Left lower quadrant pain of unusual cause.

The differential diagnosis of left lower quadrant abdominal pain in an adult man includes, among others, sigmoid diverticulitis; leaking abdominal aortic aneurysm; renal colic; epididymitis; incarcerated hernia; bowel obstruction; regional enteritis; psoas abscess; and in this rare instance, situs inversus with acute appendicitis. We report a case of situs inversus totalis with left-sided appendicitis and a brief review of the literature. There were several subtle indicators of total situs inversus present that were missed by the physicians and surgeons who initially evaluated the patient prior to surgery. Computed tomography scan with contrast, however, revealed the diagnosis immediately, and treatment was successfully initiated.