Pathological femoral neck fracture caused by an echinococcus cyst of the vastus lateralis - case report

BACKGROUND: Musculoskeletal hydatid cysts are rare, but being locally invasive, can potentially cause significant deformity or pathological fracture. CASE PRESENTATION: A 39 y.o. male presented to our orthopaedic outpatient clinic complaining of severe right hip pain, and inability to ambulate. Symptoms were not preceded by trauma. Subsequent imaging confirmed a large, 17 × 3 × 5 cm echinococcus cyst in the vastus lateralis, causing erosion of the proximal metaphysis of the femur. As a consequence the patient suffered a non-traumatic pathological intertrochanteric femur fracture. The patient was treated with an en-bloc excision of the lesion - the affected soft tissue envelope containing the large cyst - and as a second surgical step a cemented total hip replacement (THR) was implanted under the same anaesthetic. The manuscript reviews the literature regarding musculoskeletal hydatid disease.