Small bowel carcinoma in Crohn's disease. Distinguishing features and risk factors.

An 86-year-old woman who developed small bowel adenocarcinoma 40 years following in-continuity bypass of a 60-cm segment of regional ileitis represents the 22nd reported patient with this complication of bypassed Crohn's disease. Her case demonstrates several of the typical clinical features of such cancers: late recrudescence of disease following a 40-year period of relative quiescence; delayed diagnosis due to misinterpretation of the clinical picture (intestinal obstruction, abdominal mass, intraabdominal abscess, and fistula formation) as due to inflammatory bowel disease; and an exceedingly poor prognosis with rapid widespread local dissemination and death. Histologically, severe dysplasia was demonstrated both in close proximity to and at a distance from the lesion. The increasing number of case reports of adenocarcinoma arising at the site of long-standing Crohn's disease, many with dysplasia within areas of diseased bowel, is further evidence that Crohn's disease is a precancerous condition. Physicians must continue to search for methods of earlier diagnosis to improve the prognosis of small bowel carcinoma in Crohn's disease.