Appendicitis with perforation: the dilated transverse colon sign.

The dilated transverse colon sign in acute appendicitis has not been described previously. However, it was noted in 10 of 82 patients with acute appendicitis, and in all 10 cases, perforation had occurred. Since this sign was not seen in nonperforated appendicitis, it is believed to be one of the earliest, if not the earliest, radiographic signs of perforation. It is believed to result from a combination of paralytic ileus of the transverse colon and spasm of the ascending colon, and once appreciated, becomes a valuable asset in the plain film assessment of appendicitis.