Figure 11a. Colon adenocarcinoma. (a) Axial contrast-enhanced CT image of another patient shows wall thickening (arrows) of the descending colon that is disproportionately greater than the degree of fat stranding (arrowhead). (b) Axial contrast-enhanced CT image obtained at a lower level shows the abrupt transition from thick to normal wall ("shouldering") (short arrow) and the presence of lymphadenopathy (long arrow). Enlarged regional lymph nodes are more suggestive of colon cancer than of diverticulitis.