Skin cancer is a serious disease that can affect anyone at any age. It’s the most common cancer in the U.S. If found early, when it’s small and hasn’t spread, some of the more common types of skin cancer can often be cured. But some types of skin cancer can be life-threatening.

Talk with your healthcare provider about what you can do to help prevent skin cancer. Ask about regular skin exams as part of your routine physicals. You can also ask about doing monthly self-exams of your skin. If you see any changes in your skin, see your healthcare provider right away. 

Understanding the skin

The skin is made up of 3 layers: epidermis, dermis, and hypodermis

Epidermis

This is the thin outer layer of the skin. It’s the main barrier to the world outside our bodies. It’s made of 3 types of cells: squamous cells, basal cells, and melanocytes.

Squamous cells are flat cells in the outermost layer. They are always shedding off as new ones are forming.

Basal cells are round cells found just beneath the squamous cells at the base of the epidermis. They change into squamous cells as they get closer to the surface of the skin.

Melanocytes are scattered through the basal layer. They make melanin to give skin its color.

Dermis

This middle layer of skin is where blood and lymph vessels, hair follicles, oil and sweat glands, nerves, collagen are found. It supports the epidermis and it is a key part of wound healing. It also gives the skin flexibility and strength.

Hypodermis

This is the deepest layer of the skin. It’s made of fat, collagen, and blood vessels. It helps insulate the body, helps absorb shock, and protects the body from injury.

Skin cancer forms in the epidermis. It can start in the basal cells, squamous cells, or melanocytes.

Skin cancer can be grouped into two types: non-melanoma and melanoma.

The two most common types of non-melanoma skin cancer are basal cell carcinoma and squamous cell carcinoma.

Basal cell cancer

Basal cell cancer is the most common skin cancer. It starts in basal cells in the deepest part of the epidermis. It’s usually found on sun-exposed skin, like the face, ears, neck, trunk, or arms, but it can start anywhere.

These lesions vary in color and may be waxy, pearly, scaly, or scar-like. Tiny blood vessels can sometimes be seen through the lesion’s surface. These lesions can bleed easily and might not heal well. Nearly all basal cell cancers can be treated and cured if they’re found early.

Squamous cell cancer

Squamous cell cancer is the second most common type of skin cancer. It starts in flat cells called squamous cells. Lesions often form on the face, ears, neck, hands, or arms – places that get a lot of sun. The lesions are firm, red bumps or flat, scaly, crusty growths. They may be sores that keep healing and reopening.

Squamous cell carcinoma is more likely to grow and spread to other parts of the body than basal cell carcinoma, though this is rare. Most squamous cell carcinoma is found early enough to be treated and cured.

Actinic keratosis

Actinic keratosis (AK) is not skin cancer. It’s a common, pre-cancer skin change that can turn into squamous cell skin cancer if not treated.

AK lesions tend to be found on sun-exposed parts of the body. They can be pink, reddish-brown, or skin-colored. These lesions are often small, raised, scaly, and rough, like sandpaper. In some cases, AK lesions hurt. Most people with them have more than one lesion. Getting early treatment for AK almost always cures the lesions.

Melanoma

Melanoma is a less common, but much more dangerous kind of skin cancer. It starts in skin cells called melanocytes. It’s much more likely to grow and spread than basal or squamous cell cancers. Finding and treating it early is key.

It’s often not easy to tell where a melanoma lesion’s borders are. It’s often brown or black, but may be a mix of colors with pink, tan, or white. The shape and size of melanoma lesions tend to differ from one side to the other. Melanoma is most often found on sun exposed skin, but can start anywhere, like the genitals, mouth, palms of hands, bottoms of feet, and under the nails.

Less common skin cancers

There are other types of skin cancer, too. These include Merkel cell cancer, Kaposi sarcoma, and skin (cutaneous) lymphomas, but these cancers are very rare.