Background: Hydatid cysts caused by Echinococcus sp can produce tissue cysts anywhere in the body. Skeletal cystic lesions are rare, yet because of their unusual presentation diagnosis can be missed.
Case report: We report a case of extensive hydatidosis of the femur with pathological fracture and involvement of the pelvis bone, without involvement of abdominal viscera, in a 51-year-old woman. The patient presented with swelling and deformity of the upper and middle third of the left thigh. The diagnosis was confirmed clinico-radiologically and the patient was treated with hindquarter amputation and chemotherapy. The patient died of sepsis and extensive bedsores one month after surgery.
Conclusions: Orthopedic surgeons should be alert to this morbid condition and this disease should be suspected in cystic lesions affecting any organ of the body in pathological fractures with non-union, especially in endemic areas of the world. Early diagnosis helps in eradication and salvage of the bone; misdiagnosis and delayed diagnosis are always fraught with the danger of amputation, recurrence, and sepsis.