Pathologies of the appendix: a 10-year review of 4670 appendicectomy specimens.

Background: Debate surrounds the management of the macroscopically normal appendix. Current literature recommends its removal given the high incidence of microscopic appendicitis, and other unusual pathologies in the normal-looking appendix. Negative appendicectomies are reported on the decline with increased use of diagnostic radiological adjuncts.

Methods: This study analysed pathologies of the appendix over 10 years in the Pathology Department in Canberra. A positive appendicectomy was defined as acute appendicitis, faecoliths, worms, endometriosis or appendiceal tumours. We reviewed the positive appendicectomy rate over this time period.

Results: There were 4670 appendicectomy specimens in 2386 males (51.1%) and 2284 (49%) females. The incidence of acute appendicitis was 71.3% and the positive appendicectomy rate was 76.3%. There were significantly fewer negative appendicectomies in males (16.8%) compared with females (31.0%). There was no appreciable change in this trend over the study period. Of the positive appendicectomies, there were 129 (3.6%) faecoliths. Of these, only 39.5% had concomitant appendicitis. There were 44 (1.2%) specimens identified with worms. Of these, 40.9% had concomitant appendicitis. There were 14 cases of endometriosis of the appendix of which 36% had concomitant appendicitis. There were 58/3562 (1.6%) appendiceal tumours within the positive appendicectomy group the majority of which were carcinoid tumours (65.5%).

Conclusion: There is a higher incidence of negative appendicectomies in women compared with men, which is similar to other published studies. Faecoliths and worms are a known cause of appendiceal colic and in our series were identified mostly in the absence of histological evidence of appendicitis.