Risk of cutaneous malignant melanoma in patients with 'classic' atypical-mole syndrome. A case-control study.

Background and Design: There is an increased risk of developing cutaneous malignant melanomas (MMs) in patients with classic atypical-mole syndrome (AMS). This study compares the incidence of newly diagnosed MMs in patients with classic AMS (cases) with the incidence of newly diagnosed MMs developing in a population without classic AMS (control patients). The charts of 287 white patients with AMS and 831 white patients without AMS were reviewed for the occurrence of newly diagnosed invasive MMs during follow-up. Both cases and control patients were followed up regularly by total-body cutaneous examinations. The cumulative 10-year risk for developing newly diagnosed invasive MMs was calculated (life-table method) for each cohort.
Results: Of the 287 AMS cases, 10 developed a newly diagnosed invasive MM, resulting in a 10-year cumulative risk of 10.7%. Of the 831 control patients, two developed a newly diagnosed invasive MM, resulting in a 10-year cumulative risk of 0.62%.
Conclusion: Patients with classic AMS, regardless of the presence of a personal and/or family history of MM, are at significantly increased risk of developing invasive MMs compared with control patients.