LAUSR

Background The incidence of pediatric melanoma is very rare. Dermoscopic features help to distinguish pediatric melanoma and common nevi. Objective To study the evolution of dermoscopic findings in benign nevi in childhood through serial observation and photography. Methods We examined 504 melanocytic lesions in 100 patients. From each participant, dermoscopic images of the nevi from 4-year dermoscopic follow-up were obtained, including randomly selected nevi. Results The most common dermoscopic patterns were homogeneous (193 nevi; 38.3%), globular (92 nevi; 18.3%), and reticular (86 nevi; 17.1%). Dermoscopic pattern changes were detected in 27% of patients aged 2~10 years and in 20% of patients aged 11~16 years. The main pattern changes consisted of the transition from homogeneous to globular-homogeneous (16%), from homogeneous to reticular-homogeneous (12%) and from globular to globular-homogeneous (10%). Although 257 of the 504 nevi (51.0%) have stable duration without size changes, 169 of the 504 nevi (33.5%) were enlarged, and 78 of the 504 nevi (15.5%) had become smaller. Conclusion These results contrast with the prevailing view that dermoscopic patterns in pediatric nevi are usually characterized by globular patterns and that melanocytic nevi generally undergo a characteristic transition from a globular pattern to a reticular pattern. Fifty one percent of patients did not exhibit a size change. While 33% of patients had symmetrical enlargement, 15% of patients had involution. Therefore, enlargement is a common dermoscopic change in pediatric nevi, and is not a specific sign of pediatric melanoma.