[Retrovesical hydatid cyst. Apropos of 2 cases]

A hypogastric mass compressing the bladder in an adult, in a zone endemic for hydatid disease, should raise to suspicion of a retrovesical cyst, especially as the cyst sometimes opens into the bladder resulting in haematuria and hydatiduria. Intravenous urography and ultrasonography facilitate the topographical diagnosis. Treatment is surgical: transperitoneal cystectomy and pericystic resection as extensive as possible with exploration of the abdomen looking for other sites (liver, mesentery, omentum). This treatment was successful in the two cases reported here. In conclusion, a stable cure can be obtained by adopting a well defined therapeutic approach to these rare lesions.