Melanoma is a type of skin cancer -- one of the most serious types because advanced melanomas have the ability to spread to other parts of the body. (Melanoma can also develop in the eye, called intraocular melanoma, or rarely in other parts of the body where pigment cells are found. The CIS can provide information about the diagnosis and treatment of intraocular melanoma.) Melanoma begins when melanocytes (pigment cells) gradually become more abnormal and divide without control or order. These cells can invade and destroy the normal cells around them. The abnormal cells form a growth of malignant tissue (a cancerous tumor) on the surface of the skin. Melanoma can begin either in an existing mole or as a new growth on the skin. The "Pictures of Melanoma" section shows examples of melanoma. A doctor or nurse specialist can tell whether an abnormal-looking mole should be closely watched or should be removed and checked for melanoma cells. The purpose of routine skin exams is to identify and follow abnormal moles.

The removal of the entire mole or a sample of tissue for examination under a microscope is called a biopsy. If possible, it is best to remove moles by an excisional biopsy, rather than a shave biopsy.

If the biopsy results in a diagnosis of melanoma, the patient and the doctor should work together to make treatment decisions. In many cases, melanoma can be cured by minimal surgery if the tumor is discovered when it is thin (before it has grown downward from the skin surface) and before the cancer cells have begun to spread to other places in the body. However, if melanoma is not found early, the cancer cells can spread through the bloodstream and lymphatic system to form tumors in other parts of the body. Melanoma is much harder to control when it has spread. The spread of cancer is called metastasis.

Doctors and scientists believe that it is possible to prevent many melanomas and to detect most others early, when the disease is more likely to be cured with minimal surgery. In the past several decades, an increasing percentage of melanomas have been diagnosed at very early stages, when they are quite thin and unlikely to have spread. Learning about prevention and early detection, while important for everyone, is especially important for people who have an increased risk for melanoma. People who are at an increased risk include those who have dysplastic nevi or a very large number of ordinary moles.

Risk Factors for Melanoma Family history of melanoma Dysplastic nevi History of melanoma Weakened immune system Many ordinary moles (more than 50) Ultraviolet (UV) radiation Severe, blistering sunburns Freckles Fair skin

The National Cancer Institute booklet What You Need To Know About™ Melanoma has more information about risk factors for this disease.

It is important to remember that not everyone who has dysplastic nevi or other risk factors for melanoma gets the disease. In fact, most do not. Also, about half the people who develop melanoma do not have dysplastic nevi, and they may not have any other known risk factor for the disease. At this time, no one can explain why one person gets melanoma while another does not. Research has shown that sun exposure, especially excessive exposure that leads to bad, blistering sunburns, is an important and avoidable risk factor. Scientists are continuing their studies of risk factors for melanoma.

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