[An extremely rare retro-vesico-prostatic tumor: peritoneal cystic mesothelioma].

The authors report an uncommon case of sub-peritoneal tumor. This tumor, which took the econographic features of multivesicular hydatic cyst, was in fact a mesothelia of the peritoneum. It was located behind the bladder and the prostate. The authors think that this localisation is an argument in favor of the peritoneal origin of Denonvilliers's prostatoperitoneal fascia.