Endoscopic characteristics of small intestinal malignant tumors observed by balloon-assisted enteroscopy

BACKGROUND Capsule endoscopy and balloon-assisted enteroscopy (BAE) enable visualization of rare small bowel conditions such as small intestinal malignant tumors. However, details of the endoscopic characteristics of small intestinal malignant tumors are still unknown. AIM To elucidate the endoscopic characteristics of small intestinal malignant tumors. METHODS From March 2005 to February 2017, 1329 BAE procedures were performed at Keio University Hospital. Of these procedures, malignant tumors were classified into three groups, Group 1: epithelial tumors including primary small intestinal cancer, metastatic small intestinal cancer, and direct small intestinal invasion by an adjacent organ cancer; Group 2: small intestinal malignant lymphoma; and Group 3, small intestinal gastrointestinal stromal tumors. We systematically collected clinical and endoscopic data from patients' medical records to determine the endoscopic characteristics for each group. RESULTS The number of patients in each group was 16 (Group 1), 23 (Group 2), and 6 (Group 3), and the percentage of solitary tumors was 100%, 43.5%, and 100%, respectively (P < 0.001). Patients' clinical background parameters including age, symptoms, and laboratory data were not significantly different between the groups. Seventy-five percent of epithelial tumors (Group 1) were located in the upper small intestine (duodenum and ileum), and approximately 70% of gastrointestinal stromal tumors (Group 3) were located in the jejunum. Solitary protruding or mass-type tumors were not seen in malignant lymphoma (Group 2) (P < 0.001). Stenosis was seen more often in Group 1, (68.8%, 27.3%, and 0%; Group 1, 2, and 3, respectively; P = 0.004). Enlarged white villi inside and/or surrounding the tumor were seen in 12.5%, 54.5%, and 0% in Group 1, 2, and 3, respectively (P = 0.001). CONCLUSION The differential diagnosis of small intestinal malignant tumors could be tentatively made based on BAE findings.