Crohn's disease isolated to the appendix: truths and fallacies.

Twenty-five cases of Crohn's disease confined to the appendix were reported in eight hospitals in Israel during a 15-year period. Review of the histologic slides confirmed the diagnosis in 22 cases. Re-evaluation of these 22 patients included physical examination and radiologic studies of the small and large bowel. Rectosigmoidoscopy was performed in 16 patients. Signs and symptoms of Crohn's disease at other sites in the gastrointestinal tract did not occur during follow-up periods of two to 15 years (mean, 6.4 years) after appendectomy. This study and a review of the literature indicate that in most cases (93 per cent) Crohn's disease initially limited to the appendix is not a predictor of subsequent involvement of another portion of the bowel. It is concluded that the so-called Crohn's disease isolated to the appendix is a form of chronic granulomatous and follicular appendicitis of unknown etiology that is unrelated nosologically in the majority of the cases to Crohn's disease proper.