Dermoscopy for Melanoma

Abstract

Dermoscopy improves diagnostic sensitivity for melanoma diagnosis compared to clinical examination alone. The dermoscopic features characterizing non-glabrous skin melanoma are atypical network, irregular dots and/or globules, regression structures, blue-whitish veil, peripheral streaks, irregular blotches, atypical vascular structures, negative network, shiny white lines and brown peripheral structureless areas. Facial melanoma shows a different set of dermoscopic structures such as hyperpigmented asymmetric follicular openings, annular-granular pattern, rhomboidal structures and obliterated follicular openings. In acral melanoma, the two main patterns are the parallel ridge pattern and irregular diffuse pigmentation. Pigmented nail-unit melanoma is characterized by the presence of a brown/black background and by longitudinal lines within the band with irregular thickness, spacing, parallelism, and colour; sometimes a periungual spread of pigment called the Hutchinson sign is present. Nodular melanoma often lacks the classic melanoma-specific criteria; nevertheless, the simultaneous presence of blue and black areas involving at least 10% of the surface is strongly suspected for a malignant lesion. Amelanotic and hypomelanotic melanoma are relatively rare and featureless, and the most useful dermoscopic criteria are the presence of atypical vascular pattern and a milky red colour.