Dysplastic nevi. Markers for increased risk for melanoma.

A total of 452 white patients, classified into four dysplastic nevi groups, were followed prospectively by repetitive, complete cutaneous examinations using total-body photographs taken on entry into the study. Sixteen patients (3.5%) developed 18 newly diagnosed malignant melanomas (MM) during an average follow-up period of 27 months. Twelve of the 18 MM were in situ, and all of the six primary invasive MM diagnosed prospectively in this follow-up were less than 0.89 mm in Breslow thickness, implying an excellent prognosis. Compared with reference populations, the number of MM detected significantly exceeded the number estimated to occur in the comparable age-matched control groups. These data support the concept of repetitive follow-ups of all groups of patients with dysplastic nevi.