Microdiverticula and submucosal epithelial elements in ulcerative and granulomatous diseases of the ileum and colon.

A case of granulomatous ileocolitis which also showed features of ulcerative colitis, and in which lesions were believed to be due to inflammation of previously undescribed structures, microdiverticula, was reported previously. Subsequently, sections of the segments of bowel received from 17 cases of regional enteritis and 16 cases of ulcerative colitis were re-examined for the presence of similar microdiverticula and submucosal epithelial elements. The same structures were present in five cases of regional enteritis and in 14 of ulcerative colitis. A granulomatous type of inflammatory response was found in the bowel and lymph nodes in 14 of the 17 cases of regional enteritis, and in none of the cases labelled ulcerative colitis. In spite of this, difficulty was experienced in placing some cases in one or other diagnostic category. This re-emphasizes the possibility that the two conditions may not be etiologically discrete, and that both may be, in fact, related to the presence of microdiverticula. In addition, it may be that colitis cystica profunda is a result of microdiverticulosis in which the submucosal glandular structures attain unusually large proportions.