Squamous cell skin cancer is a type of tumor that affects the skin.

Causes

Squamous cell cancer occurs when cells in the skin start to change. The changes may begin in normal skin or in skin that has been injured or inflamed. Most skin cancers occur on skin that is regularly exposed to sunlight or other ultraviolet radiation. Skin cancer is most often seen in people over age 50.

Squamous cell carcinoma in situ (also called Bowen's disease) is the earliest form of squamous cell cancer. The cancer has not yet invaded surrounding tissue. It appears as large reddish patches (often larger than 1 inch) that are scaly and crusted.

Actinic keratosis is a precancerous skin lesion. In rare cases it may become a squamous cell cancer.

Risks for squamous cell skin cancer include:

• Having light-colored skin, blue or green eyes, or blond or red hair
• Long-term, daily sun exposure (such as in people who work outside)
• Many severe sunburns early in life
• Older age
• A large number of x-rays
• Arsenic
• Chemical exposure

Squamous cell cancer spreads faster than basal cell cancer, but still may be relatively slow-growing. Rarely, it can spread (metastasize) to other locations, including internal organs.

Symptoms

The main symptom of squamous cell skin cancer is a growing bump that may have a rough, scaly surface and flat reddish patches.

The bump is usually located on the face, ears, neck, hands, or arms, but may occur on other areas.

A sore that does not heal can be a sign of squamous cell cancer. Any change in an existing wart, mole, or other skin lesion could be a sign of skin cancer.

Exams and Tests

Your doctor will check your skin and look at the size, shape, color, and texture of any suspicious areas.

If skin cancer is a possibility, a piece of skin will be removed from the area and examined under a microscope. This is called a skin biopsy. A biopsy must be done to confirm the diagnosis of basal cell carcinoma or other skin cancers.

There are many types of skin biopsies. The exact procedure depends on the location of the suspected skin cancer.

Treatment

See also: Actinic keratosis for treatment information

Skin cancer has a high cure rate if it is treated early. Treatment depends on how big the tumor is, its location, and how far it has spread (metastasis).

• Excision refers to cutting out the tumor and using stitches to place the skin back together.
• Curettage and electrodesiccation scrapes away the cancer and uses electricity to kill any remaining cancer cells. It is used to treat cancers that are not very large or deep.
• Mohs surgery involves cutting out a layer of the skin cancer and immediately looking at it under a microscope to check if any cancer has been left behind. More layers are removed until the skin sample is free of cancer. Mohs surgery is more likely to be used for skin cancers on the nose, ears, and other areas of the face.
• Cryosurgery freezes and kills the cancer cells.
• Radiation may be used if the cancer has spread to organs or lymph nodes, or for squamous cell cancers that cannot be treated with surgery.
• Skin creams and the medications imiquimod or 5-fluorouracil may be used to treat actinic keratosis and superficial (not very deep) squamous cell carcinoma.
• Photodynamic therapy, a special type of light treatment, may be used to treat Bowen's disease (BD).

Outlook (Prognosis)

Most (95%) of squamous cell tumors can be cured if they are removed promptly. New tumors may develop, however. If you have had squamous cell cancer, have your skin regularly examined by your health care provider.

The outlook depends on a number of factors, including the type of cancer and how quickly it was diagnosed. Squamous cell carcinoma only rarely spreads to other parts of the body.

Some squamous cell skin cancers may be more difficult to treat or can spread. This risk may depend on:

• The size or shape of the cancer
• What the cancer appears like when biopsy results are examined under a microscope
• Where the skin cancer is located
• Your other health problems

Possible Complications

• Local spread of the tumor
• Spread to other locations, including the internal organs

When to Contact a Medical Professional

Call for an appointment with your health care provider if you see the sore change in:

• Appearance
• Color
• Size
• Texture

Also call if you have pain, inflammation, bleeding, or itching of an existing skin sore.

Prevention

Reduce your sun exposure. Protect your skin from the sun by wearing hats, long-sleeved shirts, long skirts, or pants.

Sunlight is most intense between 10 a.m. and 4 p.m., so try to limit exposure during these hours.

Use high-quality sunscreens, preferably with sun protection factor (SPF) ratings of at least 30 that protect against both UVA and UVB sunlight. Apply the sunscreen at least 30 minutes before going outside and reapply frequently. Use a sunscreen throughout the year, even during the winter. Use a waterproof formula.

Other important facts to help avoid too much sun exposure:

• Avoid surfaces that reflect light, such as water, sand, concrete, and white-painted areas.
• The dangers are greater closer to the start of summer.
• Skin burns faster at higher altitudes.
• Avoid sun lamps, tanning beds, and tanning salons.

Examine the skin regularly for any new suspicious growths or changes in an existing skin sore. A new growth that forms an ulcer or is slow to heal is suspicious.

Suspicious changes in an existing growth include:

• A change in color, size, texture, or appearance
• Development of pain, inflammation, bleeding, or itching

Alternative Names

Cancer - skin - squamous cell; Skin cancer - squamous cell; Nonmelanoma skin cancer - squamous cell; NMSC - squamous cell