Recognizing Amelanotic and Hypomelanotic Melanoma: Dermoscopic Clues and Biopsy Approach

Conclusions

• Amelanotic and hypomelanotic melanoma can present as subtle pink lesions, sometimes with only a tiny brown focus or no visible pigment at all.
• A “brown dot in a pink spot” should raise suspicion for hypomelanotic melanoma and prompt careful evaluation.
• When the clinical appearance and dermoscopic findings do not match, biopsy should be strongly considered.
• White shiny lines or crystalline structures, especially when arranged perpendicularly, are a concerning dermoscopic clue for melanoma and often suggest invasive disease.
• White shiny areas/blotches and rosettes can also appear in other lesions, so they must be interpreted in context rather than in isolation.
• Scar-like depigmentation and milky red structureless areas are additional dermoscopic clues that can support the diagnosis of amelanotic melanoma.
• Atypical polymorphous vessels, especially a combination of dotted and linear irregular vessels, are highly suggestive of melanoma.
• As melanoma becomes thicker, vascular patterns tend to become more varied and more prominent.
• Nonpigmented Spitz nevi can closely mimic amelanotic or hypomelanotic melanoma, making histologic confirmation important in older patients.
• Symmetric pink lesions with unusual vessels should not be dismissed and should generally be biopsied.
• Partial biopsies can miss the diagnosis, so adequate depth and sampling of the whole lesion matter when melanoma is suspected.
• Overall, the key practical message is that a pink lesion with atypical vessels and white shiny structures should be treated as melanoma until proven otherwise.