Hydatid bone disease of the femur.

Abstract

Osseous hydatid disease is caused by the parasitic tapeworm Echinococcus. The species most responsible for hydatid disease is Echinococcus granulosus, endemic especially in sheep-rearing districts like Mediterranean countries and Australia. In Turkey, the exact incidence of human hydatid disease is not known, but < or =34% of asymptomatic farmers have positive serology. Bone hydatidosis is rare, making up 0.5% to 4% of all cases. Patients usually present with pain, swelling, or pathological fracture. There are no specific radiographic signs in affected bone. In the later stages, lytic lesions with a trabeculated pattern, with or without sclerosis, may be seen. Computed tomography (CT) is still the best method for diagnosis and posttherapy follow-up of osseous hydatidosis. On CT, skeletal cystic hydatidosis appears as one or several closely related, well-defined, osteolytic lesions. There may be bone expansion, cortical thinning, cortical destruction, sclerosis, honeycomb appearance, and extension into adjacent soft tissues.