Herniation of mucosal epithelium into the submucosa in chronic ulcerative colitis.

Herniation of the glandular epithelium into the submucosa has been observed in 11 out of 27 cases of chronic ulcerative colitis. Glandular herniation was associated with thickening of the muscularis mucosae, with interruption of the muscularis mucosae by lymphoid follicles, and, in five of the 11 cases, with significant crowding of the glands of the mucosa. This study strongly suggests that sustained contraction of the muscularis mucosae, which has been shown by others to be a major feature of chronic ulcerative colitis, is the prime factor in the formation of downgrowths or herniations of the glandular epithelium into the submucosa. Comparison of the cases in which cancer developed with those where there was glandular herniation led to the conclusion that they are independent associations of chronic ulcerative colitis, and that glandular herniation plays no part in the development of dysplasia or cancer.