Cancer that forms in the squamous cells of the skin and other tissues around the body is called squamous cell carcinoma. This type of cancer is actually typically not life-threatening, however, in some cases, this type of cancer can be aggressive. When it is not treated, squamous cell carcinoma can grow large enough to begin spreading around the body. Squamous cell carcinoma can develop in any region where squamous cells are present which includes the skin surface, digestive and respiratory linings, and the lining of hollow organs.
One of the most common forms of squamous cell carcinoma is skin cancer. This occurs when there is a mutation in the DNA of skin cells within the top or middle layer of the skin or the epidermis and the dermis. Most often this occurs as a result of built-up skin damage from excessive UVB sunlight or ultraviolet radiation sunlight. This DNA mutation creates abnormal and non-functioning cells that rapidly multiply forming a hard, scaly lump with or without ulceration. The most common places where squamous cell carcinomas of the skin are found include the neck, lips, legs, head, ears, arms, and hands, all of which are not usually covered with clothing. Individuals with fair toned skin, childhood freckling, and excessive cumulative sunburns are at an increased risk of developing squamous cell carcinoma of the skin.