Melanoma in situ: Part I. Epidemiology, screening, and clinical features.

The incidence of melanoma has steadily increased over the past 3 decades, with melanoma in situ comprising a disproportionately high percentage of the rising incidence. Our understanding of melanoma in situ has been shaped by epidemiologic and clinical studies. Central to a review of melanoma in situ is a focus on its epidemiology, pathology, biologic behavior, treatment, and clinical outcome, which may differ significantly from that of malignant melanoma. Part I of this continuing medical education article reviews the epidemiology, risk factors, and clinical features of melanoma in situ; part II covers the histopathology, treatment options, and clinical management.