What is skin cancer?
Skin cancer is a type of cancer that begins in the cells of the skin. It occurs when skin cells grow abnormally and uncontrollably, often due to damage caused by ultraviolet (UV) radiation from the sun or tanning beds.
At Penn Medicine, our experienced specialists work together in diagnosing, treating, and researching all types of skin cancers. Our unique approach provides better outcomes and gives you access to the most advanced treatment, surgical techniques, and clinical trials available.
Skin cancer types
There are several types of skin cancer, each with distinct characteristics, diagnosing practices, and treatment options.
Basal cell carcinoma is the most common type of skin cancer in the United States. It develops in the outer layer of your skin. It usually looks like a shiny bump or a pinkish patch on your skin on places that get a lot of sun like your face, ears, neck, or shoulders. It grows slowly and doesn’t usually spread to other parts of your body, but it can cause problems if not treated, like damage to surrounding tissues.
Squamous cell carcinoma is the second-most common type of skin cancer in the United States. It can develop in several parts of the body: the outer layer of the skin, the surface lining of the head and neck, and the lining of the genitals. It typically develops as a red, scaly patch or a sore that fails to heal. If left untreated, it can grow and spread to other parts of the body.
Melanoma of the skin is the third-most common type of skin cancer in the United States. It can occur anywhere on the body, but most commonly develops in the pigment-producing cells on the skin. It often appears as a new spot on the skin that can be black, brown, pink, purple, or the same color as your skin, but it can also appear as changes to an existing mole. In addition to the skin, melanoma can grow in the eye or mucosal membranes such as the nose or mouth. It’s considered the most serious type of skin cancer because it can spread to other parts of the body.
Merkel cell carcinoma is a rare form of skin cancer. It starts in the Merkel cells, found at the base of the epidermis, which is the outer layer of your skin. It often appears as a fast-growing, painless nodule on the skin and is more likely to spread to other parts of the body.
Less common cancers that can develop on the skin include angiosarcoma, certain types of lymphoma like cutaneous B-cell lymphoma and cutaneous T-cell lymphoma, dermatofibrosarcoma protuberans, and sebaceous carcinoma.
Skin cancer symptoms
Skin cancer signs and symptoms can vary but may include:
- A bump or nodule with small, visible blood vessels
- A lump in the throat, mouth, or neck
- A new mole or growth
- Changes in existing moles, growths, or freckles
- Flat, scaly areas that may be red or brown and itchy or painful
- Numbness, tingling, or itching on the lips, mouth, or genitals
- Pearly or waxy bumps that are often flesh-colored, white, or pink
- Persistent, non-healing sores that may bleed, ooze, or crust over
- Pink or red growths with a slightly raised, rolled edge and a lower area in the center
- Sores that heal and then come back
- White or yellowish areas that resemble a scar with poorly defined borders
It’s important to note that not all skin changes or sores are cancerous. However, any concerning or persistent symptoms should be evaluated by your doctor. Early detection and treatment can significantly improve your outcomes.
Identifying the signs of skin cancer: The ABCDE method
The American Academy of Dermatology designed the ABCDE method to remember the signs of skin cancer. It stands for:
- Asymmetry: One half of the mole doesn’t match the other.
- Border: The mole’s edges are irregular, blurred, or poorly defined.
- Color: The color of the mole is not uniform. It may include shades of brown, black, tan, red, white, or blue.
- Diameter: The mole is greater than 6 millimeters, about the size of a pea. However, some skin cancers can be smaller.
- Evolving: The spot changes in size, shape, color, or in other ways over time, or new symptoms such as itching, tenderness, or bleeding begin.
Regular skin self-exams and professional skin screenings are essential for early detection and treatment. If you notice any suspicious changes on your skin, contact your Penn Medicine dermatologist immediately.
Skin cancer causes, risk factors, and prevention
Skin cancer is primarily caused by damage to the DNA in skin cells. The main skin cancer risk factors that contribute to this damage include:
- Sun exposure: The most significant cause of skin cancer is prolonged and unprotected exposure to the sun’s UV rays. Both UVA and UVB rays can damage the DNA in skin cells, leading to mutations that can cause cancer.
- Tanning beds: Artificial sources of UV radiation, such as tanning beds and sunlamps, also significantly increase the risk of developing skin cancer.
- Family history: A family history of skin cancer can increase your risk. Certain genetic conditions, such as xeroderma pigmentosum, which reduces the skin’s ability to repair DNA damage, can also elevate the risk.
- Fair skin: People with fair skin, light hair, and light eyes have less melanin, which provides some protection against UV radiation. This makes them more susceptible to skin damage and subsequent skin cancer.
- Age: The risk of skin cancer increases with age due to exposure to UV radiation over time.
- Immune system suppression: People with weakened immune systems, such as those who have had organ transplants and are taking immunosuppressive drugs, have a higher risk of developing skin cancer.
- Exposure to carcinogens: Certain chemicals, such as arsenic, coal tar, and some types of oil, can increase the risk of skin cancer with long-term exposure.
- Previous skin cancer: Having had skin cancer previously increases the likelihood of developing it again.
- Radiation therapy: Previous treatment with radiation therapy, particularly if it was directed at the skin, can increase the risk of skin cancer in the treated area.
- Human papillomavirus (HPV): Certain strains of HPV have been associated with an increased risk of skin cancers, particularly squamous cell carcinoma.
Understanding these risk factors can help in taking preventive measures such as avoiding excessive sun exposure, using sunscreen, and wearing protective clothing to reduce the risk of developing skin cancer. Regular skin checks and monitoring for any changes in the skin can also help in early detection and treatment.
Rated “exceptional” by The National Cancer Institute
Penn Medicine’s Abramson Cancer Center is a world leader in cancer research, patient care, and education. Our status as a national leader in cancer care is reflected in our continuous designation as a Comprehensive Cancer Center by the National Cancer Institute (NCI) since 1973, one of 7 such centers in the United States. The ACC is also a member of the National Comprehensive Cancer Network, one of a select few cancer centers in the U.S., that are working to promote equitable access to high-quality, advanced cancer care.
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