TL;DR: Key Takeaways
- Sun spots (solar lentigines) = flat, uniform, stable for years — benign
- Early melanoma can mimic a sun spot but shows uneven colour and slow growth
- The 5-second test: asymmetry + colour variation + change over time
- Lentigo maligna melanoma is the specific cancer that mimics age spots
- Photograph monthly — change is the strongest single warning sign
Part of the Sun Damage vs Skin Cancer hub.
At a Glance
| Feature | Sun Spot (Solar Lentigo) | Melanoma (Lentigo Maligna) |
|---|---|---|
| Colour | Uniform tan to medium brown | Multiple shades — tan, brown, dark brown, sometimes black or pink |
| Border | Smooth, well-defined | Notched, scalloped, or fading into normal skin |
| Shape | Round or oval, symmetric | Asymmetric — one half unlike the other |
| Size | 2–20 mm, stable | Often >6 mm at diagnosis, slowly enlarging |
| Texture | Completely flat, smooth | Mostly flat early; raised areas appear late |
| Location | Face, hands, shoulders, upper back — chronic sun exposure | Same areas, especially face in adults over 60 |
| Change over time | Stable for years | Slowly enlarges, darkens unevenly, develops new colours |
| Danger | None | Cancer — early treatment is curative; late treatment is not |
How a Sun Spot Looks
- Flat brown patch, completely smooth to the touch
- Uniform colour across the entire spot
- Round or oval with a clean border
- Usually appears alongside other similar spots in the same area
- Has been there unchanged for months or years
How Early Melanoma Looks
- Asymmetric — one half looks different from the other
- Multiple shades of brown, black, or pink within the same lesion
- Borders that fade, scallop, or notch instead of ending cleanly
- Slow but visible change in size or pigment over 3–12 months
- Stands out from your other spots ('ugly duckling' sign)
Not sure which one you have?
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The 5 Dermatologist Clues
- Asymmetry — fold the spot in half mentally; melanoma rarely matches
- Border quality — clean edge vs notched or fading
- Colour count — one shade vs three or more
- Diameter — sun spots are usually small; lesions over 6mm warrant attention
- Evolving — any change beats every other feature combined
Red-Flag Checklist
See a dermatologist within 2–4 weeks if your spot:
- Has darkened, enlarged or changed shape in the last 6 months
- Shows more than two colours within a single lesion
- Looks visibly different from every other age spot you have
- Is itching, bleeding, or has developed a raised area
- Appeared as a new pigmented spot after age 40
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Frequently Asked Questions
A true solar lentigo (age spot) does not transform into melanoma. However, lentigo maligna melanoma can develop on sun-damaged skin and look very similar to a sun spot in its earliest stage. Any age spot that changes shape or develops uneven colour needs evaluation.
Sun spots are stable over years. Most melanomas show visible change over 3–6 months — darkening, enlarging, becoming asymmetric, or developing multiple colours within the same lesion.
Lentigo maligna (melanoma in situ on sun-damaged skin) often starts as a flat tan-to-brown patch that slowly enlarges over years and develops uneven pigmentation. Unlike a sun spot, it has irregular borders and multiple shades.
No need to scan every one — but scan any spot that is changing, looks different from your other age spots, or is larger than a pencil eraser. The 'ugly duckling' principle applies.
AI dermatology tools are very effective at flagging suspicious pigmented lesions for review. They aren't a diagnosis, but they're a useful triage step before booking a dermatologist appointment.