Ascending retrocecal appendicitis: clinical and computed tomographic findings.

To describe the clinical presentation and computed tomographic (CT) features of ascending retrocecal appendicitis. During the past 8 years, 1670 patients with surgically proven appendicitis were identified by a retrospective investigation. Thirty-three patients who underwent contrast-enhanced abdominal CT before surgery and had ascending retrocecal appendicitis at surgery were included in the patient cohort. The clinical and CT findings of these 33 patients were analyzed. Patients presented with right lower abdominal pain (49%, 16/33), right flank pain (24%, 8/33), right upper abdominal pain (18%, 6/33), and periumbilical pain (15%, 5/33). Inflamed ascending retrocecal appendices were visualized completely in 70% (23/33), partially in 21% (7 of 33), and not detected in the remaining 9% (3/33). Periappendiceal inflammatory changes were most commonly observed in the retrocolic space in 88% (29/33), followed by paracolic gutter (30%, 10/33), pararenal space (27%, 9/33), mesentery (24%, 8/33), perirenal space (18%, 6/33), and subhepatic space (3%, 1/33). Inflammatory thickening of Gerota fascia (70%, 23/33) and the lateroconal fascia (64%, 21/33) was observed as well. Perforation of the appendix with the formation of an abscess was present in 49% (16/33). The abscesses were most commonly located in the retrocolic space (88%, 14/16). Diffuse wall thickenings of the cecum (67%, 22/33) and the ascending colon (64%, 21/33) were often observed also. Appendicoliths were found in 33% (11/33). More than half of patients with ascending retrocecal appendicitis presented with atypical clinical presentation. At CT, ascending retrocecal appendicitis was associated with a high incidence of retroperitoneal inflammatory changes and appendiceal perforation.