Case report of primary retroperitoneal hydatid cyst.

Hydatid cyst develops in retroperitoneal space without accompanied lesion in other organs is defined as primary retroperitoneal hydatid cyst. It is extremely rare though hydatid cyst may affect every organ in human body. A 15 years old boy presented with a giant retroperitoneal cyst and hydatid cyst was suspected. Thorough examination did not revealed lesions in liver, lung, kidney or other organs. The diagnosis was confirmed through laparotomy. The diagnosis is difficult, but the possibility should be considered before operation to prevent spillage or fatal anaphylactic shock. Living in an endemic area, ultrasonography, CT or serology test is helpful in the diagnosis of this disease. Total cystectomy is the ideal surgery, if not possible or at high risk, partial pericystectomy is acceptable.