Retrospective study of 24 cases of acute appendiceal diverticulitis: CT findings and pathological correlations.

PURPOSE: Appendiceal diverticulitis is relatively rare and is difficult to distinguish clinically and radiologically from acute appendicitis. The aim of this study was to describe the computed tomography (CT) findings of acute appendiceal diverticulitis. MATERIALS AND METHODS: Among the 1329 patients who underwent appendectomy at our institution between January 2010 and July 2015, 28 were diagnosed pathologically with appendiceal diverticulitis, including 24 patients who were evaluated by preoperative CT. The control group consisted of 38 patients without diverticulitis. Average age of patients, ratio of males to females, appendiceal diameter, presence of a diverticulum, diverticular enhancement, peri-appendiceal fat stranding, peri-appendiceal loculated fluid and perforation, and the presence of appendicolith were evaluated retrospectively. RESULTS: Peri-appendiceal fat stranding (p < 0.005), appendiceal diameter (p < 0.005), and peri-appendiceal loculated fluid differed significantly between the diverticulitis and non-diverticulitis groups (p < 0.005). CONCLUSION: Although relatively uncommon, appendiceal diverticulitis should be included in the differential diagnosis of acute appendicitis. It differs from typical acute appendicitis by the presence of an inflamed diverticulum, seen on CT. These patients are also more likely to have peri-appendiceal extra-luminal loculated fluid, peri-appendiceal fat stranding, and a larger diameter of the appendix. The latter finding is likely due to the increased intraluminal pressure.