Small bowel cancer in a patient with Crohn's disease diagnosed preoperatively by double-balloon enteroscopy

A 53-year-old female patient, who had been treated for Crohn's disease for approximately 20 years, was admitted to our hospital with a chief complaint of persistent bloody stools. Colonoscopy, computed tomography, and magnetic resonance enterography revealed two stenoses of the ileum and multiple enlarged lymph nodes around the oral-side ileal stenosis. We accordingly performed transoral double-balloon enteroscopy and found ileal stenosis with an irregular mucosal surface. Based on pathological examination of the stenosis, adenocarcinoma of the small bowel was diagnosed for the oral-side stenosis. The stenosis on the anal side was benign. The two stenoses were resected simultaneously, and lymph node dissection was performed on the cancerous lesion. The diagnosis of the cancerous lesion was pStage IIIB, and immunohistochemical staining was positive for tumor protein 53. Patients with Crohn's disease are at a high risk of small bowel cancer, but no surveillance protocol has been established to date. We encountered a case of Crohn's disease in which radical surgery was possible, owing to preoperative pathological diagnosis, by using balloon-assisted enteroscopy. In this paper, we report a case that suggests the importance of performing balloon-assisted enteroscopy when small bowel stenosis is detected in patients with Crohn's disease.