What Is Basal Cell Carcinoma?

Basal cell carcinoma (BCC) is skin cancer that starts in the lowest part of the epidermis. It can produce shiny lesions on the skin that can be (but are not always) discolored. Basal cell carcinoma accounts for about 80% of all non-melanoma skin cancer cases worldwide, and skin damage from UV light (sunlight, tanning beds) is one of the leading causes.

A biopsy is the most definitive way to verify a basal cell carcinoma diagnosis, and surgical removal of the cancer is usually recommended. A commitment to prevention, of course, is critical when it comes to BCC and all forms of skin cancer.

Basal Cell Carcinoma Types and Symptoms

A basal cell lesion is often described as a pearly papule because it has a slight shine. These papules are elevated (sometimes very slightly) above the surface of the skin and are generally the same color or slightly lighter than the surrounding skin.

Different symptoms and features may develop in some cases, including:

  • Telangiectasias: These small dilated blood vessels can form in areas affected by BCC. These lesions appear pink, red, or purplish.
  • Discoloration: The cancerous areas on the skin can appear dark or brownish due to the presence of dead cells.
  • Itchiness around the lesion
  • Lesion that looks like a persistent, non-healing wound

BCC lesions can appear suddenly. They may start at a size of 1 centimeter (cm) and continue to grow in size after they initially appear, becoming more noticeable with time.

Basal cell carcinoma lesions usually appear on areas of the body that have been exposed to sunlight, especially high levels of sunlight, including the face, ears, arms, legs, back, and abdomen. BCC can also occur in areas that aren't exposed to UV at all, such as the scalp, though this is not common.

This photo contains content that some people may find graphic or disturbing.

Basal cell carcinoma affecting the ear
DermNet / CC BY-NC-ND 

Variations

Basal cell carcinoma lesions can be categorized into several different types, each of which has differences when it comes to appearance.

  • Nodular: About 60% to 80% of BCCs are nodular. They start out as flat, well-defined lesions, then often become small bumps that eventually collapse in the middle, leaving a raised ring on the border. Most nodular BCCs are on the face and can be disfiguring if not treated promptly.
  • Pigmented: Pigmented BCCs are similar to the nodular type, but they can contain brown or black spots, which can give them an appearance that resembles certain types of melanoma.
  • Fibrosing or sclerotic: These BCCs are usually found on the face and look similar to scars. They are usually firm, ill-defined at the border, flat or slightly depressed, and yellowish in color. The surface tends to be smooth and shiny.
  • Superficial: This type comprises about 15% of BCCs. They spread outward from a red, well-defined, scaly patch and are most commonly found on the trunk and limbs. They are easily confused with psoriasis or eczema.
  • Fibroepithelioma of pinkus: This is a rare type of BCC. It tends to be a smooth, elevated, small nodule found on the back, extremities, groin, or sole of the foot. As those are not sun-exposed areas, this is probably not sun-related.

Complications

If basal cell carcinoma is left untreated, the lesions can grow and may eventually ulcerate (break through the skin) or damage the surrounding tissue or bone.

While it is rare, there are individuals who have lost an eye, nose, or ear due to untreated BCC.

The cancer can spread (metastasize) to other regions of the body, potentially causing serious health problems, though this is not common.

Causes

Like other types of cancer, BCC is caused by mutations, which are changes in the molecular structure of a cell's DNA. Several genetic mutations have been identified in association with basal cell carcinoma, including alterations in the PTCH1, PTCH2, SMO, PTPN14, LATS1, TERT, and DPH3-OXNAD1 genes.

However, the genetic changes in BCC aren't inherited. The cellular damage caused by ultraviolet (UV) light exposure is what results in DNA alterations that predispose someone to skin cancer. Notably, it can take 10 to 20 years after the causative UV light exposure for basal cell carcinoma to develop.

Some of the BCC-associated DNA alterations that occur can encourage cancer cells to proliferate, and some of these changes stand in the way of your body's ability to suppress tumor cell growth. Scientists continue to research exactly how damaged DNA leads to skin cancers.

Other types of skin cancer, such as squamous cell carcinoma, are more closely correlated with UV light exposure than BCC is. That, however, should not discount the role ultraviolet light plays in your risk of basal cell carcinoma.

UVA and UVB Light

UVA and UVB rays have different wavelengths, 280 to 315 nanometers (nm) and 315 to 400 nm, respectively. This means that UVA light penetrates deeper into your skin, though both can lead to skin damage that manifests as a tan, sunburn, or, eventually, skin cancer.

Excessive exposure to ultraviolet light can come from the sun or use of tanning salons. Outdoor exposure to each type of UV ray depends on the weather conditions and time of day. For example, while you will have exposure to them when it's sunny out, UVA rays penetrate more in cloudy weather.

Sunblock can help protect your skin, but UVA and UVB light rays can penetrate sunscreens and sunblock too. That means that prolonged exposure, even with sunblock still exposes your skin to the harmful effects.

Risk Factors

More than 4 million people are diagnosed with BCC each year in the United States. While this type of cancer typically begins during middle-age or beyond, it can also affect young adults. In fact, experts warn that BCC is affecting people at younger and younger ages.

