The bowler hat: a valid sign of colonic polyps?

This report briefly describes several cases of diverticula simulating colonic mucosal lesions. We have found that the bowler hat configuration, in particular, frequently occurs in the presence of diverticular disease. In our series, no polyp was found to exhibit the bowler hat sign, while 12 cases of diverticular disease displayed 1 or more "bowler hats." Differentiation between polyps and diverticula displaying the bowler hat sign may be possible, but we conclude that the bowler hat sign per se is a nonspecific finding and that additional views may be necessary to confirm the presence of polyps.