BACKGROUND: In the early stages, vulvar melanoma can mimic vulvar melanosis and therefore the diagnosis is often late and carries a poor prognosis. In vivo reflectance-mode confocal microscopy (RCM) is an emerging technique that allows noninvasive high-resolution imaging of the skin and mucosa, but it has not been employed in the study of genital pigmentation.

OBJECTIVE: To analyze the characteristics of vulvar melanosis and vulvar melanoma using RCM to define the confocal aspects that allow a correct differential diagnosis.

METHODS AND MATERIALS: Features of eight melanoses and two melanomas of the vulva were analyzed using RCM. RCM diagnosis was then compared with clinical and histologic diagnosis.

RESULTS: Two major characteristics are associated with vulvar melanosis: papillae rimmed by bright monomorphous cells and possible presence of a few dendritic bright cells in the basal layer of the epithelium. Two major features of vulvar melanoma have been identified: atypical cells in the epithelium and loss of normal architecture of chorion papillae.

CONCLUSIONS: Reflectance Confocal Microscopy can play a role in noninvasive differentiation between vulvar melanoma and vulvar melanosis, but further broader studies are needed to validate our observations.