Skin Cancer: Basal Cell Carcinoma Diagnosis

  • Diagnosis

    Basal cell carcinoma is an extremely common form of skin cancer that is usually found in light-skinned populations who have had significant sun exposure. Of all skin cancers, basal cell carcinoma (BCC) is the most common. It is associated with sun exposure, and usually appears on the head or neck. Basal cell carcinoma is increasing in incidence in the US, possibly because more people are living longer. However, the incidence of BCC in young adults in their twenties and thirties is also increasing.

    BCC usually appears as a flat growth on the head or neck. It may appear red and look like an irritated patch of skin, or look like a pearly bump, a white or yellow scar-like lesion, or an open sore that never completely heals. Fortunately, it is almost always curable Figure 01. The lesions often appear translucent, and contain visible small blood vessels. They grow slowly and rarely spread to other parts of the body. However, untreated lesions can cause considerable damage due to extensive destructive growth patterns. Surgical removal of the lesions is the preferred treatment, although radiation and cryosurgery (which involves removal of the lesion by freezing) are common alternatives. The cure rate can approach 90% to 95% with appropriate treatment.

    Click to enlarge: Basal cell carcinoma

    Figure 01. Basal cell carcinoma

    If BCC is left untreated, its uncontrolled growth will destroy normal skin and invade bone and, in some cases, other vital structures. Fortunately, BCC is usually discovered before significant damage occurs, and is cured by surgical removal or destruction. In rare cases basal cell carcinoma spreads to distant organs. These cases call for aggressive surgical treatment.

    Like other skin cancers, BCC is predominantly caused by damage from sun exposure. Lesions arise from cells in the lowest layer of the epidermis and spread locally, destroying surrounding tissue Figure 02. The skin, the largest organ of the body, is composed of three layers. The topmost layer (epidermis) is where most skin cancers develop. Basal cell carcinoma arises from the epithelial cells, the cells that comprise most of the epidermis. Both radiation from the sun and artificial radiation contribute to BCC development. Most BCC is found on commonly sun-exposed areas (the face, ears, scalp, and neck) of older, light-skinned individuals.

    Click to enlarge: Skin anatomy

    Figure 02. Skin anatomy

    Other factors such as genetic predisoposition, trauma, chronic ulcers, burn scars, or some types of birthmarks may also lead to basal cell carcinoma, as evidenced by the fact that BCC can occur on parts of the body that are not exposed to the sun.

    Basal cell carcinoma has a variety of appearances. It typically forms a small, skin-colored bump with visible tiny blood vessels. It may present as a “pimple” that never resolves, or become an open sore that never completely heals Table 01. The majority of BCCs are found on the head and neck. BCC lesions are usually translucent or pink bumps containing small, red, spider-like blood vessels. They may or may not have distinct borders. The lesions usually enlarge slowly. Sometimes an open sore forms in the center, which scabs over and appears to heal, only to open up later. Basal cell carcinoma can also form larger, more superficial reddish lesions that resemble a localized rash. This superficial form more commonly occurs on the trunk. Some lesions contain brown or black pigment.

    Lesions may also develop on areas of the body that are protected from the sun, although this is not as common. There are types of BCC that grow “under” the skin and have a scar-like appearance.

    Table 1.   Basal Cell Carcinoma - What To Look For

    Typical lesions
    Translucent or pink bump
    Apparent blood vessels
    Successively opens, scabs, and temporarily heals
    Usually on head or neck
    Less common lesions
    Anywhere on body
    Darkly pigmented
    Reddish, rash-like

    Like all skin cancers, BCC is especially common in light-skinned people who have a history of excessive sun exposure or sunburns, and spend a lot of time in the sun. Basal cell carcinoma is considered to be a disease of Caucasian people. Individuals with fair skin, red or blond hair, and blue or green eyes are more likely to be affected. The condition is rarely found in African-Americans and other populations with dark skin. It usually occurs in older people, with its incidence increasing dramatically after age 40. There is no significant gender difference.

    For the most part, the risk of developing BCC is proportional to the amount of sun that one has been exposed to. It is believed that the majority of damaging sun exposure occurs in childhood and early adolescence. The incidence of skin cancer is rising dramatically in the U.S. In addition, more people are living in the sun belt and spending more time outside in recreational pursuits. Another possible cause is the depletion of the ozone layer, leading to increased levels of ultraviolet radiation reaching the earth.

    Other risk factors for BCC include inherited conditions as well as exposure to arsenic. Arsenic exposure is a hazard of certain occupations (e.g., glass manufacturing), is found in herbicides, and can contaminate drinking water. Arsenic exposure has been linked to the development of BCC. Gorlin's syndrome, or nevoid basal cell carcinoma syndrome, is a genetic disorder that affects skin cells' ability to repair the damaging effects of the sun. Individuals who have this condition develop multiple BCCs at an early age.

