1. From the Division of Rheumatology (C.S.), Azienda USL-IRCCS di Reggio Emilia and Università of Modena and Reggio Emilia, Italy; Division of Rheumatology (G.G.H.), Department of Anatomic Pathology (C.G.), Department of Radiology (J.H.), and Department of Neurology (R.D.B.), Mayo Clinic, Rochester, MN.