Where is Melanoma Found on the Body? Who Gets Melanoma?

The Melanoma Book
by Howard L. Kaufman, M.D., FACS

(Page 5 of 5)

Where is Melanoma Found on the Body?

Melanoma can occur anywhere that melanocytes, the pigment-producing cells of the body, are found. The most common location is the skin, and melanomas arising in the skin are referred to as cutaneous melanomas. As I mentioned, they may occur within an existing mole or may start in a previously normal-appearing part of the skin.

Table 1-4. Distribution of cutaneous melanoma

Skin site	Frequency
Head and neck	22-43%
Chest, abdomen, and back	13-32%
Arms	17-23%
Legs	21-25%
Unknown	2%

Melanomas may also occur in the mucous membranes around the mouth and nasal cavities (called mucosal melanomas) or around the anus (called anal melanomas). Another form of melanoma, called ocular melanoma, can even develop in the eye and is, in fact, the most common tumor of the eye. (Because they do not behave exactly like cutaneous or skin melanomas, mucosal, anal, and ocular melanomas are discussed separately in Chapter 9.)

After a melanoma has spread to other internal organs or lymph nodes, the original site cannot always be identified. Experts believe that, in such cases, the immune system may have destroyed the original (or primary) melanoma.

Table 1-5. Sites of melanoma on the body

Body site	Frequency of melanoma
Skin	92%
Eye	5%
Mucous membranes	2%
Unknown	1%

Who Gets Melanoma?

Melanoma is not a disease of the elderly. Most patients are diagnosed during their forties or fifties. Very rarely, melanoma has been reported in young infants (see the age distribution of melanoma in Figure 1-1). Race is an important filter, as melanoma most commonly strikes Caucasians of European descent. The disease is less prevalent among African Americans and is very rare in the Japanese population. Nonetheless, melanoma can and does occur in nearly all races and can be found all over the world. Melanoma is strongly associated with exposure to the sun, especially for Caucasians. Proximity to the equator also increases your risk of melanoma. The highest risk of melanoma in the world occurs in Australia, where the disease affects 1 in every 60 Australians. Although nothing has been proven yet, this striking increase in melanoma may be related to the degradation of the protective ozone layer (which shields out harmful ultraviolet light), combined with the popularity of sunbathing and outdoor activities.A familial or genetic form of melanoma is responsible for approximately 10 percent of all melanoma cases. The next chapter explains the causes and additional risk factors for developing melanoma.

Why Is Melanoma So Dangerous?

When a melanoma is confined to the skin, it is usually treated easily by surgical removal. If melanoma grows to a certain depth within the dermis, however, some cells may break off and spread. These renegade cells usually enter the lymphatic system in the dermis and spread to nearby lymph nodes. From there they may spread almost anywhere else in the body, where they can cause serious damage to other organs and threaten life.

Although malignant melanoma accounts for only about 5 percent of all skin cancers, it is responsible for about 80 percent of all deaths related to skin cancer. In the United States, an estimated 52,000 people develop melanoma annually; almost 8,000 people die of melanoma each year, or twenty people every day. Melanoma is the sixth leading cause of cancer-related deaths in men and the seventh leading cause of cancer-related deaths in women. Melanoma has become the leading cause of cancer deaths in women between the ages of twenty-five and thirty.

Melanoma is also increasing at a faster rate than almost any other cancer. In 1935 melanoma afflicted 1 of every 1,500 persons living in the United States. This rate has steadily increased by 5-7 percent per year, so that by the year 2000 melanoma struck one in every seventy-five persons. The true incidence of melanoma may be much higher, since many skin lesions are destroyed by freezing, laser ablation, and other methods where biopsy confirmation of melanoma is not obtained or reported.

Although this data may sound disturbing, there is some good news: Despite the soaring number of melanoma cases, the mortality rate has not increased proportionately during the last twenty years. This may be due to the fact that melanoma is being detected earlier, when it is more likely to be cured, or it may be that better surgical techniques are achieving better cure rates.

In the next few chapters you will learn more about the causes of melanoma and how to prevent the disease, how to identify melanoma, and current treatment options and experimental therapies being developed for patients with melanoma.

Columbia Melanoma Center Case Studies

A thirty-two-year-old medical resident named Juan was working at the hospital when he noticed a dark, pigmented skin lesion on his left great toe, which had increased in size for about three months. Originally from Puerto Rico, he had spent a lot of time in the sun but there was no melanoma in his family. When I examined Juan, I found a one-centimeter smooth, flat blue-black pigmented lesion over the upper part of his toe. There was no evidence of abnormal lymph nodes in the leg or groin. We performed an excision of the skin lesion using a local anesthetic. After the pathologist reported that the lesion was a blue nevus and the margins of the lesion were all normal skin, I was able to reassure Juan that this was not melanoma. I advised him to have his dermatologist do at least an annual checkup, sooner if he notices any other unusual skin lesions.

This case is typical of pigmented skin lesions. The change in the size of the lesion over a three-month period was the most worrisome sign and the reason Juan was referred for evaluation. Like most people's pigmented skin lesions, his turned out to be of no serious consequence. The pathology report confirmed that the lesion was benign and the excision provided adequate treatment for Juan. Although I might have chosen to simply observe the skin lesion and remove it later, the recent change in size and Juan's peace of mind made me opt for excision.

Ask Your Doctor

IF YOU DEVELOP A NEW SKIN LESION OR NOTICE A CHANGE IN AN OLD SKIN MOLE, ASK THE FOLLOWING QUESTIONS:

1. Is the lesion pigmented or non-pigmented? Pigmented lesions are usually brown or black and are more worrisome for melanoma than non-pigmented lesions.

2. Is the lesion suspicious for malignancy or cancer? Many doctors will have experience looking at skin lesions and may be able to tell you what the problem is by simple inspection.

3. Should I see a dermatologist? A dermatologist is a doctor who has additional training in diseases of the skin and may be better equipped to identify difficult lesions. Many dermatologists are also trained in the treatment of skin cancers.

4. Do I need a biopsy? A biopsy is the only way to be certain of what the lesion is. It must be examined by a trained pathologist with experience in skin diseases. Always ask that your doctor review the pathology report with you after any biopsy procedure.

5. Is my family at risk for developing a skin lesion or cancer? Some types of skin cancer, especially melanoma, may be more common in close relatives. If your doctor believes that you have this type of cancer, it may be helpful to have close family members (parents, children, and siblings) see a dermatologist for a routine examination or screening so that lesions can be detected as early as possible.

Copyright © 2005 Howard L. Kaufman, M.D., FACS

About the Author

Dr. Howard L. Kaufman is founder and Co-Director of the Columbia University Melanoma Center, attending physician at The New York Presbyterian-Columbia University Medical Center, chief of surgical oncology, and associate professor of surgery at Columbia University College of Physicians and Surgeons. He has conducted numerous clinical research trials on vaccines for cancer, lectures widely on cancer treatment and has published more than 100 articles in the field of tumor immunology and immunotherapy. He lives in New York City.