Frequency of Dermoscopic Nevus Subtypes by Age and Body Site: A Cross-sectional Study

Objective To subclassify acquired nevi by dermoscopic pattern. Design Cross-sectional study with consecutive enrollment. Setting Pigmented lesion clinics in referral academic medical centers. Participants Individuals older than 2 years undergoing total skin examination were consecutively recruited between October 1, 2008, and May 31, 2009, and, based on their age, assigned to 1 of 8 groups. For each patient, the location and dermoscopic pattern of all nevi on the torso were recorded. Nevi were dermoscopically subclassified as globular, reticular, mixed (reticular-globular) pattern with peripheral or central globules, or unspecified pattern. Main Outcome Measure Frequency of dermoscopic nevus subtypes stratified by patient age and location of the nevi. Results A total of 5481 nevi in 480 individuals were evaluated. The number of all nevus subgroups, except for unspecified pattern nevi, significantly increased before and decreased after the fourth decade of life. Globular nevi were most prevalent on the upper trunk in children and adolescents; the number decreased consistently after the second decade of life. The reticular pattern was the most common nevus pattern after the second decade of life and the most common nevus subgroup on the upper and middle back. Although uncommon, central globular nevi also showed an age-dependent trend, similar to that of reticular nevi. Nevi with the peripheral globular pattern declined rapidly after the third decade of life and were no longer observed after the sixth decade. The number of unspecified pattern nevi was stable across all age groups. Conclusion Age, dermoscopic pattern, and location of nevi should be jointly considered when evaluating melanocytic lesions.