RESUMO
Mucinous cystadenoma of appendix is a rare clinical entity with very few reported cases in the literature. Consensus on optimal surgical management has not been reached. We report the case of a 65-year-old female patient who presented with fistula over the right iliac fossa. Computed tomography (CT) of the abdomen suggested abscess of the parietal wall. Upon exploration, a mass was found to be arising from the tip of the retroperitoneal appendix and the retroperitoneum was studded with mucoid material. Appendectomy was carried out and final histopathology revealed mucinous cystadenoma with no evidence of malignancy. The patient was discharged uneventfully. The unusual presentation of this disease, as retroperitoneal psuedomyxoma without any intraperitoneal pathology, prompted us to report this case.