[Appendiceal mucocele disclosed by a psoas tumor. Apropos of a case].

Mucocele of the appendix is a rare lesion. Rupture of appendicular mucocele into the psoas is uncommon. We report a case of a 77-year-old man, with psoas tumor on abdominopelvic ultrasonography and computed tomography. The preoperative diagnosis was type III hydatid cyst of the psoas, psoas tumor or retroperitoneal mass. Surgical exploration revealed an appendicular mucocele ruptured into the psoas. Appendicectomy was performed with an uneventful postoperative course after 3 years. The authors discuss the diagnostic and therapeutic problems raised by this rare lesion.