An Unusual Case of Appendiceal Intussusception

Appendiceal intussusception is rare, with an incidence of 0.01% in patients undergoing appendectomy. The invaginated appendix is often misdiagnosed as a polyp or neoplastic lesion; prompting attempted endoscopic resection and complications, such as perforation and peritonitis. Abnormal appendiceal peristalsis in response to a local irritant is hypothesized as the underlying cause. The treatment of choice is surgical resection. We present the unusual case of a 35 year old female, with no past medical history, who was referred for endoscopic removal of a cecal lesion seen on previous colonoscopy. The patient underwent repeat colonoscopy, and a large 4x2 cm semi-pedunculated, smooth, polypoid structure was seen at appendiceal orifice. The lesion was identified as a type five, complete appendiceal intussusception. Surgical resection was performed and pathology was consistent with multifocal endometriosis. Endometriosis is the presence of ectopic endometrial glands and stroma outside of the uterine cavity. It is localized to the appendix in 3-18% of cases, however, the incidence of endometriosis causing appendiceal intussusception is unknown, with few case reports in the literature. Gastroenterologists must recognize appendiceal intussusception on endoscopy and consider this entity in the differential for right lower quadrant pain. Proper diagnosis is imperative to avoid unnecessary procedures and endoscopic complications.1922_A Figure 1. A 4x2 cm large, smooth, semi-pedunculated lesion is seen protruding from the appendiceal orifice on colonoscopy.1922_B Figure 2. A biopsy forcep is used to manipulate and examine the lesion, which is identified as a type five complete appendiceal intussusception.1922_C Figure 3. Surgical specimen of resected invaginated appendix.