Dermoscopy Diagnosis of Facial and Acral Melanoma

Conclusions

• Facial dermoscopy follows different diagnostic rules than non-facial skin, because benign nevi on the face often show a pseudo-network rather than a regular pigment network.
• For lentigo maligna on the face, the key dermoscopic clue is pigment tracking down hair follicles, producing features such as annular-granular gray dots, asymmetric follicular openings, rhomboidal structures, and homogeneous blotches.
• Gray dots alone are not specific for melanoma, so their distribution and associated follicular patterns matter more than their mere presence.
• Pigmented actinic keratosis and lentigo maligna can look very similar dermoscopically, so diagnosis often depends on combining multiple features rather than relying on a single sign.
• When facial pigment hugs or thickens around follicular openings in an asymmetric, geometric, or rhomboidal way, melanoma becomes much more likely.
• Homogeneous areas or blotches that progressively obscure follicular openings are a strong sign of more advanced facial melanoma.
• Multiple melanoma-associated dermoscopic features can coexist in the same lesion, and seeing several of them together increases diagnostic confidence.
• A lone suspicious lesion on otherwise relatively clear facial skin should raise concern, even if the lesion is subtle clinically.
• On acral skin, pigmentation on the ridges is concerning for melanoma, whereas pigmentation in the furrows is usually benign.
• The parallel ridge pattern is the most important acral melanoma clue and is generally an indication for biopsy.
• If an acral lesion does not show parallel ridge pattern, typical benign patterns such as parallel furrow, lattice-like, and fibrillar patterns support reassurance rather than biopsy.
• The fibrillar pattern is usually a modified parallel furrow pattern, but on the palm it should be treated with extra caution and often biopsied.
• The BRAAFF scoring approach can help stratify non-typical acral lesions, and a score of one or more supports biopsy.
• Acral melanoma often becomes easier to recognize as it advances because it develops conventional melanoma-specific structures and multiple-component patterns.
• Not all parallel ridge pattern lesions are melanoma, because congenital acral nevi, hemorrhage, exogenous pigment, and some skin-of-color lesions can mimic it.
• Subcorneal hemorrhage can mimic acral melanoma, but paring or scraping that makes the lesion disappear supports blood rather than malignancy.
• In skin of color, acral lesions may not fit standard algorithms perfectly, so lesion size and evolution become especially important.
• Congenital acral nevi can look atypical and change over time, but this is often normal and pediatric acral melanoma is rare.
• The overall approach to acral lesions is to first look for parallel ridge pattern, then for benign typical patterns, then for melanoma-specific structures, and finally use size and follow-up when the diagnosis remains uncertain.
• Across both facial and acral sites, the central conclusion is that pattern recognition, lesion context, and combining several dermoscopic clues are more reliable than any single feature alone.