in or subscribe to access all of BMJ Best PracticeContributorsVIEW ALLAUTHORSYin Wu, MRCP(UK), PhDAmanda Fitzpatrick, MRCP(UK), PhDPablo Fernandez-Peñas, MD, PhD, FACDAcknowledgementsVIEW ALLPEER REVIEWERSDavid Cassarino, MD, PhDJames DeBloom, MDMai Brooks, MD, FACSKarol Sikora, MA, MBBCh, PhD, FRCR, FRCP, FFPMDifferentialsBenign/dysplastic melanocytic naeviSeborrhoeic keratosisPigmented basal cell