Objective To evaluate the safety and efficacy of enteroscopy in the treatment of rare small intestinal diseases, including Peutz-Jeghers syndrome (PJS), blue rubber bleb nevus syndrome(BRBNS), and cryptogenic multifocal ulcerative stenosing enteritis (CMUSE), thereby providing a reference for clinical diagnosis and treatment.

Methods Patients with rare small intestinal diseases diagnosed and treated in the Department of Gastroenterology, Shanghai Changhai Hospital, from January 2020 to December 2024 were included. Detailed records of patients′ general information, clinical manifestations, auxiliary examinations, and endoscopic treatment data were collected and systematically analyzed.

Results A total of 30 PJS patients underwent 88 small intestinalpolypectomies under enteroscopy, including 62 procedures via the oral approach (mean operative time: 92.8±30.1 min; largest polyp diameter: 2.9±1.2 cm) and 26 via the anal approach (95.0±29.4 min; 1.9±1.3 cm). Six adverse events occurred in the oral approach group. Ten BRBNS patients received 26 endoscopic treatments (25 sclerosing agent injection under enteroscopy and 1 sclerosing agent injection combined with ligation session), with a mean operative time of 68.1±17.4 min. Eleven intestinal venous aneurysms were ligated, and 4 adverse events were reported. Five CMUSE patients underwent 6 endoscopic treatments (5 samll intestinal stenosis balloon dilations and 1 samll intestinal stenosis incision), with no adverse events observed.

Conclusions Small intestinal endoscopy is feasible, safe, and effective for treating rare small intestinal diseases such as PJS, BRBNS, and CMUSE. For PJS patients, the oral approach should be prioritized. Sclerosing agent injection under enteroscopy for intestinal venous aneurysms in BRBNS via small bowel endoscopy is safe and effective, though the safety of ligation of venous aneurysms under enteroscopy requires further investigation. Stenosis balloon dilation and incision under enteroscopy are both feasible options for CMUSE, and these two approaches can complement each other.