Cancer is out-of-control cell growth in your body. This cancerous growth can happen in almost any body cells. Likewise, skin cancer starts when skin cells grow uncontrollably.
Types of Skin Cells
You have three main types of skin cells in your skin’s top layer, called the epidermis. These three types of epidermis skin cells include:
- Squamous Cells – Flat cells in your epidermis outer part, constantly being shed to make way for newly formed skin cells.
- Basal Cells – Skin cells in your lower epidermis, the basal cell layer, which constantly divide to form new skin cells. These basal cells move up in the layers of your epidermis and flatten to become squamous cells.
- Melanocytes – Skin cells producing melanin that gives your skin its color. Melanin provides natural sunscreen, protecting the more sensitive deeper layers of skin from the sun’s harmful effects. Your suntan occurs when your melanocytes make more pigment due to sun exposure.
Your epidermis sits above deeper layers of skin, separated from those layers by a membrane. This membrane is the basement membrane. Advanced skin cancer grows through this skin membrane into deeper layers of skin.
Common Skin Cancer Types
The most common skin cancer types include:
- Basal Cell Carcinoma
The most common skin cancer type, basal cell carcinoma accounts for 80 percent of skin cancer cases. These cells look like basal layer skin cells under a microscope. These cancers occur on areas of skin exposed to the sun, such as the head and neck. These cancers rarely spread to other body regions and grow slowly. Left untreated, they can grow into bone or tissues under your skin, however.
- Squamous Cell Carcinoma
About 20 percent of skin cancers are squamous cell carcinomas. These look like abnormal versions of squamous cells of the skin’s outer layer. These cancers also appear on sun-exposed areas like your face, ears, lips, neck and backs of your hands. They also commonly affect scars or chronic skin sores. Sometimes these cancers form in genital area skin. Squamous cell carcinomas sometimes grow into deeper skin layers and spread to other regions of the body.
Keratoacanthomas are tumors shaped like domes. They occur on sun-exposed skin, often starting out growing rapidly then slowing in growth. Many of these skin cancers shrink or disappear on their own without treatment. But some keratoacanthomas continue growing, even spreading to other regions of the body.
Melanoma cancers develop from your pigment-making skin cells called melanocytes. Moles are non-cancerous growths from melanocytes, too. But melanomas grow and spread if not treated.