A Large Retroperitoneal Hydatid Cyst: A Cause of Recurrence and What to Consider in Their Management

Retroperitoneal hydatid cyst caused by <i>Echinococcus granulosus</i> is a rare clinical condition that can occur primarily or synchronously with other location. We present a 47-year-old man with a recurrent retroperitoneal echinococcal cyst, complaining of pain in the right lumbar region. The diagnosis was established by ultrasound and computed tomography; additionally a partial cystectomy was performed. Retroperitoneal echinococcal cysts are often initially interpreted as retroperitoneal tumors, except in cases with a history of echinococcosis, which always leaves a degree of doubt regarding the presence of a recurrence or the development of a new cyst. In the present case, the surgical approach was the appropriate choice, followed by antihelminthic therapy. Only the combination of these two approaches can prevent the troublesome complication of echinococcosis recurrence.