Primary adenocarcinoma of appendix, colonic type associated with perforating peritonitis in an elderly patient

We report a case of colonic type adenocarcinoma of the appendix with perforating peritonitis in a 92-year-old man. The preoperative diagnosis was localized peritonitis due to acute appendicitis and emergency laparotomy was performed. A gray, hard tumor was palpated at the base of the appendix. Appendiceal cancer was suspected, and right hemicolectomy was performed. The histopathological diagnosis was moderately differentiated adenocarcinoma of the appendix. The tumor obstructed the orifice of the appendix, and this may have caused the perforation of the appendix. The patient had an uneventful postoperative course and there have been no signs of recurrence in the 2 years since the operation.