Because the complication seemed to be uncommon, we have reviewed our experience with carcinoma complicating ulcerative colitis. Between 1934 and 1943 one of us saw 2 cases of carcinoma in 336 cases of ulcerative colitis. This was an incidence of 0.59 per cent. During the same period 1608 cases of carcinoma of the colon were seen at the Cleveland Clinic.
Because both patients herein reported were under 30 years of age, our attention was directed to this age group. One per cent (17 cases) of all cases of carcinoma of the colon and 38 per cent (128 cases) of all cases of ulcerative colitis occurred in persons under 30. In this same age group the incidence of carcinoma of the colon with chronic ulcerative colitis (1.5 per cent) was slightly higher than the incidence without ulcerative colitis (1 per cent).
Ewing1 considered it significant that carcinoma rarely occurred in ulcerative colitis. Matzner and Schaefer2 reported 1 case of carcinoma complicating ulcerative colitis. The patient was a 29 year old man. Yeomans3 reported 7 cases of malignant neoplasm developing in rectal adenoma, 1 of which occurred with ulcerative colitis. This patient was a 33 year old woman. Hurst4 stated that an adenomatous polyp might become malignant and that carcinoma might complicate ulcerative colitis, but that most malignant adenomas were not secondary to or associated with colitis. Swinton and Warren5 stated that they had not observed progression of polypoid changes in ulcerative colitis to malignant disease. On the other hand, Ganshorn6 demonstrated. . .