Malformation of the Vermiform Appendix Originating from the Ascending Colon

Abstract

A 12-year-old boy was referred to our hospital with nausea and epigastralgia. Enhanced computed tomography (CT) showed a swollen appendix with a large fecal stone and a moderate amount of ascites. He was diagnosed with gangrenous appendicitis with local peritonitis and underwent an emergency appendectomy. On examining the vermiform appendix, the root was found to originate from the posterolateral side of the ascending colon, which was the anal side of the connection to the terminal ileum. The mesoappendix was resected, and the vermiform appendix was removed. No appendix-like protrusion was found at the end of the cecum. Pathological examination of the resected specimen confirmed the vermiform appendix, which had rich lymphoid follicles at the wall, and it was diagnosed as gangrenous appendicitis. A malformation of the appendix is quite rare. A few cases of agenesis of the appendix or double appendix have been reported, but no case of the appendix originating from the large intestine other than the cecum has been reported in Japan, while only three cases have been reported worldwide. A rare case is presented along with some discussion.