Over 60% of small intestinal tumors are found in the duodenum, and the most frequent malignancies of the duodenum include GISTs, neuroendocrine neoplasm, adenocarcinoma, lymphoma, sarcoma, teratoma, and secondary metastases . GISTs is the most common submucosal tumours of gastrointestinal tract, which originate from connective tissue, muscle, lymphoid tissue, adipose tissue, nerves and blood vessels located below the submucosa . GISTs can be probably classified as unfavourable prognosis when they are more than 5 cm, occuring tumor rupture and the mitotic rate is more than 5 mitoses per 50 high-power fields . Study has shown that adequate endoscopic treatment strategies of GISTs could lead to favorable outcomes and good prognosis . ESD has been established as a curable safe procedure for the treatment of tumours on the surface of the stomach, esophagus, and colon, while most endoscopic strategies for the resection of duodenal tumours remain undefined . With the rapid development and continuous maturity of endoscopic therapy, the incidence of complications have received widespread attention during the perioperative period. The complications of ESD include bleeding, perforation (about 30%), and pancreatitis [10-11]. Shi et al.  reported a novel “endoscopic interrupted suture——purse-string suture”, which combined the traditional nylon rope and titanium clips for closure of operative wound, and was widely used to repair iatrogenic perforation or active perforation during ESD. In our case, the patient with recurrent upper gastrointestinal bleeding followed a comprehensive examination, so the diagnosis of stromal tumor in descending duodenum with bleeding was considered. ESD or abdominal surgery was selected as the operative method, ESD was performed in accordance with the wishes of the patient after full communication with the patient in the end. It is necessary to evaluate the depth of tumors infiltration by endoscopic ultrasonography and CT before ESD, because 30% to 40% of GISTs grow outwards, 29% to 44% of GISTs in intramural growth, 18% to 22% in endoluminal growth, 16% to 20% in mixed growth . The preoperative CT indicated that the tumor body was significantly outward from the lumen, and thus iatrogenic perforation could be foreseeable during ESD. Therefore, we already communicated adequately with the patient about the possible complications and prognosis before ESD. Not surprisingly, the postoperative pathology confirmed the diagnosis of descending duodenal stromal tumor. We applied improved purse-string suture technique to close perforated wound of descending duodenum, but there were few reports about it in the world. Unfortunately, follow-up to 1 month suggested that delayed perforation and abdominal infection occurred. This may be related to the personal factors and immature purse-string suture technique, which was rarely used in the duodenum. Besides, the risk of complications with ESD resection of nonampullary duodenal tumours is higher compared to tumours in other digestive tracts because of thinner intestinal wall and existence of duodenal fluid containing abundant digestive enzymes. Especially in the posterior wall of duodenum, the gas may pass through the exposed thin muscularis propria into the retroperitoneum during treatment, even if there is no obvious sign of perforation . On the other hand, because the position of the descending duodenum is relatively fixed, it is difficult to gather relatively fixed mucosa together, and even if the wound is successfully closed by titanium clips, its effect is not as obvious as that of other parts of gastrointestinal tract . But it did not significantly affect the prognosis of the patient. The remedial treatment of duodenal fistula after closure of ESD-related perforation is still unclear. Because the lesion which gave rise to serious retroperitoneal abscess was located in the descending duodenum, gastrointestinal surgeon and hepatobiliary surgeon considered that surgical treatment was very difficult and risky. After multidisciplinary discussions, We determined to carry through a series of treatments mentioned in the case presentation. Thereinto, it is very necessary to place abscess drainage tube under the guidance of CT, which can obviously relieve the systemic and local symptoms caused by pus. Finally, all the symptoms improved markedly. Follow-up was done for 6 months without recurrence.
Although there were few reports about the application of ESD and purse-string suture for stromal tumors in descending duodenum, they are a promising mean of minimally invasive treatment. Endoscopic therapies effectively could avoid most traditional surgical procedures, relieve the suffering of the patients, shorten hospital stay, and improve the medical therapy efficiency. There are some experiences that are summarized as follows: (1) Preoperative CT and endoscopic ultrasonography can help us to preliminarily understand the depth of tumor invasion and provide a reference for the depth of resection during the operation. (2) Intraoperative perforation is a common complication of ESD for treatment of duodenal lesions. So, we recommend experienced doctors to manage ESD. More attention should be paid to the purse-string suture of the perforated wound. (3) Due to the abundant blood supply of the duodenum, intraoperative and postoperative hemorrhage are more possible to happen, although it did not occur in this patient. After endoscopic resection, the exposed blood vessels of the wound should be carefully searched and coagulated. (4) Observing postoperative complications closely, such as bleeding, perforation, fever, and pancreatitis. (5) If serious complications occur, multidisciplinary discussions should be conducted for further treatment.