Figure 11d. Familial adenomatous polyposis syndrome with adenocarcinoma. (a) Contrast-enhanced 2D axial CT image shows a large irregular soft-tissue mass in the ascending colon (arrowheads). The CT study was performed as a routine examination without colonic preparation. (b) Digital photograph from subsequent optical colonoscopy shows the large mass seen in a, which proved to be malignant at histologic evaluation. (c) Axial CT image obtained caudad to a shows additional smaller polypoid lesions (arrowheads), which might be difficult to distinguish from stool on this CT scan obtained without colonic cleansing. (d) Digital photograph from optical colonoscopy shows multiple polyps in the transverse colon.