The 52-year-old female patient was admitted to our hospital because of repeated black stool for more than 1 wk. There is nothing special about her family history and past history. The patient underwent endoscopy twice due to melena, and metal clip was used to stop bleeding after initially found the ruptured hemorrhage of ectopic varices in duodenal horizontal part. Gastrointestinal hemorrhage recurred later, with suspected submucosal eminence at the bleeding site. Abdominal computed tomography (CT) revealed huge duodenal stromal tumor, which was then surgically removed and confirmed pathologically. She had no gastrointestinal inflammation, ulcer or solid tumor before. Other history could cause gastrointestinal hemorrhage, such as medication and alcoholism, were excluded. Her family history has nothing notable. She had an anemic appearance, a flat and soft abdomen without tenderness, rebound pain or muscle tension. The results showed positive stool occult blood test and severe anemia (hemoglobin 45 g/L). Albumin was assessed at 33.3 g/L, fibrinogen was 4.53 g/L, and no significant abnormality was found in tumor markers or other routine examinations. The first endoscopy was performed in the outer hospital, revealed that multiple ectopic varices in the horizontal part of duodenum, with a diameter of about 0.5 cm to 0.8 cm. Rupture accompanied by active hemorrhage could be seen on the surface of varices, and three metal clips were used for hemostasis. Gastroscopy in our hospital showed that there was residual metal clip in the horizontal part of duodenum and bleeding was still active locally. We applied two metal clips to stop bleeding. In addition, suspicious submucosal bulges were found in varicose vein areas, which was hard when touched by biopsy forceps and lacked obvious mucosal glide motion. Abdominal CT revealed lumpy soft tissue density shadow in the horizontal part of duodenum, with a size of about 7.0 cm × 4.8 cm × 5.7 cm. Pathologically, the postoperative specimens were confirmed to be duodenal horizontal stromal tumors with moderate risk, tumor size was about 7 cm × 7 cm × 5 cm, mitosis had 1/50 high power field, There are curved and dilated blood vessels in submucosa, some of which are congested, which is in accordance with the pathological manifestations of varicose veins, but some of them are blocked by compression. The immunohistochemical results are as follows: Cytokeratin (-), vimentin (+), CD34+, diffuse CD117+ and discovered on gastrointestinal stromal tumor-1 (+), S100-, smooth muscle actin (+), desmin+, caldesmin-, Ki-67 less than 1%. Gene testing found that C-KIT gene Exon-11 had c.1669_1674 deltggag (p.w557_k558del) mutation, while platelet-derived growth factor receptor alpha and related exons had no mutation.