US and CT diagnosis of complete cecocolic intussusception caused by an appendiceal mucocele

Appendiceal mucoceles are found in only 0.2-0.3% of all appendectomy materials. Colocolic intussusception of the appendix is also very uncommon. We report the very rare association of these two entities in a 40-year-old patient presenting with intermittent right abdominal pain accompanied by a palpable mass in the right flank. The full diagnosis was made pre-operatively by ultrasound and confirmed by helical CT by means of unequivocal signs of intussusception associated with a very suggestive "cup-and-ball" aspect of the mucocele induced by a global mucinous cystadenoma of the appendix. A brief review of the available literature on mucocele is given.