A rare but distinctive cause of acute abdomen: appendiceal diverticulitis.

Background: Diverticulosis and diverticulitis of appendix vermiformis is a rare diagnosis. Clinical and laboratory examinations do not show a difference between a progressing diverticulitis and simplex appendicitis. But this entity has a higher mortality rate than common appendicitis.

Objective: This case is presented to illustrate the point that preoperative simple diagnosis of acute appendicitis according to the clinical signs and physical examination may not only be insufficient, but could be fatal in certain circumstances, like appendiceal diverticulitis, if surgical intervention is delayed.

Case Report: Here we present a female patient with a history of right lower abdominal pain and fever of 3 days duration. She was diagnosed with acute appendicitis according to the preoperative physical, laboratory, and imaging examinations. The appendiceal diverticulitis accompanying acute appendicitis was an intraoperative finding, which was proven by histopathologic examination.

Conclusion: It is not easy to document this entity preoperatively. When diagnosed either preoperatively by imaging studies or intraoperatively, the only choice is appendectomy to prevent its serious complications.