Figure 4a. Tubulovillous adenoma. (a) Endoluminal 3D view from CT colonography shows a 10-mm pedunculated polyp with a well-defined stalk. (b) Axial 2D view shows the same pedunculated polyp (arrowhead). Unlike most other pedunculated lesions, which are more easily recognized as such on 3D views, the stalk and polyp in this case happen to be aligned in a standard 2D plane.