Abstract
Hydatid disease is caused by larva of genus Echinococcus. Echinococcus granulosus is the most common cause of hydatid disease in humans. This disease occurs either through direct ingestion of parasite eggs from contact or from the contaminated water or food. The disease most commonly occurs in the liver (80%) and the lungs (15%). Bone hydatidosis is very rare (0.5%-2.5%). Here, we present a case of hydatid cyst of the femur in a 34-year-old woman presented with pain and mass increasing in size. X-ray finding revealed an osteolytic cystic lesion of the metaphyseal part of the femur. The patient was operated with the probable diagnosis of a tumoral bone lesion. After excision, histopathologic finding showed bone hydatid cyst and the patient was treated by albendazole.