[A Case of Extended Mediastinal and Retroperitoneal Emphysema after Transanal Local Excision of an Early Lower Rectal Adenocarcinoma].

We observed a case of a large collection of mediastinal and retroperitoneal emphysema, which developed after a transanal local excision for an early lower rectal carcinoma and was treated conservatively. An 80's female patient presented with a chief complaint of bowel difficulty, which was diagnosed as mucosal prolapse syndrome with anal sphincter dysfunction. Endoscopic colonoscopy showed full circumferential proliferation of the mucosal membrane including a semicircular protruding lesion, on the upper side of the dentate line.