Isolated musculoskeletal hydatid disease: diagnosis on fine needle aspiration and cell block

Hydatidosis is a zoonotic infection caused by Echinococcus granulosus. The most common sites of involvement are liver and lungs. Isolated musculoskeletal hydatidosis in absence of visceral involvement is rare and it mimics bone or soft tissue neoplasm. Fine needle aspiration cytology and cell block aids in diagnosis in such unusual location. Here we present one such rare case of isolated musculoskeletal hydatidosis diagnosed on fine needle aspiration cytology and cell block which was mimicking as fibrous dysplasia on radiology.