Dermoscopic Clues for Diagnosing Amelanotic Melanoma and Its Mimics

Conclusions

• Amelanotic and lightly pigmented melanoma can closely mimic basal cell carcinoma, squamous cell carcinoma, dermatofibroma, and inflammatory dermatoses, so a low threshold for biopsy is warranted when the pattern is not classic.
• For melanoma, especially subtle lesions, light brown featureless areas, milky pink/red areas, disorganization, and blurry or polymorphous vessels are key clues.
• Basal cell carcinoma is favored by crisp arborizing vessels, characteristic pigmented structures, and a tendency to ulcerate even when very small.
• Squamous cell carcinoma with pigment can mimic melanoma, but medium brown pigmentation, keratinization, and keratin pearls support SCC.
• Dermatofibroma is usually more organized, with a central scar-like area and a relatively symmetric or lace-like peripheral pattern, whereas melanoma tends to be more globally disorganized.
• Melanomas that look inflammatory or nonspecific are often initially misread, so unilateral, nonresponsive, minimally scaly, depigmented lesions should prompt reconsideration and biopsy.
• Lentigo maligna on the face has special follicular patterns, and perifollicular linear projections are an important newer diagnostic clue.
• An inverse diagnostic approach for facial lesions—first excluding actinic keratosis, lichen planus-like keratosis, seborrheic keratosis, and similar benign patterns—can improve recognition of lentigo maligna.
• Because facial lentigo maligna overlaps clinically and dermoscopically with AK, SK, and other benign facial lesions, checklist-based assessment is helpful but not perfect.
• Overall, the presentation emphasizes that careful pattern recognition, comparison with mimics, and biopsy of suspicious outliers are essential to avoid missing melanoma and lentigo maligna.