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Presentation

Key Dermoscopic Features of Melanoma and How to Distinguish Them from Benign Nevi

Description

This talk reviews key dermoscopic features that help distinguish melanoma from benign nevi, emphasizing that pattern recognition must be interpreted in clinical context such as age, skin type, and sun damage. It begins with normal nevus patterns—reticular, globular, and homogeneous—and contrasts them with melanoma-specific clues including atypical network, irregular blotches, angulated/rhomboidal lines on sun-damaged facial skin, negative network, irregular peripheral globules, irregular streaks, regression structures (gray peppering and scar-like white depigmentation), blue-white structures, shiny white streaks, and polymorphous vessels. The speaker stresses that melanoma often shows asymmetry, chaos, and abnormal growth patterns, while benign lesions remain organized and symmetric. Several quiz examples illustrate common mimics such as solar lentigo, pigmented BCC, seborrheic keratosis, inflamed lesions, and blue nevi. Practical pearls include biopsying lesions with blue pigment, recognizing sparkly shiny white streaks with polarized light and dermatoscope rotation, and paying close attention to pink or “strawberry milkshake” lesions with atypical vessels. Overall, the message is to combine dermoscopic features with clinical judgment and biopsy suspicious lesions early.

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Conclusions

Dermoscopy can distinguish benign nevus patterns from melanoma-specific structures by looking for asymmetry, irregular network changes, atypical blotches, and abnormal growth patterns.
Atypical pigment network and angulated or rhomboidal lines are important clues to melanoma, especially on sun-damaged facial skin.
Negative pigment network within a nevus is a strong warning sign that melanoma may be arising in that lesion.
Irregular peripheral globules and irregular streaks or pseudopods suggest asymmetric growth and generally warrant biopsy rather than observation.
Regression features such as peppering and scar-like depigmentation indicate prior immune destruction of tumor and should raise concern for melanoma.
Blue-white structures and deep blue pigment imply deeper dermal pigment and should prompt a deeper biopsy approach to avoid sampling error.
Shiny white streaks that sparkle when the dermatoscope is rotated are a useful marker of melanoma-associated fibrosis.
Polymorphous or atypical vessels are a major clue to pink or hypomelanotic melanoma and help distinguish it from benign vascular lesions.
Context matters greatly: age, skin type, and lesion location can make some patterns normal in one patient but suspicious in another.
Overall, the presentation argues that recognizing a combination of melanoma-specific dermoscopic clues allows earlier biopsy and detection of thin melanomas before they become more advanced.

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Berry clinical photos; ISIC