What Is Skin Cancer?

Skin cancer occurs when abnormal skin cells grow out of control. It is the most common form of cancer in the United States, with more than two million people diagnosed with skin cancer annually. In fact, between 40 and 50 percent of Americans who live to age 65 will develop skin cancer at some point in their lives.

Skin cancer is the most curable cancer when it's diagnosed and treated early. Untreated skin cancer can lead to disfigurement and even death.

Approximately 13 million Americans have a history of non-melanoma skin cancer, typically diagnosed as basal cell carcinoma or squamous cell carcinoma, both of which are curable.

There are three main types of skin cancer:

  • Basal cell carcinoma: Basal cell cancer usually starts as a small pearly bump, dark spot or scaly red patch that doesn't go away. Although it is the least risky form of skin cancer, it can spread to deeper layers of skin or bone if left untreated. This type of skin cancer often develops in areas exposed to the sun, such as the head, face, neck, arms and hands.
  • Squamous cell carcinoma: The second most common form of skin cancer, squamous cell cancer resembles a rough and crusty dome-shaped bump or red patch. They may itch and bleed easily when scraped. Like basal cell cancer, it often starts in areas of skin exposed to the sun, such as the face, head, neck, arms and hands. It can also start in other parts of the body, such as skin in the genital area.
  • Melanoma: The most serious and least common type of skin cancer, melanoma almost always begins as a mole. Malignant melanoma is aggressive and tends to spread to other parts of the body.

Kaposi sarcoma

A different type of cancer that impacts the skin, Kaposi sarcoma starts in the skin's blood vessels and develops in two forms. The slow-growing form usually starts as a purple or dark-brown, flat or raised, area on the lower leg. The more aggressive, faster-spreading form starts as a pink, red or purple, round or oval, spot anywhere on the body, and may affect internal organs.

Kaposi sarcoma often impacts older people of European, Italian or Middle Eastern descent; children and young men in African nations near the equator; people receiving immune-suppressing drugs, such as those administered after organ transplants; and in people with the AIDS virus.

Cutaneous Lymphoma

Cutaneous T-cell lymphoma is a disease caused when T-lymphocytes become malignant and affect the skin. T-lymphocytes are the infection-fighting white blood cells in the lymphatic system that kill harmful bacteria in the body, among other things.

Cutaneous lymphomas are rare, yet the incidence has doubled over the past 25 years (4500 new patients per year).

Cutaneous T-cell lymphoma usually is a slow-growing cancer that often develops over many years. The two most common types of cutaneous T-cell lymphoma are mycosis fungoides and the Sezary Syndrome.

Learn more about cutaneous lymphoma.