Comparison of dermoscopic features between congenital and acquired acral melanocytic nevi in Korean patients

Background: The dermoscopic patterns of acral melanocytic nevi (AMNs) are crucial in differentiating them from acral melanoma. Several studies have reported the dermoscopic patterns of acquired acral melanocytic nevi (AAMNs). However, few have investigated the dermoscopic patterns of congenital acral melanocytic nevi (CAMNs).

Objective: To compare the clinical and dermoscopic features of CAMNs and AAMNs.

Methods: The present study included 43 patients with CAMNs and 40 with AAMNs. We reviewed their medical records as well as their clinical and dermoscopic findings.

Results: Congenital acral melanocytic nevis were more asymmetrical than AAMNs (P = 0.002) and presented more frequently as comma-shaped (P = 0.005). Regarding dermoscopic findings, globular pattern (55.8%) was the most common feature of CAMNs, while parallel furrow pattern (37.5%) was the most common feature of AAMNs. The presence of fibrillar, globular, and parallel ridge patterns, and diffuse multi-component pigmentation differed significantly between the groups (P < 0.05). Furthermore, CAMNs showed melanoma-specific dermoscopic patterns, such as parallel ridge (18.6%) and diffuse multi-component pigmentation (25.6%).

Conclusion: The dermoscopic patterns of CAMNs and AAMNs differed markedly. In terms of dermoscopic patterns, CAMNs resembled acral melanoma more often than AAMNs did.