Cystic tuberculosis of the bone mimicking osteogenic sarcoma.

Hong Kong has a relatively high incidence of tuberculosis in comparison with other developed cities, possibly due to the influx of mainland Chinese immigrants and Vietnamese boat people. However, primary, solitary cystic tuberculous infection of the bone is rare and few cases have been reported. Radiological appearances of this disease can mimic several bone conditions, including bone cyst, osteoblastoma and even osteosarcoma. We report on a case of a healthy fifteen-year-old who presented with swelling to the left elbow; biopsy confirmed this as cystic tuberculosis of the bone.