Endoscopic removal of an intussuscepted appendix mimicking a polyp--an endoscopic hazard.

A 55-yr-old white woman with a polypoid filling defect in the caput cecum, on barium enema examination, had endoscopic removal of this mass. This was immediately recognized macroscopically to be an intussuscepted appendix. This case is only the second naturally inverting appendix to be removed endoscopically, and it was complicated 18 h later by local peritonitis which was heralded by acute right lower quadrant pain. Laparotomy revealed a cleanly transected base of appendix and cecal adhesions representing previous chronic inflammatory disease. Endoscopists should consider this diagnosis in all cases of mass lesions of the caput cecum. It is imperative to retrieve such lesions if polypectomy is performed, as the macroscopic diagnosis is then evident. Once the diagnosis is established, immediate surgery is advised rather than watchful waiting.