    People who have been diagnosed with BCC have an increased risk of developing an additional BCC in the next 5 to 10 years.

    Tissue from a suspected lesion must be examined microscopically to make a definitive diagnosis. A doctor will suspect basal cell carcinoma based on its characteristic appearance, but a biopsy and examination under a microscope is required to be certain of the diagnosis. Classification is important to determine the prognosis and best treatment options for this condition. There are several types of BCC that can be distinguished microscopically; these include nodular, superficial, and infiltrative subtypes. Classifying the subtype is important, as it helps direct treatment options and identify lesions with an increased risk of recurrence. The nodular subtype is the most common, and usually grows slowly. Infiltrative lesions are the most difficult to treat, and the most likely to behave aggressively.

    Protection from excessive sun exposure--especially though regular use of sunscreen with SPF 15 or higher, protective clothing, and avoiding the midday sun--is essential for reducing the risk of all types of skin cancer. Light-skinned individuals who burn easily should be especially cautious. The following precautions should be taken by everyone to guard against excessive exposure to UVA and UVB radiation.

    • Try to schedule time outdoors for sports and other recreational activities before 10am and after 4pm. By doing this you will avoid excessive exposure to UVB radiation. Clouds and haze do not significantly block harmful ultraviolet radiation.
    • When outdoors, wear clothes that cover as much skin as possible; such as lightweight, long-sleeved shirts, long pants, and a broad-brimmed hat.
    • Use particular care around reflective surfaces such as water, sand, concrete, and white-painted areas.
    • Everyone over 6 months of age should use a broad-spectrum sunscreen that protects from UVA and UVB rays, and has a skin protection factor (SPF) of at least 15. Apply to exposed skin twenty minutes before exposure and reapply every two hours. More frequent re-application may be necessary after exercise or water-related activities.
    • Sunscreen products that contain zinc oxide or titanium dioxide offer the best broad spectrum of protection.
    • There is no such thing as a “safe” or “healthy” tan. Avoid tanning booths and sun lamps as they are associated with development of skin cancer and promote premature aging of the skin.

    Check your skin regularly and have your doctor check your skin at your annual checkup. Experts recommend that individuals conduct a thorough screening of their own skin periodically. Having a partner check your back and other hard-to-see places is ideal. You can also use a hand-held mirror to check your back yourself. Consider drawing a map of your body, and indicate the location of moles, areas of discoloration, and other blemishes. Each month note if a new growth has developed, or if there has been any change in shape, color, or size of lesions. See your doctor if you have any questions or suspicions.

    At your annual checkup, ask your doctor to look at your skin, especially in areas you can't see. People with major risk factors, such as a history of significant sun exposure and a fair complexion with a history of burning easily, should be checked at least annually by a dermatologist.

  • Prevention and Screening

    Protection from excessive sun exposure--especially though regular use of sunscreen with SPF 15 or higher, protective clothing, and avoiding the midday sun--is essential for reducing the risk of all types of skin cancer. Light-skinned individuals who burn easily should be especially cautious. The following precautions should be taken by everyone to guard against excessive exposure to UVA and UVB radiation.

    • Try to schedule time outdoors for sports and other recreational activities before 10am and after 4pm. By doing this you will avoid excessive exposure to UVB radiation. Clouds and haze do not significantly block harmful ultraviolet radiation.
    • When outdoors, wear clothes that cover as much skin as possible; such as lightweight, long-sleeved shirts, long pants, and a broad-brimmed hat.
    • Use particular care around reflective surfaces such as water, sand, concrete, and white-painted areas.
    • Everyone over 6 months of age should use a broad-spectrum sunscreen that protects from UVA and UVB rays, and has a skin protection factor (SPF) of at least 15. Apply to exposed skin twenty minutes before exposure and reapply every two hours. More frequent re-application may be necessary after exercise or water-related activities.
    • Sunscreen products that contain zinc oxide or titanium dioxide offer the best broad spectrum of protection.
    • There is no such thing as a “safe” or “healthy” tan. Avoid tanning booths and sun lamps as they are associated with development of skin cancer and promote premature aging of the skin.

    Check your skin regularly and have your doctor check your skin at your annual checkup. Experts recommend that individuals conduct a thorough screening of their own skin periodically. Having a partner check your back and other hard-to-see places is ideal. You can also use a hand-held mirror to check your back yourself. Consider drawing a map of your body, and indicate the location of moles, areas of discoloration, and other blemishes. Each month note if a new growth has developed, or if there has been any change in shape, color, or size of lesions. See your doctor if you have any questions or suspicions.

    At your annual checkup, ask your doctor to look at your skin, especially in areas you can't see. People with major risk factors, such as a history of significant sun exposure and a fair complexion with a history of burning easily, should be checked at least annually by a dermatologist.

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