Chapter 3 - Cancers - Basal-cell Cancer,
Squamous-cell Cancer & Keratoacanthoma.....

Three types of skin cancer make up over 99% of all skin cancers. At a future date, we will add a section on rare skin tumors, of which there are thousands, to this Web site, but for the general public, most of what matters is covered by the "big three." They are, in order of commonness, basal-cell carcinoma, squamous-cell carcinoma, and melanoma. In order of their usual lethal potential, they are melanoma, squamous-cell carcinoma and basal-cell carcinoma. These names refer to the types of skin cells from which these cancers are derived. Most cases of skin cancer are either basal-cell or squamous-cell carcinomas. Squamous cells make up most of the epidermis (surface layer of the skin). Basal cells occur in smaller numbers and are located in the lowest part of the epidermis. Of the two, basal-cell carcinoma usually grows more slowly. Basal carcinoma very rarely spreads through the blood or lymph to distant parts of the body, and is considered a cancer mostly because it invades and destroys the tissues around it. Malignant melanoma, on the other hand, may be life threatening if not treated early. Melanoma commonly, but not always, appears as a brownish-black spot or bump in the skin that enlarges and sometimes bleeds. Sometimes melanomas arise in moles that have been present for many years. ......We now refer you to the specific section on whichever tumor you wish to research. You may research precancers and other growths leading to melanoma, basal-cell cancer and squamous-cell cancer in the Web site subsection entitled Precancers.