Basal cell carcinoma

Basal cell carcinoma is a type of skin cancer. Basal cell carcinoma begins in the skin cells called basal cells. The basal cells make new skin cells as old ones die off.

Basal cell carcinoma often looks like a slightly transparent bump on the skin, though it can take other forms. Basal cell carcinoma occurs most often on areas of the skin that get a lot of sun, such as the face and neck.

Most basal cell carcinomas are caused by exposure to light from the sun. Using sunscreen and other sun protection methods can help lower your chances of getting basal cell carcinoma.

Basal cell carcinoma on white skin

Basal cell carcinoma is a type of skin cancer that most often develops on areas of skin exposed to the sun, such as the face. On white skin, basal cell carcinoma often looks like a bump that's skin-colored or pink.

Basal cell carcinoma on brown skin

Basal cell carcinoma is a type of skin cancer that most often develops on areas of skin exposed to the sun, such as the face. On brown and Black skin, basal cell carcinoma often looks like a bump that's brown or glossy black and has a rolled border.

Basal cell carcinoma usually occurs on parts of the body that get a lot of sun, especially the head and neck. Less often, basal cell carcinoma can develop on parts of the body usually protected from the sun, such as the genitals.

Basal cell carcinoma appears as a change in the skin, such as a growth or a sore that won't heal. These changes in the skin are called lesions. Lesions usually have one of the following characteristics:

• A shiny, skin-colored bump that's translucent, meaning you can see a bit through the surface. The bump can look pearly white or pink on white skin. On brown and Black skin, the bump often looks brown or glossy black. Tiny blood vessels might be visible, though they may be difficult to see on brown and Black skin. The bump may bleed and scab over.
• A brown, black or blue lesion, or a lesion with dark spots, with a slightly raised, translucent border.
• A flat, scaly patch with or without a raised edge. Over time, these patches can grow quite large.
• A white, waxy, scarlike lesion without a clearly defined border.

Make an appointment with a doctor or other healthcare professional if you see changes in the appearance of your skin, such as a new growth, a change in a previous growth or a returning sore.

Basal cell carcinoma starts in basal cells in the skin. Basal cells are found at the bottom of the outermost layer of skin, which is called the epidermis. Basal cells create new skin cells. As new skin cells form, they push older cells toward the skin's surface, where the old cells die and are sloughed off.

Most basal cell carcinomas are caused by exposure to light from the sun. The light that comes from the sun is a kind of ultraviolet light. This kind of light also can come from tanning beds and tanning lamps. Ultraviolet light contains radiation that changes the DNA inside the skin's basal cells. This can lead to basal cell carcinoma.

Not all basal cell carcinomas happen on skin that typically gets a lot of sun. This means something else also causes basal cell carcinomas. The cause is not always clear. But healthcare professionals have found some factors that increase the risk of basal cell carcinoma. These include having a weakened immune system and having a family history of skin cancer.

Basal cell carcinoma starts when the skin's basal cells develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA tells the cells to grow and multiply at a set rate. The DNA also tells the cells to die at a set time.

In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to grow and multiply quickly. Cancer cells can keep living when healthy cells would die. This causes too many cells.

The cancer cells can invade and destroy healthy body tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it's called metastatic cancer. Basal cell carcinoma can spread, but this is rare. Most basal cell carcinomas do not spread.

Where skin cancer develops

Skin cancer begins in the cells that make up the outer layer of the skin, called the epidermis. One type of skin cancer called basal cell carcinoma begins in the basal cells. Basal cells make skin cells that keep pushing older cells toward the surface. As new cells move up, they become squamous cells. Skin cancer that starts in the squamous cells is called squamous cell carcinoma of the skin. Melanoma, another type of skin cancer, happens in the pigment cells, called melanocytes.

Factors that increase the risk of basal cell carcinoma include:

• Chronic sun exposure. A lot of time spent in the sun or in commercial tanning beds increases the risk of basal cell carcinoma. The threat is greater if you live in a sunny or high-altitude location where ultraviolet radiation is stronger. Severe sunburns also increase your risk.
• Radiation therapy. Radiation therapy to treat acne or other skin conditions may increase the risk of basal cell carcinoma at previous treatment sites on the skin.
• Skin that sunburns easily. The risk of basal cell carcinoma is higher among people who have white skin, light-colored eyes, or red or blond hair.
• Increasing age. Basal cell carcinoma often takes decades to develop, so it's most common in older adults. But it also can affect younger adults and is becoming more common in people in their 20s and 30s.
• A personal or family history of skin cancer. If you've had basal cell carcinoma one or more times, you have a higher chance of developing it again. If you have a family history of skin cancer, you may have an increased risk of developing basal cell carcinoma.
• Medicines to control the immune system. Medicines that work by suppressing the immune system raise the risk of basal cell carcinomas significantly. Medicines that work in this way include those used after an organ transplant to prevent rejection.
• Exposure to arsenic. Arsenic is a toxic metal found widely in the environment that increases the risk of basal cell carcinoma and other cancers. Everyone is exposed to some arsenic because it occurs naturally. But people who drink contaminated well water or work with arsenic may be exposed to higher arsenic levels.
• Inherited syndromes that cause skin cancer. Certain rare genetic diseases can increase the risk of basal cell carcinoma. These diseases include nevoid basal cell carcinoma syndrome, also called Gorlin-Goltz syndrome, and xeroderma pigmentosum.

Complications of basal cell carcinoma can include:

• A risk of recurrence. Basal cell carcinomas often return, even after successful treatment.
• An increased risk of other types of skin cancer. A history of basal cell carcinoma also may raise the chance of developing other types of skin cancer, such as squamous cell carcinoma.
• Cancer that spreads beyond the skin. Very rarely, basal cell carcinoma can spread to nearby lymph nodes and other parts of the body, such as the bones and lungs.

Basal cell carcinoma and other skin cancers can be prevented by taking precautions. To lower the risk of skin cancer you can:

• Stay out of the sun during the middle of the day. For much of North America, the sun's rays are strongest between about 10 a.m. and 3 p.m. Plan outdoor activities at other times of the day. When outside, stay in shade as much as possible.
• Wear sunscreen year-round. Use a broad-spectrum sunscreen with an SPF of at least 30, even on cloudy days. Apply sunscreen generously. Apply again every two hours. Apply it more often if you're swimming or sweating.
• Wear protective clothing. Wear dark, tightly woven clothes that cover your arms and legs. Wear a wide-brimmed hat that shades your face and ears. Don't forget sunglasses.
• Don't use tanning beds. The lights in tanning beds give off ultraviolet light. Using tanning beds increases the risk of skin cancer.
• Check your skin often and report changes to your healthcare team. Look at your skin often for new growths. Look for changes in moles, freckles, bumps and birthmarks. Use mirrors to check your face, neck, ears and scalp.

  Look at your chest and trunk and the tops and undersides of your arms and hands. Look at the front and back of your legs and your feet. Look at the bottom of the feet and the spaces between your toes. Also check your genital area and between your buttocks.