Primary Retroperitoneal Hydatid Cyst in a Pediatric Patient: A Report of a Rare Case

Hydatid disease is a parasitic infection caused by the larval stage of Echinococcus granulosus; it can involve any organ. Retroperitoneal localization is exceptionally rare and often presents with nonspecific symptoms, which may delay diagnosis and mimic other retroperitoneal cystic masses. Therefore, in endemic settings, hydatid disease should be considered in the differential diagnosis of any retroperitoneal mass. We report a 13-year-old boy who presented with an isolated, painless right flank mass. Non-contrast abdominal CT showed a well-defined, right subhepatic retroperitoneal cystic. The patient underwent complete surgical excision via an extraperitoneal lumbotomy. This case highlights the importance of maintaining clinical suspicion for hydatid disease when evaluating retroperitoneal cystic masses in endemic areas and supports careful surgical management to prevent intraoperative dissemination.