Squamous Cell Carcinoma vs Actinic Keratosis

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

Feature
Squamous Cell Carcinoma
Actinic Keratosis
Category
Malignant
Pre-cancerous
Key feature
Second most common skin cancer. More aggressive than BCC - can spread to lymph nodes if not treated early.
Rough, sandpaper-like patches from years of sun damage. The most common precancer - 5-10% progress to squamous cell carcinoma.
Risk factors
Cumulative lifetime sun exposure (more important than acute burns for SCC); Fair skin (Fitzpatrick types I-III); History of actinic keratosis - the primary precursor lesion
Cumulative lifetime sun exposure; Fair skin, light hair, light eyes (Fitzpatrick I-III); Age over 40
Action needed
A firm, red nodule on sun-exposed skin that persists or grows
Any rough scaly patch on sun-exposed skin persisting more than two weeks

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) of the skin develops in the flat squamous cells that form the outer layer of the epidermis. It is the second most common skin cancer after BCC, with over one million cases diagnosed annually in the US.

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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 squamous cell carcinoma?

Quick self-check

Does this look like squamous cell carcinoma? Answer 2 questions.

Is the spot firm, raised, or nodular with a rough or scaly surface?

Is it on a chronically sun-exposed area (face, ears, hands, scalp)?

Still not sure?

Our full ABCDE checker evaluates 5 clinical criteria dermatologists use.

Full ABCDE check →