Anorectal fistula is an early manifestation of Crohn's disease that occurs before bowel lesions advance: a study of 11 cases.

The diagnostic significance of single-balloon enteroscopy (SBE) in patients presenting with Crohn's disease (CD)-like anorectal fistula is unknown. We experienced 11 cases undergoing SBE due to CD-like fistulas between December 2007 and April 2013. The mean interval from fistula onset to SBE was 19.2 months with a range of 1.3-44.7. Prior to SBE, all patients underwent anorectal examination under anesthesia (EUA), and 9 patients underwent total colonoscopy with terminal ileal cannulation (TCS-I). One of 7 patients undergoing upper gastrointestinal endoscopy had CD-like gastritis. EUA revealed CD fissures in 7 patients, 1 of whom had no intestinal lesion. Primary TCS-I identified early lesions, such as aphthes and small ulcers, in 4 patients. Among the other 5 patients without any intestinal lesions with TCS-I, SBE indicated early lesions in 3 patients. One of 2 patients who initially underwent SBE without TCS-I showed multiple aphthes. Of the 11 patients, only 4 patients fulfilled the definitive Japanese diagnostic criteria for CD and 7 remained 'suspected CD' cases. Intrinsic anorectal fistulas as a presenting symptom of CD may be an early predictor of bowel lesions. SBE has the potential to reveal incipient disease because an early ileal lesion is not rare for patients with anorectal fistulas.