Certain risk factors put you at greater risk for basal cell carcinoma:

  • Race: White people—especially those with blue eyes, a fair complexion, and red, blond, or light brown hair—have the highest risk of BCC. (African-Americans, Asians, and Hispanics can develop this type of cancer, but not commonly.)
  • Location: Living in a state that is closer to the equator, such as Florida
  • A history of sunburns during childhood: Not only does this raise the risk of you developing basal cell carcinoma, but doing so at a younger age.

Compared with whites, blacks have a decreased risk of BCC on UV light-exposed skin areas, but the same incidence of BCC on the covered skin. Having darker skin does not mean that you are protected from basal cell carcinoma—or any type of skin cancer, for that matter.

Diagnosis

Your doctor may recognize your skin lesion as BCC (and classify it as a certain type) based on appearance, but a biopsy must be done to confirm the diagnosis.

A skin biopsy is a removal of skin tissue for examination under a microscope. There are several types of skin biopsies. The right procedure for you depends on a few factors, including whether the lesion is raised above your skin.

  • Shave biopsy: Your doctor collects a sample of your tissue by using a thin surgical blade to shave off the top layers of skin. This is the most common biopsy method for diagnosing BCC.
  • Punch biopsy: This uses a round, small device that functions somewhat like a cookie-cutter. It is used to take a deeper skin sample.
  • Lymph node biopsy: If there is concern that your cancer may have spread to a nearby lymph node, your doctor may take a sample of tissue from the lymph node for examination.

Tumor staging is a classification used to describe the size of a tumor and how much it has spread. The grading of a tumor describes how fast-growing the cells are.

Your physical examination and biopsy are both used for tumor staging and grading.

Treatment

Your treatment depends on the type, extent, and location of your lesion(s). Although BCC doesn't typically spread to distant organs, the lesions can eventually cause disfigurement and should be removed as soon as possible.

Methods commonly used to treat BCC include:

  • Curettage and electrodesiccation: This procedure involves scraping the tumor and electrically burning it to remove the cancer cells.
  • Mohs surgery (micrographic surgery): This is a specialized procedure in which your doctor will remove the area that appears cancerous and send it for a microscopic evaluation to confirm whether all of the cancer has been removed. You may need to have a deeper area surgically removed until it is confirmed that the whole cancerous area has been resected.
  • Surgical excision (removal): Your whole lesion, and possibly metastasis, can be removed surgically.
  • Aldara (imiquimod) is a topical cream approved for treatment of BCC. It peels away the cancerous lesion.
  • Radiation therapy is an option for some tumors, especially if they are located in an area that is not optimal for surgery, such as the ear.

The treatment required to remove basal cell carcinomas is much simpler and less likely to cause significant scarring when they are small.

Lesions that have spread need to be treated with oral targeted agents specifically designed for treatment of BCC. The two agents currently approved by FDA for treatment of BCC are Erivedge (vismodegib) and Odomzo (sonidegib).

Prevention

Investing in prevent strategies is so important when it comes to skin cancers. It is best to completely avoid using tanning beds/booths, and to be mindful of the amount of sun you're getting (as well as to be protected when you are outdoors).

Regular skin self-exams can help you catch any lesions at an early stage before they grow or spread.

Safe Sun Exposure

You need to protect yourself from UV rays whether it's bright and sunny or cloudy.

If you have to work outside in the hot sun, dress in clothing that covers your skin and wear a hat if possible. It isn't always easy to find clothes that covers your skin without overheating you, so it's worth planning ahead. You might even look for clothing made of fabrics with an SPF rating.

If you can adjust your schedule, try to go out when the sun isn't so bright and make sure you spend at least some of your time in the shade.

Consider using a beach umbrella or sitting under a canopy if you are dining at an outdoor cafe.

Sunscreen

There are a number of features to pay attention to when selecting a sunscreen. Some points to keep in mind:

  • Most sunscreens protect from UVB light, but only "broad-spectrum" products also protect from UVA light.
  • The higher the sun protection factor (SPF), the more protection a product offers.
  • Not all sunscreens are waterproof or water-resistant. If you tend to sweat a lot or know you'll be swimming, be sure to check that yours is.
  • Products containing zinc are usually thicker and more visible, making it easier to see when they've washed off. But if that is undesirable from an aesthetics perspective, choose a product that absorbs into the skin. The best product is the one you won't hesitate using.

Keep in mind that SPF doesn't necessarily correlate with whether a product is broad-spectrum or water-resistant or not. So you have to look at each of these features individually.

Maintain Skin Health

Get a medical assessment of any dark spots, shiny spots, or any areas with color or texture changes before they grow or become serious.

You can have regularly scheduled appointments with a dermatologist if you are at risk of BCC, and you can also make an appointment when you notice concerning lesions on your skin.

A Word From Verywell

Basal cell carcinoma is the most common—but also one of the most curable—of all cancers. However, even after effective treatment, a person with a history of BCC has a greater likelihood of developing it again than someone with no history of the disease. You need to be especially vigilant about prevention if you have a history of BCC.

Keep in mind that it isn't healthy to completely avoid the sun—not only is sunlight a source of vitamin D, a lack of sunlight is associated with seasonal affective disorder. Moderation is the key.

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