A case of adenocarcinoma of the small intestine in a Japanese patient withCrohn disease: A report with immunohistochemical and oncogenic analyses

We report a rare case of Crohn disease accompanied by a small-bowel carcino ma that developed in a 54-year-old Japanese man. The ulcerating tumor, whic h histologically proved to be a poorly differentiated adenocarcinoma and dy splasia surrounding the carcinoma, was located in the diseased ileum. The K i-67 immunoreactive epithelial cells were increased in regenerative mucosa as compared with values for normal mucose. The Ki-67- and p53-positive cell s were increased in dysplasia and carcinoma as compared with values for reg enerative or normal mucosa. In contrast, the p21(WAF1/CIP1) immunoreactive cells were decreased in this order. Intense DCC (deleted in colorectal canc er) expression was constantly shown among normal, regenerative, dysplastic and cancerous tissues. No bcl-2 expression and c-ai-ms mutations were appar ent. In conclusion, enhanced epithelial cell proliferation p53 overexpressi on, and decrease of p21(WAF1/CIP1) expression may predispose the small-bowe l mucosa to dysplasia and carcinoma development in Crohn disease.