Primary Crohn's disease of the colon and rectum.

Crohn's disease of the large bowel has been increasingly recognized and this paper presents a clinical and pathological study of 45 patients in whom the disorder was confined entirely to the large intestine. The clinical and pathological factors are contrasted with those of 86 patients with regional ileitis and of 200 patients with ulcerative colitis. Compared with regional ileitis the disease occurred in an older age group, had a different sex distribution, and a higher incidence of perianal and rectovaginal fistulae. A high incidence of recurrent disease following surgical treatment, found in the patients with regional ileitis, was not found in the patients with primary Crohn's disease of the large intestine. The incidence of the disease relative to ulcerative colitis was approximately 6%. The disease had the same sex distribution as ulcerative colitis but occurred in an older age group. The disease was usually of gradual onset and continuous course, and periods of freedom lasting a month or more were uncommon. The patients came to surgery much earlier than patients with ulcerative colitis.