A Case of Abdominal Wall Abscess Due to a Perforated Appendiceal Diverticulum with Neuroendocrine Tumor

Abstract

　　A 63-year-old man presented with a one-month history of right lower abdominal pain. He had a fever. Physical examination showed a 15-cm immobile mass in the right lower quadrant with redness and tenderness, but without rebound or guarding. Computed tomography showed an abdominal wall abscess in contact with the body of the appendix. We surmised that the abscess had formed due to appendicitis. Percutaneous drainage was performed. However, the right lower abdominal pain and inflammation of the appendix persisted, so, we performed an appendectomy. We found the omentum and terminal ileum were adhered to the abdominal wall, and the body of the appendix was adhered to the abdominal wall in the omentum. A fistula between the abdominal wall abscess and the body of the appendix was suggested. On histopathology, a pseudo-diverticulum and evidence of a confined neuroendocrine tumor lesion around the diverticulum were found. An abdominal wall abscess formation due to perforated appendiceal diverticulum was diagnosed. An abdominal wall abscess is extremely rare. Also, we review the literature about the association between appendiceal diverticulum and appendiceal neoplasm.