Endometriosis of the vermiform appendix as an exceptional cause of acute perforated appendicitis during pregnancy.

The incidence of appendicitis presenting during pregnancy is less than 1 in 1500. Most cases of endometriosis of the appendix are discovered as a result of incidental appendectomy. True perforated appendicitis in an endometriotic area has not been reported before. The authors report the case of a 28-year-old woman in her 27th week of pregnancy who underwent an appendicectomy for inflamed, perforated appendix with transmural endometriosis and accompanying decidual reaction.