Echinococcosis granulosus/cysticus of the tibia.

Hydatid disease is caused by the parasitic tapeworm Echinococcus. There are three species: E. granulosus, E. alveolaris and E. voegeli. Only E. alveolaris and E. granulosus are important for human infections. These two species are totally divergent in their manner of infestation. Hydatid disease is a rare parasitic disease that primary involves the liver and the lung. Skeletal disease is rare, accounting for less than 2% of all hydatid lesions, and often presents as a clinical and radiologic diagnostic problem. The skeletal involvement is usually due to secondary extension after haematogenous spread of the infection. The vertebral column, the pelvis and the skull are most commonly involved. Treatment is also difficult because of the invasive nature of bony involvement and the spillage of fluid with subsequent contamination seeding. We present a case of primary hyatid cyst of the tibia. We point out the importance of considering osseous hydatidosis in the differential diagnosis of destructive bone lesions and the necessity of radical resection.