precancerous skin lesions - woman in white tank top with moles

Precancerous Skin Lesions

As the name implies, precancerous skin lesions act as warning signs that skin cancer could develop. When left untreated can further spread to other organs.

In this article, we’ll review four types of precancerous skin lesions and how to identify them. We’ll also cover signs when benign lesions turn cancerous.

precancerous skin lesions - woman tanning in sun

Actinic Keratosis and Actinic Cheilitis

A common precancerous skin condition is actinic keratosis, also known as solar keratosis. This skin lesion forms on the skin damaged by long-term exposure to ultraviolet rays from sun or tanning beds. While most cases of actinic keratosis will not turn into cancer, about 5-10% of them will develop into squamous cell skin cancer. For this reason, doctors recommend early treatment.

Those with fair skin, blonde or red hair, live in sunny places, or work outdoors are at higher risk of developing this precancerous skin lesion. These skin lesions commonly occur on the face, neck, hands, and forearms. This is because these areas are more often exposed to the sun.

These skin lesions are rough, dry, and scaly, about one inch or less in diameter, and tend to develop slowly. The patches are flat, slightly raised, or may look like a wart. The color varies from pink to red or brown. The affected skin is itchy and bleeds easily. Actinic keratosis is usually diagnosed in individuals over 40.

You can prevent actinic keratosis by avoiding excessive sun exposure and tanning beds. Use sunscreen and check your skin often. Tell your doctor if you notice changes.

Actinic keratosis can be removed with drugs like fluorouracil and imiquimod or treatments like cryotherapy, curettage, or laser therapy.

You or your doctor can remove this precancerous skin lesion. Drugs such as fluorouracil and imiquimod can be used. Treatments like cryotherapy, curettage, and laser therapy are also effective.

Another related precancerous skin lesion that can lead to squamous cell carcinoma is actinic cheilitis. It usually develops on the lower lip. The lesion presents as a scaly patch that is rough and swollen. Your lips lost the natural border along the skin. Like actinic keratosis, you should treat it to prevent complications.

precancerous skin lesions - checking moles on woman's back with magnifying glass

Moles: Common Moles and Atypical Moles

Also known as nevus, a mole is a benign growth of the melanocytes, the pigment cells that give skin its color. The common moles rarely turn into cancer. It’s important to know the warning signs that suggest a mole is cancerous.

Normal, common moles are flat or raised and their surface is smooth. They have a regular shape, usually round or oval, and an even tan or brown color. They often develop during childhood or at a young age and are about half an inch in diameter.

When a mole has become cancerous, it becomes larger in size, has irregular shapes, and changes in shape or texture. They may also become harder or lumpy, feel itchy, bleed easily or ooze, and contain many colors.

There are also “atypical “ moles called dysplastic nevi. They tend to be larger than common moles and contain different colors ranging from pink to dark brown. They are usually flat and their edges tend to fade into the surrounding skin. A person who has more than five atypical moles is 10 times more likely to develop melanoma, compared to someone who has none.
Regarding common moles, some research studies indicate that having 50 or more common moles increases the risk of melanoma. For women, an increased number of moles may have a higher risk of developing breast cancer.

Most moles do not require treatment. Moles can be easily removed with minimally invasive procedures like shave removal, laser removal, or freezing (cryotherapy). If your doctor suspects a mole to be cancerous, they may take a sample for biopsy.

precancerous skin lesions - letter blocks stacked on top of each other

The ABCDE Rule of Skin Cancer

The easiest way to remember the warning signs that suggest a precancerous skin lesion has turned into skin cancer is to think of ABCDE.

A stands for asymmetrical shape. One-half of the lesion is unlike the other half.

B is for the border. Irregular or notched borders are a sign of cancerous skin lesions. Borders of benign skin lesions are regular.

C stands for color. A skin lesion that contains multiple colors, or has changed in color is more likely to be cancerous compared to lesions that have an even color.

D is for diameter. Smaller lesions tend to be benign, while lesions with diameters larger than ¼ inch (or the size of a pencil eraser) should be investigated. See your doctor for evaluation if a lesion becomes larger rapidly.

Lastly, E means evolving. Look for changes in more than just size. Examine changes in shape, color, height, and symptoms of itching and bleeding. These are all signs that suggest the skin lesion could be cancerous, especially melanoma.


It is important to examine your skin from head to toes, on a regular basis. Precancerous skin lesions could look normal if you aren’t aware of the signs. Melanoma, for example, is more often found on the back in men and on the lower leg in women. If you notice a suspicious-looking mole, make sure you visit your doctor for a complete evaluation.

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