Granulomatous appendicitis presenting as right lower quadrant pain: CT findings

Background: We present the computed tomographic (CT) findings of granulomatous appendicitis. Methods: Five of 652 (0.9%) patients who had undergone appendectomy for clinically suspected acute appendicitis over a 19-month period proved to have granulomatous appendicitis. One patient had surgery based on a clinical diagnosis of acute appendicitis. Four patients (three men and one woman; age range = 14–39 years) underwent abdominal CT. The CT findings were retrospectively reviewed with special attention to the appendiceal abnormalities. Results: All four patients presented with subacute clinical presentation. Enlarged appendices of 4.5 and 2 cm in diameter with thickened walls of soft tissue density were found in two patients, and periappendicular inflammatory masses were found in the other two. Enlarged mesenteric lymph nodes and right lower quadrant fat stranding was seen in all four patients. Histopathology showed numerous granulomas within the inflamed appendix. Conclusion: Radiologists should be familiar with the rare entity of granulomatous appendicitis in patients examined by CT for suspected acute appendicitis. An insidious clinical presentation with CT findings of an exceptionally large appendix and associated periappendiceal inflammatory changes should raise the possibility of granulomatous appendicitis or carcinoma or lymphoma of the appendix.