Dermoscopic Evolution of Pediatric Nevi

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.