A 66 year old Japanese female was admitted to our department for the examination and treatment of a mass in the cecum. She had experienced no symptoms or signs other than a positive test result for fecal occult blood. The mass in the cecum was confirmed by barium enema, colonofiberscopy and CT scanning. The presumptive diagnosis was a submucosal tumor of the cecum, however, a laparotomy subsequently revealed intussusception of an appendiceal mass. An ileocaecal resection with an ileocolic anastomosis was therefore performed and the mass was histologically diagnosed as a mucocele of the appendix. This patient is only the 24th case of intussusception of a mucocele of the appendix to be reported in Japan. A review of the available literature on this condition follows the case report.