Lentigo Maligna vs Seborrheic Keratosis

How to tell the difference — key features compared side by side.

Feature
Lentigo Maligna
Seborrheic Keratosis
Category
Malignant
Benign
Key feature
The earliest stage of a specific melanoma type. A slowly expanding flat brown patch on sun-damaged facial skin.
Waxy, stuck-on growths - the most common benign tumor in adults over 50. Harmless but frequently mistaken for melanoma.
Risk factors
Chronic cumulative sun exposure on fair skin; Age over 60 (median age 65-70); History of significant sun damage (solar elastosis)
Age over 50 (prevalence approaches 100% in elderly); Genetic predisposition (strong familial tendency); Sun exposure may play a role in some cases
Action needed
A flat brown patch on the face that has been slowly expanding
Only if you are unsure whether a growth is SK or melanoma

Lentigo Maligna

Lentigo maligna (LM) is a form of melanoma in situ - meaning the malignant melanocytes are confined to the epidermis and have not yet invaded deeper layers. It occurs on chronically sun-damaged skin, most commonly the face (especially the cheeks, nose, and forehead) of elderly individuals.

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Seborrheic Keratosis

Seborrheic keratosis (SK) is the single most common benign skin tumor, affecting nearly all adults over 60. They appear as waxy, raised, brown or tan growths that look as though they have been pasted or stuck onto the skin surface.

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Does yours look more like lentigo maligna?

Quick self-check

Does this look like lentigo maligna? Answer 2 questions.

Is it a flat brown patch on sun-damaged facial skin?

Has it been slowly growing or changing over months to years?

Still not sure?

Our full ABCDE checker evaluates 5 clinical criteria dermatologists use.

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