A lentigo maligna looks like an ordinary, harmless sun spot or large freckle — a flat brown or tan patch on sun-damaged skin, usually the face, in older adults. But it is an early, slow-growing form of melanoma. Left alone, some turn invasive (lentigo maligna melanoma). Here is how to tell it from a harmless age spot, and how to get a spot reviewed if you are unsure.
2 More than one colour — tan, brown and near-black in the one spot
3 A darker focus within the patch — uneven, concentrated pigment
4 A separate darker spot nearby — pigment spreading unevenly
What lentigo maligna is
Lentigo maligna is the slowest-growing type of melanoma. It begins as a flat, irregular tan-to-brown patch on skin that has had years of sun — most often the face, and also the ears and neck. It can sit there for years looking like a stubborn age spot, which is exactly why it gets ignored. While it stays on the surface (in situ) it is highly treatable; if it grows down into the skin it becomes lentigo maligna melanoma, which is more serious.
Sun spot or lentigo maligna? How to tell
They can look almost identical, but there are clues:
- A harmless sun spot (solar lentigo) is usually an even light-to-mid brown, with a smooth, well-defined edge, and it stays the same over time.
- Lentigo maligna tends to be larger (often well over 6 mm), with an irregular or notched border, more than one colour (tan, brown, black, sometimes pink or red areas), and it slowly enlarges or changes over months to years.
The ugly-duckling rule helps too: a spot that stands out from your other sun spots, or one that is slowly changing, is worth a look — even if it seems minor.
Where it appears and who is at risk
It is a condition of chronically sun-exposed skin in older adults — fair skin, years of outdoor sun, and increasing age all raise the risk. The face (cheeks, nose, forehead) is the classic site, followed by the ears and neck.
Why acting early matters
Because lentigo maligna grows slowly and looks harmless, it is often left for years — and the longer it goes, the greater the chance it becomes invasive. Caught early, it can usually be removed surgically. So a changing “age spot” on sun-damaged skin is worth checking sooner rather than watching indefinitely.
Get a spot reviewed
Use Skin360AI to keep photos of the spots you want to watch connected over time. A spot can be a mole, freckle, mark, lump, sore, patch or any skin area. A photo record is not a diagnosis or an all-clear. If a spot is new, changing, bleeding, painful, growing, not healing or worrying you, arrange an in-person GP or skin-cancer clinic assessment. Related: age spots or skin cancer?, sun spots or skin cancer? and what melanoma looks like.
This is general information, not a diagnosis, and a photo cannot rule skin cancer in or out. Any spot on sun-damaged skin that is enlarging, changing, has an irregular border or more than one colour should be seen in person by your GP or a skin-cancer clinic.