Roentgenographic simulation of colonic cancer by benign masses in Crohn's colitis.

Crohn's colitis has recently been shown to predispose the patient to cancer of the colon. Unfortunately, many of the manifestations of colonic malignancy, such as polypoid intraluminal masses and strictures, can be simulated roentgenographically by Crohn's colitis. We present five patients in whom this diagnostic difficulty arose. As established by total or subtotal colectomy, none proved to have malignancy; instead, pronounced transmural inflammation and, in two cases, multiple large pseudopolyps were found to account for the roentgenographically indeterminate lesions. These findings exemplify the difficulty in roentgenographic diagnosis of colonic mass lesions in patients with Chrohn's colitis.