This is a case of acute appendicitis complicated by perforation, manifested by a large inflammatory appendicular mass/phlegmon in the right iliac fossa, adherent to an adjacent ileal loop, resulting in reactive ileal wall thickening and edema with secondary small-bowel obstruction due to ileus.

Acute appendicitis may result in small bowel obstruction, which may be mechanical SBO due to localized periappendiceal inflammation resulting in adhesions, or as a result of ileus secondary to localized peritonitis with reactive bowel wall inflammation due to a perforated appendix.

If acute appendicitis and small bowel obstruction coexist, symptoms of SBO may mask those of acute appendicitis.