Clinical features GIST is a mesenchymal tumor of the gastrointestinal tract and mostly shows positive immunohistochemical staining for CD117. It can occur in all age groups with a peak age of 50-70 years. The younger the age of onset, the greater the likelihood of malignancy. It can develop in both men and women. The incidence of GIST in the gastrointestinal tract is in the order of stomach > jejunum > ileum > duodenum > rectum > colon. The symptoms of GIST are related to the location, size and growth pattern of the tumor. The most common symptom is vague abdominal pain and discomfort, which may also manifest as ulcers or bloody stools. Other rare symptoms include indigestion, loss of appetite, weight loss, nausea, and intestinal obstruction. Some patients may have no symptoms at all. It can also be detected occasionally during physical examination without any symptoms or signs. GIST in low rectum can be palpated by anal examination. Etiology c-kit is a proto-oncogene. In GIST, functionally acquired mutations occur in the c-kit gene, which expresses specific CD117/KIT antibodies (c-kit proto-oncogene related protein) on immunohistochemistry. The mutation disables the anti-apoptotic mechanism of cells and promotes rapid tumor cell growth. In GIST, there is a small proportion of undetectable mutations in the C-kit gene. It was found that PDGFR-α mutation is also an important etiology for the development of GIST. Indications for surgery for GIST In principle, complete resection should be performed surgically for lesions that are limited and have a maximum diameter of ≥2 cm. GlST that is difficult to be completely resected can be resected after tumor shrinkage by neoadjuvant targeted therapy. For tumors with a maximum diameter of <2 cm, there is no complete consensus. Surgery may also be considered if the lesion is complicated by bleeding, obstruction or perforation. The decision to perform adjuvant therapy is based on the post-excisional risk classification. Risk classification after primary GIST resection Surgical principles Intraoperatively, the integrity of the tumor envelope should be ensured. Mesenchymal tumor is fragile, and tumor implantation and metastasis may occur after rupture, which may seriously affect the prognosis. If the tumor invades adjacent tissues and organs, the tumor should be excised in its entirety along with the invaded and adherent tissues and organs. lymph node metastasis rarely occurs in GIST, and routine debulking is not necessary unless there are clear signs of lymph node metastasis. Rectal mesenchymal tumors have special features due to anatomical and physiological aspects. Intraoperative dissection of rectal mesenchymal tumors is extensive and affects the nerves, resulting in difficulty in defecation and urination after surgery. For smaller rectal mesenchymal tumors, local excision can be performed with the premise of ensuring R0 resection. With the introduction and application of targeted drugs such as imatinib mesylate in recent years, according to NCCN guidelines and ESMO guidelines, it is considered that drug therapy is needed before surgery to preserve function as long as function may be affected.