Dermoscopy Use Leads to Earlier Cutaneous Melanoma Diagnosis in Terms of Invasiveness and Size? A Single-Center, Retrospective Experience

Background: The incidence of cutaneous melanoma has risen in recent years. The aim of this study was to compare cutaneous melanomas diagnosed at the Dermatology Unit of Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy, from 2006 to 2020 and between two specific biennia, i.e., 2006–2007 and 2019–2020. Methods: Retrospective chart review, with dermoscopic image collection, of cutaneous melanomas diagnosed at the Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy, from 1 January 2006 to 31 December 2020 Results: A statistically significant increase was shown in the proportions of in situ melanoma and melanoma measuring less than 6 mm, i.e., small-diameter melanoma (SDM), across the studied period (p < 0.001). Moreover, in the biennium 2006–2007, among 220 melanoma diagnoses, 6 were in situ (2.7%), as compared with 68 melanomas in situ out of a total of 236 (28.8%) melanomas diagnosed in the biennium 2019–2020. A statistically significant difference in the proportion of in situ melanoma between the two biennia was demonstrated (p < 0.001). Furthermore, during the first biennium, 27/220 (12.3%) SDM were identified, as compared with 61/236 (25.9%) in the last. A statistically significant difference was shown in the proportion of SDM between the two (p < 0.001). Conclusions: The percentage of in situ melanomas and those that can be detected at a diameter <6 mm has increased. The latter has been shown to be around one-third of excised lesions, thus undermining the practicality of the ABCD mnemonic. Dermoscopic criteria for SDM are needed to help further refine melanoma diagnosis.