SAPHO syndrome: 20-year follow-up.

Considerable attention has been paid in the past 10 years to the radiological spectrum of disease entities belonging to the SAPHO syndrome. We report an unusual case presenting with an extra-axial (femoral) lesion, prior to description of this syndrome, which was radiologically and histologically mistaken for a parosteal osteosarcoma. Nineteen years later, a further lesion developed in the scapula together with the typical sternoclavicular manifestations, at which stage the correct diagnosis of SAPHO syndrome was established.