Types of Non-Melanoma Skin Cancer
Basal Cell Carcinoma
Basal cell carcinoma (BCC) is the most common form of skin cancer. It affects over half a million Americans each year and represents about one-third of all newly diagnosed cancers in the United States. The growth of BCC begins in the basal cells, which are found in the bottom regions of the epidermisthe outermost layer of the skin. Sometimes it is mistaken for noncancerous skin conditions like eczema or psoriasis, since it may appear as a red, itchy, patch or sore. It also may take the form of a raised, pearly or waxy lesion. Small blood vessels may grow around the surface of the lesion and may bleed after minor injury.
Five recognized warning signs of BCC are a:
- red patch or irritation that may crust, itch, or hurt;
- pearly or translucent bump, or a bump that is tan, brown or black;
- non-healing sore that bleeds, oozes or crusts;
- pink growth with a slightly raised, rolled border and a central scab-like indentation (with/without the growth of tiny blood vessels; or a
- shiny, taut, scar-like patch that may be waxy, white, or yellow in color and has indistinguishable borders.
BCC usually affects sun-exposed areas of the skinthe nose being the most familiar site. It can be locally destructive, and it is likely to recur in areas such as the center of the face (areas around the eyes, the eyelids, the skin above the lip, and the nose-cheek angle), forehead, scalp, and skin behind the ears, earlobe and ear canal. The fifth, scar-like form of BCC, which is also known as morphea-form BCC, is an especially aggressive form of BCC. Because the margins of this tumor may be indistinct, morphea-form BCC often is difficult to manage with traditional therapies.
Squamous Cell Carcinoma
Squamous cell carcinoma (SCC) develops in about 80,000 to 100,000 Americans each year. It may appear as a raised, rough, expanding lump or as a slowly expanding red spot. SCCs, like basal cell carcinomas, tend to occur on sun-exposed areas of the skin, such as the ears, lower lip, and tops of the hands. When SCC is in its earliest form and is confined to the epidermis, it is known as squamous cell carcinoma in situ, or Bowen's disease. At this stage, the cancer cells have not yet grown beyond the top skin layer into the dermis, and the lesion often looks like a reddish patch. If Bowen's disease occurs on the skin near the reproductive organs or anus, it may be associated with the sexually transmitted disease known as human papillomavirus (HPV)the virus responsible for genital warts.
The skin condition known as actinic keratosis also is a potential forerunner of SCC. Actinic keratosis (also known as solar or senile keratosis) is caused by chronic sun exposure, and it produces red, scaly patches which, in about 5% of all cases, eventually may become squamous cell carcinomas. Other skin abnormalitiessuch as burn scars, chronic inflammation, long-standing skin ulcers, arsenic exposure, or prior radiation therapymay increase a person's risk of developing SCC. The prognosis (outcome) of SCC has been found to be worse if tumors occur in non-sun-exposed skin or if they repeatedly occur in sun-exposed skin. This is because such tumors are prone to metastasis (spread).