Appendiceal inversion secondary to endometriosis and dilated mucinous adenoma identified on screening colonoscopy

Appendix intussusception (AI), with ~200 reported cases, is a rare condition in which the appendix invaginates into the cecum [1]. Etiologies include benign and malignant pathologies including both intraluminal and extraluminal lesions, but dual pathology has not been described previously. We present a case of a 52-year-old female with colonoscopic findings suspicious for AI or a submucosal lesion. Surgical pathology following appendectomy revealed AI caused by both endometriosis and a mucinous adenoma. AI is usually diagnosed incidentally on laparoscopy. Though rarely diagnosed preoperatively, recognizing AI on colonoscopy is critical. To our knowledge, this is the first reported case of AI due to both endometriosis and mucinous neoplasm.