Carcinoma in Crohn's disease of the colon

Two cases of carcinoma in Crohn's disease of the colon are reported. One patient was a 30-year-old man who had asymptomatic Crohn's ileocolitis resulting in an acute presentation due to toxic dilatation of the colon. This was preceded by a short prodromal period of four weeks, characterized by intermittent diarrhea on the basis of a coloileal tumor fistula. A mucus-secreting adenocarcinoma was present in the sigmoid colon associated with both adjacent and one nearby focus of high-grade mucosal dysplasia. Pelvic wall and abdominal metastases were present, and the patient died two months later. The other patient was a 60-year-old woman who had a nine-year history of biopsy-proven Crohn's proctocolitis. A stricture of the sigmoid colon due to Crohn's disease also harbored an invasive adenocarcinoma. The carcinoma was not evident preoperatively or on initial gross pathologic examination. The presentation and pathology of large intestinal carcinoma in Crohn's colitis are discussed and illustrated.