IPMN are connected to the dilated pancreatic duct. One of the main differences between IPMN and other pancreatic cystic tumors is that the cystic lesions of IPMN are connected to the dilated pancreatic duct, while other pancreatic cystic tumors are not connected to the pancreatic duct. MRI can show that the main pancreatic duct type T2WI shows a high signal dilated main pancreatic duct with diffuse dilatation, segmental dilatation and some isosignal wall nodules with an average diameter of about 1 cm (015 cm to 2 cm). The branched type presents as a grape bunch or a single long T1-long T2 signal tumor with an average diameter of 6 cm (2 cm to 9 cm) and some of them have wall nodules with an average diameter of about 2 cm (1 cm to 4 cm). The tumor is often associated with varying degrees of pancreatic atrophy and case calcification, or with dilatation of the main pancreatic duct. Enhanced MRI shows significant enhancement of the wall nodules. It also clearly shows the traffic between the branched type and the main pancreatic duct. ERCP shows enlarged large papilla with mucus flow, localized or diffuse main pancreatic duct dilatation and cystic dilatation of the branching pancreatic ducts, and filling defects due to the presence of wall nodules. In addition, ERCP can also be used to diagnose the fluid in the bursa and pancreatic ducts by aspiration under ultrasound guidance. For cases that are difficult to differentiate from pancreatic cancer or chronic pancreatitis, ERCP can be the gold standard, and transoral pancreatic ductoscopy can be used to observe polyp-like masses in the main pancreatic duct or villi-like changes in the pancreatic duct mucosa. Intraductal ultrasound (IDUS) is complicated and not yet popular. However, data show that the detection rate of nodular lesions, the detection of multiple lesions and the qualitative diagnosis rate of IDUS are higher than that of ultrasound endoscopy (EUS). IPMT is very easy to be misdiagnosed: the clinical symptoms are not distinctive, and the degree of dilation of the duct and the amount of mucus produced determine the clinical symptoms and signs. (1) IPMT is not specific in terms of clinical symptoms and laboratory tests, so the diagnosis is mainly based on imaging and postoperative pathology. (2) The diagnosis of IPMT should be considered when the CT shows a lobulated or nodular cystic pancreatic mass with dilated pancreatic ducts. If possible, ERCP examination can be performed, and if the enlarged duodenal papilla, significant abnormal dilatation of pancreatic duct and mucus overflow are found, the clinical diagnosis can be made. Once the diagnosis of IPMT is clear, surgical resection is the treatment of choice. However, it is still difficult to determine the preoperative benignity and malignancy of IPMT, and to determine the extent and degree of tumor invasion, so the choice of surgical method is still controversial. It is generally believed that the preoperative consideration of benign IPMT favors surgical options that preserve pancreatic and gastrointestinal functions, including pylorus-preserving pancreaticoduodenectomy (PPPD), duodenal-preserving pancreatic head resection, localized pancreatic hook resection, segmental pancreatic resection, and spleen-preserving pancreatic tail resection. If preoperative or intraoperative IPMT lesions are found to extend along the pancreatic duct, the extent of resection can be determined by intraoperative frozen section to ensure negative margins. For junctional IPMT or non-invasive malignant IPMT, partial pancreatectomy can be performed. In malignant cases, lymph node metastasis and nerve invasion may occur, so pancreaticoduodenectomy, total pancreatectomy or pancreatic tail resection and regional lymph node dissection are required for invasive cancer to reduce the recurrence rate of tumor after surgery. Since total pancreatectomy is very traumatic and seriously affects the postoperative quality of life, it is usually used only for patients with total pancreatic ductal lesions. If the risk of additional resection is estimated intraoperatively, partial resection is feasible if there is only heterogeneous hyperplasia at the severed end without infiltrating cancer. Duodenal papilloplasty can help mucus drainage and relieve symptoms, but only in cases that cannot tolerate pancreatectomy. Because of the significant differences in biological behavior and prognosis between IPMT and pancreatic ductal adenocarcinoma, the