The most common types of skin cancer are basal cell carcinoma and squamous cell carcinoma. Both types enlarge locally from their point of origin and usually do not spread (metastasize) to distant parts of the body. If not completely removed, both types will frequently invade and destroy structures in their paths of growth. Compared to other forms of cancer, these types of skin cancer are generally recognized in their early stages and are therefore more easily cured.

The cause of skin cancer, like other forms of cancer, is not completely known. Excessive exposure to sunlight is the single most important factor associated with the development of these skin cancers, which appear most commonly on the face and the arms (the most sun-exposed parts of the body). Fair-skinned people develop skin cancer more frequently than dark-skinned people. Skin cancer, unlike cancer of the other organs, is rarely found in African Americans.

Skin cancer also tends to be hereditary and occurs very frequently in certain ethnic groups, especially those with fair complexions such as Northern Italians and Celtics (especially Irish). Other possible factors contributing to the development of skin cancer include x-rays, trauma and certain chemicals.

Skin cancer begins in the uppermost layer of the skin and grows downward, forming roots, spreading horizontally along the surface of the skin. Unfortunately, these extensions cannot be directly visualized. Therefore, what is apparent to the naked eye on the surface of the skin actually may be only the “tip of the iceberg”.