Crohn's disease limited to the vermiform appendix.

Thirteen cases of Crohn's disease confined to the vermiform appendix were seen during a 12-year period. They constituted 16.9% of patients with primary resection of the bowel for Crohn's disease in the same period, but only 0.4% of the cases of acute appendicitis. In 10 of the 13 cases there was marked fibrous thickening of the appendiceal wall, and in 11 there were epithelioid cell granulomas. Appendectomy was performed in all cases. None had postoperative fistula or later manifestations of the disease within the observation time averaging 6.3 years. The recurrence rate was previously believed to approach that of recurrence after resection in other parts of the intestines. Collective review of this and three other relatively large case series gave an estimated recurrence rate of 3.5%. We conclude that in Crohn's disease initially confined to the appendix the course appears to be indolent.