When Diverticulosis Crosses Boundaries: A Case of Appendiceal Involvement in Colonic Diverticular Disease.

Appendiceal diverticulosis is a rare entity that often mimics acute appendicitis and is typically diagnosed postoperatively. It carries a higher risk of perforation and mortality compared to simple appendicitis, making recognition clinically important. We report a case of a 55-year-old male presenting with a 2-week history of intermittent right iliac fossa pain with acute exacerbation. Imaging demonstrated a distended, thick-walled appendix without clear signs of acute inflammation. The patient underwent a laparoscopic appendectomy for suspected chronic appendicitis. Intraoperative findings showed mild inflammatory changes without perforation. Histopathological examination revealed appendiceal diverticulosis with focal acute diverticulitis. Notably, the patient also had coexisting colonic diverticulosis. The postoperative course was uneventful. Appendiceal diverticulosis is difficult to diagnose preoperatively due to nonspecific clinical and radiologic findings. Histopathology remains the gold standard for diagnosis. This condition is associated with a significantly increased risk of perforation and may coexist with colonic diverticular disease, suggesting a possible shared pathophysiological mechanism. This case highlights the importance of considering appendiceal diverticulosis in atypical or chronic presentations of appendiceal pathology. Routine histopathological evaluation is essential for diagnosis and for identifying potential associations with broader diverticular disease.