Anal lesions complicating Crohn's disease.

Anal lesions were registered in 19 of 72 patients (26%) operated on for Crohn's disease at the Tampere University Hospital during 1966-1988. During a median follow-up time of six years two patients with anal disease (10%) needed no therapy, while 11 (58%) required only minimal surgery: drainage of an anal abscess in six, anal fistulotomy in three and anal dilatation in two patients, four (21%) had proctectomy for anal disease and one had a resection of active proximal disease. One patient had fecal diversion to control anal disease with poor results. There was one anorectal carcinoma which developed into prolonged anorectal stenosis. One of 10 patients (10%) with proximal disease in the small bowel needed proctectomy for anal disease while three of seven (43%) with proximal disease in the large bowel had proctectomy. On re-examination of all 72 patients with Crohn's disease there were 11 new cases with anal symptoms after a median follow-up of 12 years (eight cases with skin tags and three with anal stenosis); these patients have not required surgery. The study shows that the natural course of anal lesions in Crohn's patients varies widely and only 21% have severe anorectal disease. One patient developed anorectal carcinoma which points to the need of regular follow-up of anorectal stenosis.