Spitz nevus and melanoma: evaluation with dermoscopy and reflectance confocal microscopy

Spitz nevi (SN) include a wide range of benign melanocytic nevi, which are controversial due to their morphologic resemblance to melanoma (MM).

To describe dermoscopic and reflectance confocal microscopic (RCM) features of SN compared to MM and assess the RCM utility in the differential diagnosis.

We performed a multicentre retrospective analysis of MM and SN evaluated with dermoscopy and reflectance confocal microscopy. Three RCM mosaics were obtained for each lesion. Nine dermoscopic and twenty-one microscopic features were assessed for each lesion.

A total of 26 lesions (15 SN and 11 MM) were included. Dermoscopically, most SN showed a "starburst" pattern. Asymmetry was marked in 8 MM. There were 6 dermoscopic features significantly more prevalent in MM than in SN. RCM showed that an atypical honeycomb pattern, atypical infiltration, and disarray of the epidermis were significant for MM. SN mostly revealed a typical honeycomb pattern. At the DEJ, most of SN had a meshwork pattern; MM revealed an atypical meshwork pattern. Atypical cells and sheet-like structures were observed in most MM.

A combined approach using dermoscopy and RCM supports the differential diagnosis of SN and MM. Although our study showed some significant differences between SN and MM in RCM, further research on a larger group should be considered.