Lentigo Maligna vs Actinic Keratosis

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

Feature
Lentigo Maligna
Actinic Keratosis
Category
Malignant
Pre-cancerous
Key feature
The earliest stage of a specific melanoma type. A slowly expanding flat brown patch on sun-damaged facial skin.
Rough, sandpaper-like patches from years of sun damage. The most common precancer - 5-10% progress to squamous cell carcinoma.
Risk factors
Chronic cumulative sun exposure on fair skin; Age over 60 (median age 65-70); History of significant sun damage (solar elastosis)
Cumulative lifetime sun exposure; Fair skin, light hair, light eyes (Fitzpatrick I-III); Age over 40
Action needed
A flat brown patch on the face that has been slowly expanding
Any rough scaly patch on sun-exposed skin persisting more than two weeks

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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Actinic Keratosis

Actinic keratosis (AK) is the most common precancerous skin lesion, affecting an estimated 58 million Americans. It develops from cumulative ultraviolet radiation damage and represents the earliest stage toward squamous cell carcinoma.

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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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