[1] St Thomas Hosp, St Johns Inst Dermatol, Skin Tumour Unit, London, England
[2] Hope Hosp, Dept Dermatol, Salford M6 8HD, Lancs, England
[3] Great Ormond St Hosp Children, Dept Dermatol, London WC1N 3JH, England
[4] Univ Dent Hosp, Dept Oral Med, Manchester, Lancs, England