Do we need to rethink the diagnoses melanoma in situ and severely dysplastic naevus?

DEAR EDITOR, Many countries have seen a dramatic increase in the reported incidence of cutaneous melanoma in recent decades, largely driven by increased diagnoses of melanoma in situ and thin invasive melanoma.The incidences of thick and metastatic melanomas, and melanoma mortality have remained relatively stable.While ageing populations could be Table 1 Evidence identified to support or reject a change to diagnostic thresholds and/or terminology used for melanoma in situ (MIS) and severely dysplastic naevus (SDN) Natural history studies: observation of MIS or SDN not actively treated or incompletely excised (partial or close margins) for ≥6 months.The collective 127 cases are underlined Study Country Study design Key findings Overall risk of bias Engeln, 2017 USA Retrospective chart review 286 people with SDN (140 with negative margins, 47 with close margins, 40 with positive margins, 3 with indeterminate margins, 56 margins not reported) observed for ≥5 years.0 cases of invasive melanoma at same site, metastasis, or deaths from melanoma High Fleming, 2020