Actinic keratosis, a warty irregularity on the skin surface that may turn into squamous cell carcinoma, is often treated by destroying it with liquid nitrogen or by applying fluorouracil cream that kills the rapidly dividing skin cells. Melanoma can begin as a new, small, pigmented skin growth on normal skin, most often on sun-exposed areas, but nearly half of the cases develop from existing pigmented moles. The less a melanoma has grown into the skin, the greater the chance of curing it. If a melanoma has grown deep into the skin, it's more likely to spread through the lymph and blood vessels and can cause death within months or a few years. The course of the disease varies greatly and appears to depend on the strength of the body's immune defenses.
Some people survive in apparent good health for many years despite the spread of the melanoma.
Small growths are removed entirely, but only a small piece is removed from larger growths. In either case, a pathologist examines the tissue microscopically to determine if the growth is a melanoma. However, anyone who has had a melanoma is at risk of developing others. Therefore, such people need regular skin examinations. Although chemotherapy is used to treat melanomas that have spread, cure rates are low, and the condition is often fatal.