Endometriosis of the appendix. Report of twelve cases and review of the literature.

Twelve cases of endometriosis of the vermiform appendix are discribed and reviewed. The incidence of 0.80 per cent is higher than has been previously reported. None of the patients displayed symptoms of acute appendicitis, however, five (42 per cent) patients had symptoms suggestive of chronic or cyclic appendicitis. Laboratory tests were nondiagnostic of this lesion. There did not appear to be a correlation between the histologic location of the endometriosis and the symptoms of chronic or cyclic appendicitis. All cases of endometriosis of the appendix were discovered as a result of incidental appendectomy.