Appendicitis as the initial manifestation of Crohn's disease: radiologic features and prognosis.

Twenty-five patients 15-47 years old presented with appendicitis as the initial manifestation of Crohn's disease. This entity accounted for 1.8% of all appendicitis patients undergoing surgery at our institution during a recent 9-year period. Preoperative radiologic studies in 18 (72%) of 25 cases showed abnormalities indicating the presence of appendicitis or periappendiceal abscess, but not the specific diagnosis of Crohn's disease as the underlying cause. Histopathologic evidence for an isolated, transmural, or granulomatous appendicitis was found in 20 patients; in two of these there was a local recurrence within 3 years after surgery, while 18 others have remained asymptomatic during follow-ups of up to 8 years. In the other five patients Crohn's disease caused appendicitis with concurrent inflammation of the cecum or terminal ileum; three of these cases were complicated by progressive granulomatous ileocolitis within 2 years. The data presented herein indicate that Crohn's disease can originate in and be confined to the appendix, yet manifest clinical symptoms leading to emergency laparotomy; preoperative radiologic findings are similar to those of suppurative appendicitis, but visualization of a markedly thickened appendiceal wall with patent or irregularly narrowed lumen supports the diagnosis of Crohn's appendicitis; and primary Crohn's disease of the appendix has a favorable long-term prognosis after simple appendectomy, despite a 10% incidence of recurrence as granulomatous ileocolitis.