Adenocarcinoma of the rectum with various grades of atypia in association with Crohn's disease: a case report and immunohistochemistry of p53 and Ki-67.

A case of adenocarcinoma of the rectum in a 41-year-old woman, in association with Crohn's disease is presented. The patient had suffered diarrhea and constipation, and Crohn's disease was suspected. Although the endoscopy did not reveal the presence of any tumors, biopsy specimens demonstrated adenocarcinoma. A Miles' operation was performed. The adenocarcinoma was composed of various grades of atypia and had invaded the non-peritonealized perirectal tissues. The infiltration of lymphocytes and plasma cells was moderate at the perimeter of the carcinoma and mild in the distant regions. Epithelioid cell granulomas were found. The p53 labeling index (LI) increased with the grade of atypia over the entire length of the carcinomatous gland. In carcinomas with high grade atypia, the p53 LI was high in both the upper and the lower halves of the gland. In carcinomas with low or moderate grade atypia however, the p53 LI was high in the lower half and low in the upper half of the gland. The Ki-67 LI over the entire gland was higher in carcinomas with high grade atypia than in carcinomas with low or moderate grade atypia.