Reflectance confocal microscopy accurately discriminates between benign and malignant melanocytic lesions exhibiting a ‘dermoscopic island’

Background The ‘dermoscopic island’ is a term that was recently proposed to design an area of a pigmented lesion with a uniform dermoscopic pattern different from the remainder of the lesion. The positive predictive value of this sign for the diagnosis of melanoma is about 50%. Objective The purpose of our study was to see if reflectance confocal microscopy (RCM) permitted to accurately distinguish between nevi and melanoma in such lesions. Methods Five lesions of five consecutive unselected patients, with a dermoscopic island but no feasible clear cut diagnosis on the basis of dermoscopy alone were examined by RCM before excision for histopathological evaluation. Results Two lesions corresponded to nevi, and three lesions were early melanomas arising on a benign naevus in one case, and on a dysplastic naevus in two cases. In all five cases, RCM permitted to make the correct diagnosis, with a very good correlation with conventional histopathology. Conclusion Reflectance confocal microscopy appears as a promising tool not only to enhance the early diagnosis of melanoma but also to avoid unnecessary excisions of lesions with a dermoscopic island.