Squamous cell carcinoma
These cancers are the second most common type of skin cancer, accounting for approximately 20 percent of non-melanoma skin cancers. They develop from the flat, squamous cells that are the primary cell type making up the outermost layer of the skin, the epidermis.
This type of skin cancer is usually found on areas of the skin that have been exposed to the sun, such as the neck or ears, face, or on the back of the hand, but they can develop in other areas, such as in scars or skin ulcers, or in the genital region. Squamous cell cancers usually grow slowly, and it is uncommon for them to spread, or metastasize, but they are more likely than basal cell carcinomas to invade fatty tissue beneath the skin or to spread even further.