1. St John's Institute of Dermatology; London UK
2. Department of Dermatology; Charité-University Medicine; Berlin Germany
3. Department of Pathology; Universite Paris; Paris France
4. Department of Dermatology and Venereology; University of Zurich; Zurich Switzerland
5. CHRU; Lille France
6. Department of Dermatology Medical; University of Graz; Graz Austria
7. Department of Dermatology; University of L'Aquila; Rome Italy
8. Department of Pathology; University of Clermont-Ferrand; Clermont-Ferrand France
9. Department of Dermatology; Ghent University Hospital; Gent Belgium
10. Department of Pathology; Western General Hospital; Edinburgh UK
11. Department of Dermatology; University of Vienna; Vienna Austria
12. Department of Pathology; VU University Medical Center; Amsterdam the Netherlands
13. Hospital Universitario; Universidad Complutense; Madrid Spain
14. Departmentof Pathology; Dijon's University Hospital; Dijon France
15. Division of Dermatology; University of Florence Medical School; Florence Italy
16. Division of Pathological Anatomy; University of Florence; Florence Italy
17. Department of Pathology Henri-Mondor Hospital; University Paris-Val-de-Marne; Paris France
18. Department of Dermatology; Leiden University; Leiden the Netherlands
19. Department of Dermatology; Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico and Università degli Studi di Milano-Bicocca; Milan Italy