The ringlike pattern in vulvar melanosis: a new dermoscopic clue for diagnosis.

Background: Vulvar melanosis is a benign pigmented lesion that may clinically mimic melanoma. Whereas the dermoscopic features of other pigmented skin lesions have been extensively described, little is known about vulvar melanosis.

Observations: A retrospective dermoscopic study was conducted on 87 lesions with histopathologically proved melanosis. We describe and define, for the first time to our knowledge, a ringlike pattern, found in 28 of 87 melanotic lesions (32%), characterized by multiple round to oval structures, white to tan, with dark brown, well-defined regular borders. The structureless and globularlike patterns were observed in 18 of 87 lesions (21%), the parallel pattern in 15 (17%), and the cobblestonelike and reticularlike patterns in 4 (5%). A significant association was found between the distribution of multifocal lesions showing a ringlike vs a nonringlike pattern (82% vs 52%; P = .008), whereas a weak association was found between anatomical site and the different patterns (P = .55). The ringlike pattern was frequently combined with multifocality and simultaneous occurrence at the labia majora and the labia minora.

Conclusion: Dermoscopy can be useful for the clinical detection of vulvar melanosis, and the ringlike pattern may represent a new dermoscopic clue for the diagnosis of this lesion.