Squamous cell cancer of the skin is a common cancer, and the number of cases increases every year. Read below to learn more about this common skin cancer.


Some Facts

Squamous cell skin cancer is the second most common skin cancer, behind basal cell carcinoma. Approximately 1 million cases of squamous cell skin cancer are diagnosed in the United States every year. But that’s probably an underestimate! Unlike other cancers, nonmelanoma skin cancers are not tracked by government health officials in a database (registry), so the number of cases is probably higher than the estimate.

Approximately 7,000 people in the United States die from squamous cell skin cancer each year. In the southern and central parts of the United States, squamous cell skin cancer is more common because of increased sun exposure. In these regions, the death rate from squamous cell skin cancer approximates that of kidney cancer, head-and-neck cancer, and melanoma.


The approximate number of people who die from
squamous cell skin cancer in the U.S. each year

Squamous cell skin cancer is a growing problem: The number of new squamous cell skin cancer cases occurring every year (incidence) increased nearly three-fold in the 35-year period ending in 2010.

Why are the numbers rising?

  • We are doing more skin cancer screening, which means we find more types of skin cancers, such as squamous cell skin cancers
  • The population is aging—we know that squamous cell skin cancers are caused by cumulative sun damage to the skin
  • Our ultraviolet (UV) radiation exposure is increasing because of the depletion of the ozone layer

Details About This Cancer

Squamous cell skin cancer arises from squamous cells in our skin. It is one of three more common types of skin cancer as discussed below. As shown in the diagram, the top layer of your skin, the epidermis, is made up of basal cells, melanocytes, and squamous cells. The basal cells form the bottom portion of this layer, and these cells eventually move up, change, and become the squamous cells that flake off. If basal cells become cancerous, the condition is known as basal cell carcinoma (BCC). Melanocytes are the cells that produce a brown pigment called melanin to add color to our skin. If these cells become cancerous, the condition is called melanoma. Squamous cells, which are found in the upper portions of the epidermis, make a protein called keratin, which is found in our skin, hair, and nails. When they grow out of control and become cancerous, they develop into squamous cell skin cancer. Heard of other cancers called squamous cell carcinomas? See the box Science Sidebar.

What is squamous cell skin cancer like? For pictures of squamous cell skin cancer, see Images. Here are some details to know about this cancer:

  • Occurs most commonly on sun-exposed skin, such as the back of the hands, ears, scalp, etc. However, squamous cell skin cancer can also occur in unexpected places like inside the mouth, on the genitals, inside the anus, or beneath a fingernail/toenail
  • Looks like red, scaly patches, or scaly bumps. Sometimes it looks like a wart-like growth
  • Grows over the course of weeks to months
  • Can be tender/painful and can crust over, be itchy, and bleed
  • Varies in size
  • Can cause numbness, pain, and muscle weakness if invading a nearby nerve

Science Sidebar

All These Squamous Cell Cancers!

Did you ever scrape the inside of your cheek and look at the cells under the microscope in science class? Those were squamous cells, as shown in the image.

Because squamous cells line structures both on the inside and outside of the body, people can develop squamous cell carcinomas in many body parts beyond the skin, including the lung, head, neck, and esophagus. Don’t get confused when you are doing your research: Squamous cell lung cancer, squamous cell head-and-neck cancer, squamous cell esophageal cancer, and squamous cell skin cancer are all different cancers. This website will use the term squamous cell skin cancer to be clear that we are talking about squamous cell carcinoma as it occurs in the skin.