An unusual cause of acute appendicitis: Appendiceal endometriosis.

Background: While endometriosis is a common disorder in women of reproductive age, appendiceal endometriosis accounts for less than 1% of all pelvic endometriotic lesions. Appendiceal involvement may present as acute appendicitis and definitive diagnosis is made by only postoperative histological examination.

Methods: In this study, we present two cases of female patients who underwent an appendectomy presumed diagnosis as acute appendicitis, and a histopathological examination of the retrieved specimen revealed appendiceal endometriosis.

Conclusions: Endometriosis is defined as the presence of ectopic endometrial tissue outside the lining of the uterine cavity. Gastrointestinal endometriosis is observed in 3-37% of all endometriosis cases, whereas appendiceal endometriosis accounts for only about 3% of gastrointestinal endometriosis. Appendiceal endometriosis is usually asymptomatic, although it sometimes causes abdominal cramps, nausea, chronic pelvic pain, lower gastrointestinal hemorrhage, intussusception, perforation, or acute appendicitis. Conclusions: Appendiceal endometriosis is an unusual histopathological finding. A preoperative diagnosis is difficult, but this condition should be considered when women of childbearing age present with clinical symptoms of acute appendicitis.