Granulomatous disease in the vermiform appendix.

In a twenty-year period 19 appendicectomy specimens were diagnosed as primary Crohn's disease. This represents 4.9% of the total number of both resection specimens and mucosal biopsies diagnosed as Crohn's disease during that time. This is a review of the main histopathological features found in these appendices and their subsequent clinical outcome. The predominant feature is transmural inflammation characterised by fibrosis and giant cell epithelioid granulomata. An accompanying spectrum of acute inflammatory changes is also seen. One patient progressed to more widespread ileal and caecal disease 17 months later. One patient developed perianal fistulae and chronic non-specific proctitis 24 months later. This represents a proven recurrence of one case in a study population of 19. The conclusion is that primary Crohn's disease of the appendix is usually an isolated phenomenon but rarely it may forewarn of more widespread bowel disease in the future. A discussion regarding the differential diagnosis of granulomatous appendiceal lesions is included.