Thrombosed hemorrhoid mimicking rectal carcinoma at CT.

A 46-year-old man with cirrhosis and portal hypertension complained of lower pelvic pain. CT of the rectum raised a strong suspicion of a rectal tumor. However, rectal examination, anoscopy, direct rectoscopy, and, unfortunately, post-mortem dissection, failed to confirm its existence. Nevertheless, large flat hemorrhoids were evident. Review of the patient's chart disclosed the presence of large thrombosed hemorrhoids detected by rectal examination prior to the CT examination. It is suggested that rectal hemorrhoids be included in the differential diagnosis of rectal tumor shown by CT in patients with portal hypertension.