In an earlier five-continent study comparing dermoscopic features of 222 amelanotic melanomas, 105 pigmented melanomas, and 170 benign melanocytic lesions, investigators came up with a simple model that distinguished melanomas from nonmelanomas with 70% sensitivity and 56% specificity. The take-home message: Amelanotic melanomas often feature more than one shade of pink upon dermoscopic examination, along with dotted and linear irregular vessels and predominant central vessels (Arch Dermatol. 2008;144[9]:1120-7).
Nevoid melanoma: Clinically they often resemble an intradermal nevus, and they’re often amelanotic. Dermoscopically, however, an intradermal nevus displays a mammillated surface, with each individual mammillated area being associated with an isolated comma or hairpin vessel. In contrast, the surface of a nevoid melanoma is more undulating in appearance and lacks the classic vascular pattern seen in intradermal nevi. If there’s pigmentation present in a nevoid melanoma it will be distributed heterogeneously. The dermoscopic finding of irregular blood vessels and/or crystalline structures tips the balance in favor of biopsy.
Dr. Marghoob referred dermatologists interested in the dermoscopic features of nevoid melanoma to a recent study by members of the International Dermoscopy Society; he was one of the authors (Br J Dermatol. 2015;172[4]:961-7).
Epidermotropic metastatic melanoma: These lesions lack the ABCDs, are often amelanotic, and look like nondescript papules. If such a lesion is new, especially in a patient with a history of melanoma, think epidermotropic metastatic melanoma.
Spanish dermatologists have described five different dermoscopic patterns of melanoma metastases in an informative retrospective study: blue nevus-like, angioma-like, nevus-like, vascular, and unspecific. The vascular type is the most common form, characterized by amelanotic papules 2-3 mm in diameter and tortuous corkscrew vessels within the lesions (Br J Dermatol. 2013;169[1]:91-9).
Dr. Marghoob reported having no financial conflicts of interest regarding his presentation. SDEF and this news organization are owned by the same parent company.