1 Unit of Dermatology, Department of Specialistic, Diagnostic and Experimental Medicine, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
2 Unit of Dermatology, Department of Specialistic, Diagnostic and Experimental Medicine, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy - alvirdi@libero.it.
3 Division of Pathology, Department of Health Sciences, University of Milan, San Paolo Hospital, Milan, Italy.