In recent years, with the popularity of gastroscopy and colonoscopy, more and more people choose to do gastroscopy or colonoscopy, especially now that the pace of life is accelerating, young people work under pressure, irregular life, often abdominal pain, bloating, acid reflux and other kinds of abdominal discomfort, it is correct to go to a regular hospital to do a gastroscopy to clarify the cause of abdominal pain, because through gastroscopy, you can find a variety of stomach diseases. Of course most people’s gastroscopy results will be superficial gastritis, or reflux esophagitis, superficial erosive gastritis, etc. These are basically not a big problem and will slowly improve with improved lifestyle, regular diet, light and easy to digest diet, supplemented with acid suppressing drugs such as omeprazole. However, in some patients, gastroscopy may reveal small submucosal bulging lesions in the stomach wall, and further ultrasound endoscopy may reveal gastrointestinal mesenchymal tumor, which requires sufficient attention. So, what is gastrointestinal mesenchymal tumor? Gastrointestinal stromal tumor (GIST) is the most common mesenchymal origin tumor of the gastrointestinal tract, with the most common sites of development being the stomach and small intestine. The incidence of GIST can occur at any age, including infants and children. Large GIST has the characteristics of malignant tumor, which can easily spread and metastasize, and needs timely treatment, but how to deal with small GIST found by endoscopy? What is a small gastrointestinal mesenchymal tumor? At present, the expert consensus is that GIST with a diameter of <1cm is called "micro GIST", and GIST with a diameter of <2cm is collectively called "small GIST", such small tumors usually have no clinical manifestations, or mild abdominal discomfort. The diagnosis of this disease mainly relies on gastroscopy, colonoscopy and ultrasound endoscopy, and shows the characteristic of exophytic extra-mural growth. However, it should be noted that a small number of small gastrointestinal mesenchymal tumors also have malignant growth characteristics, and these tumors usually have the following manifestations during ultrasound endoscopy (EUS): irregular borders, cystic cavity, ulceration, strong echogenicity and inhomogeneous nature, meanwhile, compared with small gastrointestinal mesenchymal tumors occurring in the stomach, small gastrointestinal mesenchymal tumors occurring in the duodenum have the following manifestations Also, small gastrointestinal mesenchymal tumors occurring in the duodenum and small intestine are more prone to bleeding and perforation than small gastrointestinal mesenchymal tumors occurring in the stomach. Therefore, for the treatment of small gastrointestinal mesenchymal tumors, if there are no clinical symptoms and high-risk EUS features, including irregular border, cystic cavity, ulceration, strong echogenicity and heterogeneity, they can be left untreated and observed clinically, but endoscopic ultrasound should be reviewed every 6-12 months, while for small gastrointestinal mesenchymal tumors with clinical symptoms and high-risk EUS features, surgical resection should be performed. For small gastrointestinal mesenchymal tumors occurring with the duodenum and small intestine, an aggressive surgical approach is also taken. In hospitals with abundant endoscopic operation level, endoscopic resection can be adopted, but rupture and spread of tumor should be avoided. Meanwhile, laparoscopic surgical resection is being used more and more at present, which has the advantages of less trauma and faster recovery compared with open surgery. Discover the disease and treat it positively and correctly to get more health. Although the stomach disease is small, don't avoid the disease and don't panic and fear, with the right understanding and treatment, it is the good way.