What Is Skin Cancer?
Skin cancer starts in the cells of the skin. Some other types of cancer start in other parts of the body and can spread to the skin, but these are not skin cancers.
There are 3 main types of skin cancers:
- Basal cell skin cancers (basal cell carcinomas)
- Squamous cell skin cancers (squamous cell carcinomas)
Basal and squamous cell cancers
Basal and squamous cell skin cancers are by far the most common cancers of the skin. Both are found mainly on parts of the body exposed to the sun, such as the head and neck. These cancers are strongly related to a person’s sun exposure.
Basal and squamous cell cancers are much less likely than melanomas to spread to other parts of the body and become life threatening. Still, it’s important to find and treat them early. If left alone, they can grow larger and invade nearby tissues and organs, causing scarring, deformity, or even loss of function in some parts of the body. Some of these cancers (especially squamous cell cancers) can spread if not treated, and in some cases they can even be fatal.
These cancers are discussed in more detail in Skin Cancer: Basal and Squamous Cell.
Melanomas are cancers that develop from melanocytes, the cells that make the brown pigment that gives skin its color. Melanocytes can also form benign (non-cancerous) growths called moles. (Your doctor might call the mole a nevus.)
Melanomas can occur anywhere on the body, but are more likely to start in certain areas. The trunk (chest and back) is the most common place in men. In women, the legs are the most common site. The neck and face are other common places for melanoma to start.
Melanomas are not as common as basal cell and squamous cell skin cancers, but they can be far more serious. Like basal cell and squamous cell cancers, melanoma is almost always curable in its early stages. But if left alone, melanoma is much more likely to spread to other parts of the body, where it can be very hard to treat.
Melanomas are discussed in more detail in Melanoma Skin Cancer.
Other skin cancers
There are many other types of skin cancers as well, but they are much less common:
- Merkel cell carcinoma
- Kaposi sarcoma
- Cutaneous (skin) lymphoma
- Skin adnexal tumors (tumors that start in hair follicles or sweat and oil glands)
- Various types of sarcomas
Together, these types account for less than 1% of all skin cancers.
It’s important for doctors to tell the types of skin cancer apart, because they are treated differently. It’s also important for you to know what skin cancers look like. This can help you find them at the earliest possible stage, when they are cured most easily.
Last Medical Review: March 19, 2015 Last Revised: July 26, 2016
- Skin Cancer Prevention and Early Detection
- What Is Skin Cancer?
- What Is Ultraviolet (UV) Radiation?
- Are Some People More Likely to Get Skin Damage from the Sun?
- How Do I Protect Myself from UV Rays?
- What About Tanning Pills and Other Tanning Products?
- Skin Exams
- What Should I Look for on a Skin Self-Exam?
- What If I Find Something Suspicious on a Skin Exam?
- Additional Resources
- References: Skin Cancer Prevention and Early Detection