[A giant hydatid cyst localized in pelvis and thigh].

A hydatid cyst is a parasitic disease which is caused by a cestode named Echinococcus and often located in the liver. Localization in the bone and soft tissue is rarely seen. In this article, we present a 64-year-old male case with a hydatid cyst located in the soft tissue of the left anterolateral aspect of the thigh. The hydatid cyst starting from the gluteal region proximally into the pelvis, the femoral head and the hip joint leading to the spread of secondary protrusio acetabuli and extending distally to the popliteal region formed a massive lesion. In addition to medical treatment followed by repeated surgeries, the patient with relapses is still under surgical follow-up and medical treatment.