Osseous Hydatidosis of Femur in a Patient with Fracture Non-union: An Uncommon Entity.

Hydatid disease caused by the larval form of the parasitic tapeworm, Echinococcus granulosus, commonly affects the liver and lungs. Bone involvement by Hydatid is extremely uncommon and is reported in 1-3% of cases. It is often a dormant disease, presenting at a late stage with non-specific clinical and radiological findings. Usually they occur as an isolated entity without liver/lung involvement and a clinical suspicion of this disease is not possible. We report a rare case of Hydatid cyst of femur in a 25-year-old female, with unresolving non-union of fracture for five years. The occurrence of this disease in atypical locations and lack of a specific radiological sign makes the diagnosis challenging and it is important for the orthopaedicians and pathologists to be aware of this entity for a precise diagnosis.