Unusual primary locations of hydatid disease. Case report.

Two unusual cases of primary hydatid disease are described. In one of them a retroperitoneal cyst, presenting as a palpable abdominal mass, was strongly adherent to the inferior vena cava and dislocated the right kidney. Partial cystectomy and drainage were performed. The other cyst, of the right ischiorectal fossa, was initially misinterpreted as a perineal of sciatic hernia. It was completely removed. No other site of hydatid disease was found and the patients remain well 3 and 4 years postoperatively.