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Types of Skin Cancer

Skin cancer is generally categorized into four different types, some more serious than others. The four main types are Melanoma, Basal cell carcinoma, Squamous cell carcinoma, and Merkel cell carcinoma.

Medically reviewed by Susan Kerrigan, MD and Marianne Madsen

Skin cancer is the most common type of cancer, diagnosed in over 3 million Americans per year. Most skin cancers are also very treatable, provided they’re found early. Skin cancer can be caused by various factors, including exposure to sunlight and artificial tanning. White people, males, and people with weakened immune systems are most at risk for skin cancer.

What are the different types of skin cancer?

Skin cancer is generally categorized into four different types, some more serious than others. A few rare skin cancers exist as well.

Melanoma. Melanoma affects the melanin-producing cells in the skin called melanocytes. It can develop anywhere on the skin, but it mostly forms on parts of the body that have been exposed to the sun. It is considered to be the most deadly type of skin cancer. In fact, most of the skin cancer deaths in the United States are from melanoma.

Melanoma is diagnosed by looking at moles or growths on the skin that have an irregular appearance. Moles that are asymmetrical, strangely colored, or unusually large may be an indicator of melanoma.

Basal cell carcinoma. Basal cell carcinoma is a type of skin cancer that affects the basal cells, found in the lower part of the epidermis. This cancer typically appears in the head and neck area and is caused by frequent exposure to the sun’s rays. People who underwent radiation therapy in childhood are also more at risk for this type of cancer.

Basal cell carcinoma looks like a sore, scar, growth, or red patch. It makes up 80% of skin cancers.

Squamous cell carcinoma. Like basal cell carcinoma, squamous cell carcinoma also develops on the outer layer of the skin but targets the squamous cells (cells that are nearer the surface) rather than the basal cells. This cancer is also primarily caused by exposure to the sun. Less often, it can develop on burned skin or skin that has been exposed to x-rays.

Squamous cell carcinoma spreads faster than basal cell carcinoma, which is why it’s vital to detect and treat it early. It looks like a growth, red patch, or open sore. About 20% of skin cancer cases are squamous cell carcinomas.

Merkel cell carcinoma. This type of cancer, which originates in the Merkel cells beneath the skin, is rare (only 3,000 cases per year) and spreads quickly. It’s most commonly found in the head and neck area. What causes it is not clear, but it’s known that the elderly are most at risk. Risk factors for other skin cancers can also increase your chances of developing Merkel cell carcinoma. Merkel cell carcinoma looks like a red or skin-colored bump or pimple.

Since the warning signs of skin cancer can vary depending on type, you should always see a doctor if you have a suspicious-looking spot anywhere on your body. An early diagnosis of skin cancer can save your life.