Improving melanoma diagnosis by means of in vivo confocal laser microscopy

Confocal reflectance microscopy (CRM) enables the in-vivo observation of the skin at a nearly histologic resolution. Since melanin represents a strong source of contrast, this technique appeared particularly indicated for the study of melanocytic lesions. Cytological and architectural features of melanocytic skin lesions were studied on 25 melanomas and 50 atypical melanocytic nevi employing CRM (Vivascope 1000, Lucid Inc., USA) and digital dermoscopy (Videocap 200, DS-Mediroup, Italy). All lesions were excised for diagnostic confirmation. Some differences in CRM features were observed between benign and malignant lesions: in melanocytic nevi, cells were usually round to oval, mainly located in the basal layers or clustered into nests within the papillary dermis. Melanomas were characterized by numerous large cells within the superficial layers of the epidermis, suggesting a pagetoid fashion, and by cells polymorphic in size and shape mainly located in the basal layer, sometimes interrupted by small dermal papillae irregularly distributed throughout the lesion, owing to disarrangement of the normal architecture of the rete ridges. Moreover, large irregular cells with refractive cytoplasm and eccentric dark nucleus infiltrating dermal papilla and cell clusters with a multilobulated feature constituted by sparse cells or with a cerebriform aspect were specifically observed in melanomas. Although preliminary and based on a limited number of cases, these findings show the potential of this technique for the noninvasive diagnosis of clinically difficult lesions.