"The evolution of the solitary ulcer of the rectum"--an endoscopic and histopathological study.

A follow-up study of fourteen out of twenty-seven cases of solitary ulcer syndrome of the rectum was performed at one year's interval from the previous endoscopic and histologic examination. Most of the lesions consistently changed their aspect, resulting in incomplete irregular narrowings, polypoid protrusions or linear ulcers. The symptoms remained unchanged or slightly diminished. A striking difference was found in the histological pattern of the "evolved" ulcer in comparison to the active one, the former showing features of hyperplastic (metaplastic) colonic polyps as well as of the so called "transitional mucosa". It is suggested that chronic ischemia occurring in solitary ulcer of the rectum leads to "transitional mucosa" as an exaggerated regenerative phenomenon, hyperplastic (metaplastic) mucosa representing a later maturative phase. Possibly "transitional" mucosa may undergo dysplastic changes under the influence of environmental factors.