Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is the second most common form of skin cancer (BCC > SCC > Melanoma).  An estimated 700,000 cases of SCC are diagnosed each year in the US, resulting in approximately 2,500 deaths.  Like BCC, SCC is mainly caused by cumulative UV exposure; however, it is more dangerous than BCC because it can spread to the lymph nodes or other organs, and in some cases be fatal.

Whereas basal cells are only found in the epidermis, squamous cells are found in both the epidermis and mucosal membranes.  Thus, SCCs can also occur on the genitals and inside the mouth, nostrils, and eyelids.

SCCs often look like scaly red patches, open sores, elevated growths with a central depression, or warts.  They may also crust or bleed.

SCC in situ (also known as Bowen’s disease):  An early form of cancer that has yet to penetrate the basement membrane and is still confined to site of the original cancer cell.  Often appears as a thick scaly red rash.

Well differentiated SCC:  The cancer has penetrated the basement membrane and is now spreading through the dermis and adjacent tissues.  It is now able to metastasize (spread to other organs and form secondary tumors there)  These often appear as very thick, crusty lesions with tops that may fall off but invariably grow back.

Aggressive, poorly differentiated SCC:  The most dangerous type of SCC because it grows very quickly and has a greater tendency to metastasize.  They have a wide variety of appearances (soft, hard, open sores, etc.)


Actinic keratosis:  Common sunspots, the least dangerous type of SCC (more of a pre-cancer).  The surrounding skin often looks sun damaged (blotchy, freckled, and wrinkled).