Appendiceal endometrioma mimicking appendiceal neoplasm.

Endometriosis of the vermiform appendix is an uncommon pathology that may present as an appendiceal mass identified on colonoscopy. This may be due to an appendiceal endometrioma or intussusception of the appendix. Mucinous appendiceal neoplasms and neuroendocrine tumors are important clinical differentials. When there is concern for possible malignancy, resection is recommended, usually as a stapled cecectomy. In this case we describe an appendiceal endometrioma presenting as an appendiceal mass, requiring a right hemicolectomy.