[Carcinoma complicating ulcerative colitis. Analysis of 8 Japanese cases].

Eight patients with ulcerative colitis complicated by carcinoma were investigated histopathologically on their resected colorectal specimens. Four patients carried multiple tumors, another four patients a solitary tumor. The age at the onset of the colitis in patients with multiple carcinoma was younger in average (27 years old) than that in the patients with a solitary carcinoma (45 years old). Duration of the disease before surgery exceeded 10 years in six of the eight patients. A total of eight tumors of 10 mm or more in dimension were found in four multiple cases, six of them being located in the rectum. These tumors presented peculiar macroscopic features, such as villous, putty-like, nodular, or flat, and were advanced histopathologically, well or moderately differentiated adenocarcinomas in most cases. Six of the eight accompanied areas of epithelial dysplasia adjacent to the carcinoma, the border between carcinoma and dysplasia being vague in three of the six. All multiple cases showed active changes of ulcerative colitis or chronic inflammatory processes such as thickening of the muscularis mucosa, submucosal fibrosis and Paneth cell metaplasia in the crypts. Furthermore, all multiple cases had minute adenocarcinomas, less than 10 mm in diameter, the tumor being restricted to the mucosa or to the mucosa and submucosa. Four of the nine minute carcinomas coexisted with epithelial dysplasia, suggesting that carcinoma developed from dysplasia. On the contrary, the remaining carcinomas carried no dysplasic area with a possibility that carcinoma developed also from nondysplastic atrophic mucosa. Three of the four solitary tumors were conventional adenocarcinomas associated with chronic inflammatory or dysplastic change in the bowel. The specific stainings by lectins and high-iron-diamine (HID) gave no appreciable help in diagnosing the epithelial dysplasia because of unsettled staining results. A large number of argyrophil cells were present in dysplastic epithelia, although the number of such cells was small in carcinomas.