Skin cancer is the most
common cancer and will affect one in five Americans during their lifetime. It
occurs when abnormal skin cells grow out of control. Usually, these abnormal
cells arise when ultraviolet light from the sun or tanning beds damages their
DNA. Skin cancer is categorized based on the type of cell where the abnormality
occurs. Here’s a summary of the most common types of skin cancer and what they
1. Understanding Your Skin
Your skin consists of three layers—the epidermis,
dermis and subcutis. Most skin cancers occur in the epidermal layer. Within the
epidermis, skin cells are continually dividing and producing new skin cells at
the base or basal level of the epidermis. These skin cells push up through the
epidermis, flatten into squamous cells, and are eventually sloughed off as dead
skin. Your epidermis also contains melanocytes—cells that produce melanin, the
pigment that colors skin and hair.
2. Actinic Keratosis
Actinic keratosis (AK) is a common
precancerous skin condition, affecting more than 58 million Americans. AK is
usually a rough-textured, scaly, or crusty patch of skin. It’s often felt
before it’s seen. AK may eventually become elevated and resemble a wart. Left
untreated, AK can develop into a squamous cell carcinoma. This has led some
health experts to conclude that AK is actually a very early form of squamous
cell skin cancer.
3. Basal Cell Carcinoma (BCC)
Basal cell carcinoma (BCC) is the most
common form of skin cancer. It arises from cells in the base of the epidermis. Basal
epidermal cells are keratinocytes, which produce keratin—the protein that strengthens
hair, nails and skin. BCC can look like open sores, red patches, or pink,
pearly or shiny growths, bumps, or scars. Left untreated, BCC rarely spreads to
other areas, but can invade and disfigure nearby bone, muscle, and other tissues.
4. Squamous Cell Carcinoma (SCC)
Squamous cell carcinoma (SCC) is the
second most common type of skin cancer. It arises from squamous cells, which
make up most of the epidermis. Squamous epidermal cells are also keratinocytes,
the most common type of skin cell. SCC can look like scaly or crusty patches,
open sores, or elevated wart-like growths. SCC is more likely than BCC to grow
and spread, which can be disfiguring and life threatening in some cases.
While not as common as BCC or SCC, melanoma
is the most dangerous and aggressive form of skin cancer. Arising from
melanocytes, melanoma can look like a mole and some develop within an existing
mole. Most melanomas are either brown or black. However, melanomas can also be
multicolored, speckled, skin-colored, pink, red, purple, blue, or white. They
are also usually larger than 6 mm in diameter and asymmetrical with an uneven
border. We show a representative photo here, but this is just an example.
Discuss any and all strange or suspicious areas on your skin with a
dermatologist. Without proper treatment, melanoma can be fatal.
Looking at and thinking
about skin cancer can be unsettling. The good news is that skin cancer, even
melanoma, usually responds well to treatment when it is caught early. That’s
why it is so important to know your body and perform skin self-exams on a
regular basis. If you’ve had skin cancer or you have a high risk of developing
it, talk to your dermatologist about screenings. Find out how often you should
have a complete skin exam. And when in doubt, have it checked out!
Healthgrades would like to
thank Dr. Marcus Goodman for his contributions to this content. Dr. Goodman is
a board-certified dermatologist, Fellow of the American Osteopathic College of
Dermatology, and Diplomat of the American Osteopathic Board of Dermatology. He
also serves as an associate editor for the Journal
of the American Osteopathic College of Dermatology and as Clinical Associate
Professor at PCOM - Georgia Campus, Suwanee, GA. Visit Dr. Goodman at www.goodmandermatology.com.