Appendiceal Endometriosis Presenting as Possible Cecal Mass.

Background: Endometriosis is endometrial tissue located outside of the uterus. Endometriosis is rarely found in the appendix and can present very similar to acute appendicitis and is often indistinguishable on physical exam and imaging. The diagnosis is typically made after an appendectomy on pathology.

Case Summary: A 45-year-old female presented with right sided abdominal pain and CT revealed a possible cecal or appendiceal lesion. Colonoscopy revealed a submucosal non-obstructing cecal mass. In the operating room, the appendix was completely adherent to the cecum and a laparoscopic ileocecectomy was performed. Pathology revealed endometriosis of the appendix and cecum.

Discussion: Endometriosis of the appendix is a rare condition reported in less than 1% of females that is diagnosed after an appendectomy is performed for suspected appendicitis or other pathology. This diagnosis is made based on the finding of endometrial glands and stroma in the appendix. This can present as acute appendicitis or appendiceal or peri-appendiceal mass on imaging. When symptomatic, pain can align with the menstrual cycle and hemoperitoneum may be encountered intra-operatively. Treatment can be appendectomy, ileocecectomy, or right hemicolectomy if malignancy is suspected. In the patient we described, an ileocecectomy was performed with the intention of converting to a right hemicolectomy if the frozen section pathology had revealed malignancy. This case illustrates the importance of having a broad differential when diagnosing patients with abdominal pain, especially in women of childbearing age.

Conclusion: Appendiceal endometriosis should be considered in females of childbearing age with abdominal pain or cecal/appendiceal mass on imaging.