Skin cancer
Key points
- Skin cancer is the uncontrolled growth of skin cells.
- The outer layer of skin, the epidermis, is made up of different types of cells.
- They can be small, shiny, or waxy; scaly or rough; firm and red; crusty or bleeding; or have other features.
- Different types of skin cancer require different treatment approaches.
Alternative names
Cancer - skin
Definition
Skin cancer is the uncontrolled growth of skin cells. If left unchecked, these cancer cells can spread from the skin into other tissues and organs.
There are different types of skin cancer. Basal cell carncinoma is the most common. Melanoma is less common, but more dangerous.
Causes, incidence, and risk factors
The outer layer of skin, the epidermis, is made up of different types of cells. Skin cancers are classified by the types of epidermal cells involved:
- Basal cell carcinoma develops from abnormal growth of the cells in the lowest layer of the epidermis and is the most common type of skin cancer.
- Squamous cell carcinoma involves changes in the squamous cells, found in the middle layer of the epidermis.
- Melanoma occurs in the melanocytes (cells that produce pigment) and is less common than squamous or basal cell carcinoma - but more dangerous. It is the leading cause of death from skin disease.
Skin cancers are sometimes classified as either melanoma or nonmelanoma. Basal cell carcinoma and squamous cell carcinoma are the most common nonmelanoma skin cancers. Other nonmelanoma skin cancers are Kaposi's sarcoma, Merkel cell carcinoma, and cutaneous lymphoma.
Skin cancer is the most common form of cancer in the Unites States. Known risk factors for skin cancer include the following:
- Complexion. Skin cancers are more common in people with light-colored skin, hair, and eyes.
- Genetics. Having a family history of melanoma increases the risk of developing this cancer.
- Age. Nonmelanoma skin cancers are more common after age 40.
- Sun exposure and sunburn. Most skin cancers occur on areas of the skin that are regularly exposed to sunlight or other ultraviolet radiation. This is considered the primary cause of all skin cancers.
Skin cancer can develop in anyone, not only people with these risk factors. Young, healthy people - even those with with dark skin, hair, and eyes - can develop skin cancer.
Symptoms
Skin cancers can have many different appearances. They can be small, shiny, or waxy; scaly or rough; firm and red; crusty or bleeding; or have other features. Therefore, anything suspicious should be looked at by a physician. See the individual articles on specific skin cancers for more information.
Here are some features to look for:
Written and revised by
David Cohen, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.