Squamous cell carcinoma (SCC) is the second most common form of skin cancer, with over 250,000 new cases per year estimated in the United States. It arises in the squamous cells that compose most of the upper layer of the skin.

Most SCCs are not serious. When identified early and treated promptly, the future is bright. However, if overlooked, they are harder to treat and can cause disfigurement. While 96 to 97 percent of SCCs are localized, the small percentage of remaining cases can spread to distant organs and become life-threatening. The Skin Cancer Foundation website can provide more information on diagnosis and treatment options.


Most cases of squamous cell carcinoma are caused by chronic overexposure to the sun. Tumors appear most frequently on the sun-exposed face, neck, bald scalp, hands, shoulders, arms and back. The rim of the ear and the lower lip are especially vulnerable to these cancers.

SCCs may also occur where skin has suffered certain kinds of injury: burns, scars, long-standing sores, sites previously exposed to X-rays or certain chemicals (such as arsenic and petroleum by-products). In addition, chronic skin inflammation or medical conditions that suppress the immune system over an extended period of time may encourage development of the disease.

Occasionally, squamous cell carcinoma arises spontaneously on what appears to be normal, healthy, undamaged skin. Some researchers believe that a tendency to develop this cancer may be inherited.

Am I at Risk?

Anyone with a substantial history of sun exposure can develop squamous cell carcinoma but certain environmental and genetic factors can increase the potential for this disease.

Sun Exposure

Sunlight is responsible for over 90 percent of all skin cancers. Working primarily outdoors, living in an area that gets a lot of high intensity sunlight, and spending time in tanning booths all increase your exposure to UV rays and thus increase your risk for developing skin cancer, including squamous cell carcinoma.

Skin Type

People who have fair skin, light hair, and blue, green, or gray eyes are at highest risk. More than two thirds of the skin cancers that dark-skinned individuals develop are SCCs, usually arising on the sites of preexisting inflammatory skin conditions or burn injuries. It is still essential for them to practice sun protection.

Previous Skin Cancer

Anyone who has had a skin cancer of any type is at increased risk of developing another one.

Reduced Immunity

People with weakened immune systems due to excessive unprotected sun exposure, chemotherapy, organ transplantation, certain medications or illnesses such as HIV/AIDS are more likely to develop squamous cell carcinoma.

What to Look For

Squamous cell tumors are scaly, rough, crusty growths often on a red base. Occasionally, they will ulcerate, which means that the epidermis above the cancer is not intact.  Click here for photos on the Skin Cancer Foundation website.

Any bump or open sore in areas of chronic inflammation could be a squamous cell carcinoma. The surrounding skin often shows signs of sun damage, such as wrinkling, changes in pigmentation and loss of elasticity.


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