一名53岁的女患者，曾接受克罗恩病治疗约20年，因持续出血便而被送入我们医院。结肠镜检查、计算机断层扫描和磁共振肠道成像显示伊列该患者患有两个回肠狭窄和口侧回肠狭窄周围多个肿大淋巴结。我们随即进行经口双球囊肠镜检查并发现回肠狭窄，有不规则的粘膜表面。基于对狭窄位置进行的病理检查，我们确诊该患者口侧狭窄的病变为小肠腺癌。肛侧狭窄是良性的。我们同时切除了这两个狭窄，并对肿瘤病灶进行了淋巴结清扫术。该癌症病灶的诊断为pStage IIIB，肿瘤蛋白53的免疫组织化学染色呈阳性。克罗恩病患者罹患小肠癌的风险很高，但迄今为止还没有建立监测方案。我们遇到了一例克罗恩病的患者，通过使用气囊辅助肠镜获得术前病理诊断，从而实施了根治手术。本文报告的病例提示了对克罗恩病患者检测到小肠狭窄时进行气囊辅助肠镜检查的重要性。© 2023. 日本胃肠病学会。

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.© 2023. Japanese Society of Gastroenterology.