Dermoscopic criteria associated with BRAF and NRAS mutation status in primary cutaneous melanoma

Background The identification of BRAF mutations in melanoma led to the development and implementation of new and effective therapies. Few clinical and histological features have been associated with this mutational status. Objectives The main objective of this study was to investigate clinical, histopathological and dermoscopic characteristics of primary melanomas according to BRAF or NRAS mutational status. Methods An observational retrospective study including melanoma dermoscopy images assessed for somatic mutations in BRAF and NRAS. Results Seventy-two patients were included, 30 women (42%) and 42 men (58%), mean age was 591551years. BRAF-mutated melanomas were more frequently located on the trunk (n=18, 64% for BRAF-mutated vs. n=11, 29% for wild-type melanomas, P=0013). Histological ulceration was associated with the presence of BRAF mutations [odds ratio (OR) 3141; 95% confidence interval (CI) 1289-7655; P=0002]. The Breslow index tended to be thicker in BRAF-mutated compared with wild-type (P=0086). BRAF mutations were present in 28 (39%) patients and only four cases were positive for NRAS mutations (6%), BRAF and NRAS mutations being mutually exclusive. The presence of dermoscopic peppering was associated with MAPK mutations (BRAF and NRAS) (OR 168; 95% CI 1089-2581; P=0015). Dermoscopic ulceration was also associated with BRAF mutations excluding acral and facial melanomas (OR 264; 95% CI 1032-6754). Conclusions This study showed a correlation between BRAF and NRAS status and dermoscopic findings of peppering' as an expression of regression and melanophages in the dermis, suggesting a morphological consequence of immune behaviour in BRAF-mutated melanomas.