[Isolated retrovesical and retroperitoneal hydatid cysts. 5 case reports].

In the light of five cases of isolated retrovesical and retroperitoneal hydatid cysts, the characteristics of these rare locations are reviewed and the hypotheses of pathogenesis are discussed. An abdominal or abdomino-pelvic mass is the most frequent sign. Ultrasonography and computed tomography are valuable in the diagnosis of these lesions. Partial cysto-pericystectomy via an extraperitoneal approach is the treatment of choice for these hydatid cysts.