Early Detection of Small Bowel Cancer Associated with Crohn's Disease During Routine Postoperative Endoscopic Follow-up: A Case Report

A 48-year-old man with Crohn's disease (CD), who had previously undergone two intestinal surgeries, was referred to our hospital for treatment of perianal lesions. After referral, routine endoscopic follow-up was performed on the remaining colon and the accessible terminal ileum in conjunction with examination under anesthesia (EUA) for the perianal lesions. In the ninth year following referral, dysplastic epithelium was detected in the ileum on the oral side of the anastomosis during EUA and endoscopic assessment. Dysplasia was confirmed again during the third examination after repeated evaluations, leading to ileocecal resection. Histopathological analysis revealed intramucosal adenocarcinoma. Because systematic surveillance for small bowel cancer in CD has not been standardized, this early-stage lesion was detected incidentally during routine postoperative endoscopic follow-up. The patient remained free of both CD recurrence and cancer relapse for 7 years postoperatively.