Dermoscopy of Melanoma and Naevi

Abstract

Abstract Dermoscopy is a non‐invasive, in vivo imaging technique known to increase the diagnostic accuracy for melanoma and improve the benign‐to‐malignant biopsy ratio by increasing the detection of melanoma while decreasing the number of naevi being biopsied. Melanocytic naevi are the primary lesions in the differential diagnosis of early melanomas. While the clinical morphology of naevi and melanoma often overlap, dermoscopy has improved the ability to discriminate between the two by visualisation of colours and structures that are otherwise not visible to the naked eye. In general, naevi tend to display a symmetrical and organised dermoscopic pattern while melanomas tend to reveal melanoma‐specific structures distributed in an asymmetrical and disorganised manner. The structures found to be associated with melanoma on non‐glabrous skin include atypical network, negative network, streaks, shiny white lines, atypical dots/globules, off‐centred blotch, blue‐white veil, regression structures, atypical vessels and peripheral tan structureless areas. Due to the unique microanatomy of other anatomical sites such as the face and glabrous skin, additional dermoscopic features have been identified that help in the detection of melanoma in these sites. This chapter provides an overview of the dermosocopic structures and patterns associated with naevi and outlines the dermoscopic structures associated with melanoma.