Variables predicting change in benign melanocytic nevi undergoing short-term dermoscopic imaging.

OBJECTIVE: To determine whether certain patient demographics are associated with poorer specificity for the diagnosis of melanoma in nevi undergoing short-term sequential digital dermoscopic imaging.

DESIGN: Retrospective cohort study performed from April 1, 1998, through May 31, 2007.

SETTING: Sydney Melanoma Diagnostic Centre, a tertiary referral institution.

PATIENTS: A total of 2497 benign melanocytic lesions in 1765 patients undergoing short-term sequential digital dermoscopic imaging during 2.5 to 4.5 months (42.3% male; mean [SD] age, 40 [14] years; age range, 1-86 years).

MAIN OUTCOME MEASURES: Proportion of changed nevi as a function of age, sex, lesion diameter, and anatomical site.

RESULTS: The only variable significantly associated with nevus change was age group (P = .002). When compared with the middle-aged (aged 36-50 years) group, the odds of change were significantly increased in the child and adolescent (aged 0-18 years: odds ratio, 2.60; 95% confidence interval, 1.30-5.22), young adult (aged 19-35 years: 1.50; 1.04-2.17), and elderly (> 65 years old: 2.04; 1.04-3.99) age groups. Within the changed benign lesions, a significant association was observed between histologic subtype and age group (P = .01). The proportion of changed lesions of the banal nevi type decreased and the proportion of the dysplastic nevi type increased with age. In the elderly group, 75.9% of changed lesions were of the dysplastic nevi type compared with 35.7% in the youngest group.

CONCLUSION: A poorer specificity is observed for the diagnosis of melanoma for nevi undergoing short-term sequential digital dermoscopic imaging in children and adolescents (75.7%) and elderly patients (77.9%) compared with other patients (84.6%).