Appendiceal diverticulitis presenting as acute appendicitis diagnosed postoperatively

Abstract Appendiceal diverticular disease is a rare entity. We report a case of appendiceal diverticulitis mimicking acute appendicitis and diagnosed postoperatively on histopathology. A 28-year-old female presented with a 2-day history of shifting periumbilical pain associated with nausea and anorexia. A computed tomography scan of the abdomen demonstrated acute appendicitis. She was taken to laparoscopic appendectomy. Histopathology showed appendiceal diverticulitis, and perforation of an inflamed diverticulum with periappendicitis. Diverticulosis of the appendix is classified as congenital and acquired. Diagnosis can be made preoperatively by imaging. In this case, diverticulosis was not radiologically evident, and was interpreted as acute appendicitis. Gross appearance of the resected appendix was not suggestive of diverticulitis. Other cases reported that the gross specimen had evidence of diverticular disease. Surgeons should be aware that inflamed appendixes may harbor different pathologies warranting further management.