Reporting a single case of cystic echinococcosis in retroperitoneal mass of uncertain origin.

Echinococcal disease (hydatid disease (HD) is an endemic parasitosis caused by Echinococcus granulosus in the larval stage, and it is typically due to the production of unilocular cystic lesions, usually involving the liver for the majority of patients and the lungs in 25%, but also any other organs can be potentially involved in developing echinococcal disease. We report a case of extrahepatic, retroperitoneal echinococcal disease, caused by Echinococcus granulosus. The patient underwent a surgical removal of the abdominal mass, revealed by abdominal ultrasound and computerized tomography scanning, and in the founded clinical and radiological suspicion of echinococcal disease, multiple bioptical samples were sent for microbiological analysis and albendazole therapy was started; Echinococcus granulosus protoscolices were found on the bioptical sample, and the diagnosis was successfully confirmed. According to the current parasitology literature on echinococcal disease, extrahepatic localization, although rare, can be found, and it should be considered in the differential diagnosis of an abdominal mass when epidemiological risk factors and anamnestic data are present, regardless of the usual site of the disease.