Basically, skin cancers fall into two major categories: melanoma and nonmelanoma. Melanoma affects about one in 10 patients with skin cancer. The cancer can begin in heavily pigmented tissue, such as a mole or birthmark, as well as in normal pigmented skin. Melanoma usually appears first on the torso of the body.
The two most common skin cancers, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), are nonmelanomas, progress slowly and seldom spread beyond the skin. They can be detected easily and treated and are rarely life-threatening.
Basal cell carcinoma accounts for about 75 percent of skin cancers. It is the slowest growing and often appears as a pearly or flesh-colored oval lump with a rolled border. In time it may develop into a bleeding ulcer. It may also appear as a smooth red spot indented in the center or a reddish brown or bluish black patch of skin on the chest or back.
Squamous cell carcinoma, on the other hand, tends to be somewhat more aggressive and more inclined to spread. It may appear as a firm, reddish wartlike bump that grows gradually or a flat spot that becomes a bleeding sore that will not heal.
More than 800,000 cases of nonmelanoma are diagnosed each year in the U.S., along with about 35,000 cases of melanoma. Of the 10,000 deaths each year from skin cancer, about 8,000 are from melanoma.