Gastrointestinal mesenchymal tumors are a group of tumors that originate from the mesenchymal tissue of the gastrointestinal tract, mostly in the stomach and small intestine, with metastases mainly in the liver and abdominal cavity. There is no specific clinical manifestation, and the course of the disease can be as short as a few days or as long as 20 years. Common symptoms include abdominal pain, masses and gastrointestinal bleeding and gastrointestinal obstruction. Immunohistochemical antibodies recommended for the differential diagnosis of GIST include: DOG1, CD117, CD34, α-SMA, desmin, and protein. Detection of KIT and PDGFR genes is recommended (there are four mutation types in KIT, exon 9 (10.3%), exon 11 (87.2%), exon 13 (2.1%), exon 17 (0.4%), and mutations in PDGFR occur in tumors without KIT mutations, with three mutation types exon 12 (3%), exon 14 (<1%), and exon (97%)). Enhanced CT, MRI and endoscopy or endoscopic ultrasound of the abdomen are recommended as adjuncts to the initial diagnostic evaluation. The standard of care for limited GIST is complete resection, and preoperative imatinib is recommended for patients in whom R0 resection is not feasible or in whom less disruptive surgery is possible to achieve R0 resection in the setting of cytoreduction For patients with locally advanced and metastatic GIST who are inoperable, imatinib is the standard of care and is also indicated for all patients with metastatic disease after complete resection of the lesion. Site Case presentation: the patient was female, 43 years old. Brief history: The patient had a sudden onset of mid-upper abdominal pain in August 2015, which was paroxysmal and could not be relieved by itself, so she was seen at a local hospital, and an ultrasound was performed in the emergency room, suggesting: abdominopelvic fluid, multiple intrahepatic occupations, and right renal parenchymal occupations. On 2015-08-19, the patient came to our hospital and underwent gastroscopy: malignant tumor at the junction of the descending duodenal bulb was possible. Later, a percutaneous puncture biopsy was performed, and the pathology suggested: GIST, kit detection, exon 11 mutation. 2015.08.21 abdominal MR: duodenal MT, GIST possible, multiple metastases in the liver. The patient was considered to have metastatic gastrointestinal mesenchymal tumor and was given oral Gleevec treatment.The patient started Gleevec 400mg Qd po.Facial edema (CTCAE grade) appeared 1 week after taking it and resolved on its own after one month.2015.10.08 CT check: duodenal wall thickening and mass shadow, MT considered; multiple hypodense nodules in the liver, metastasis partially considered.12.02 repeat MR check: compared with Compared with the previous CT (2015-10-8), the intestinal wall thickening of the lesion was slightly better than before, and the mass cystic change was more obvious than before; multiple intrahepatic metastases, some of which seemed to be slightly smaller than before. Experts from various departments had a lively discussion about the disease. Dr. Wang Xiaohong, deputy chief physician of radiology department, summarized the imaging manifestations after reviewing the films: the lesion in the duodenal bulb was a substantial mass mixed with a cystic lesion, exophytic in nature, without abdominal lymph node enlargement; the lesion was close to the kidney but without infiltration, and only invaded the surrounding fatty space; it was closely related to the large abdominal vessels but without obvious invasion. Metastases were considered in multiple lesions in the liver. Comparing the imaging examinations before and after treatment with Gleevec: the primary tumor lesions and intrahepatic metastases showed a tendency to become smaller, suggesting that the tumor was sensitive to Gleevec. Dr. Junyan Xu, attending physician of the Department of Nuclear Medicine, suggested that patients could undergo PET-CT examination to assess the biological characteristics of the tumor in combination with tumor morphology and metabolism. The use of PET-CT examination to assess the early efficacy of imatinib in the treatment of metastatic has a high sensitivity and is also significantly associated with the long-term outcome of patients. A repeat PET-CT examination after 24H of Gleevec may also suggest sensitivity of the lesion to Gleevec if the lesion has decreased isotope uptake. Meanwhile the significance of SUV value and glucose metabolism status, value, CNR value and ADC in evaluating the biological characteristics of GIST cannot be ignored. Dr. Yaohui Wang of the Department of Interventional Medicine suggested that: CT enhancement of multiple metastases in the liver is not obvious, suggesting that the blood supply is not abundant and interventional treatment is not recommended. Usually, radiofrequency ablation can be done for less than 3, each lesion is less than 3CM. For this patient, systemic treatment is recommended. Dr. Zhiyu Chen, deputy chief of medical oncology department, suggested that: lymphatic metastasis is rare, and small intestine origin is more malignant than gastric origin. At present, the patient's tumor has metastasized and aggressive surgery is not advocated (i.e., conventional extended resection or regional lymph node dissection is not advocated). The issues to be considered are: if this patient is operated, whether both primary and metastatic foci need to be R0 resected, whether the patient can benefit from resecting only the primary foci if the metastatic foci are not removed, and the timing of resecting the primary foci. Professor Chen pointed out that in general, surgery can be evaluated after six months of Gleevec treatment, or surgery can be recommended when the efficacy of Gleevec treatment reaches its maximum, that is, when the tumor is no longer regressing. Dr. Xu Jin, deputy chief of pancreatic surgery, suggested: The patient has no gastrointestinal bleeding, anemia, no obstruction, no perforation, so the indications for surgery are small; if surgery is performed, the right kidney lesion needs to be evaluated, whether it needs to be removed, etc. The scope of surgery is large, which is a big blow to the patient and the patient does not necessarily benefit; at present, Gleevec treatment is effective, so it is recommended that internal medicine is the main treatment. Summary by Dr. Yu Xianjian, Chief of Pancreatic Surgery: The nature and scope of GIST in this patient is clear. There is no indication for surgery for the time being; surgery is not beneficial because surgery may require removal of the unilateral kidney, and if postoperative recurrence occurs and the effect of Gleevec is not good enough to require drug replacement, the patient's tolerance to Sotan will be significantly weakened thus affecting the subsequent treatment; moreover, it is more favorable to surgery after the tumor regression by Gleevec treatment. Currently, Gleevec treatment can be beneficial and it is recommended to continue the drug for 3 months before evaluating whether to operate.