Dr Paul O'Brien
About Melanoma
Melanoma is the most serious form of skin cancer. Even so, if
diagnosed and removed while it is still thin and limited to the
outermost skin layer, it is almost 100% curable. Once the cancer
advances and metastasizes (spreads) to other parts of the body,
it is hard to treat and can be deadly. During the past 10 years
the number of cases of melanoma has increased more rapidly than
that of any other cancer. The melanoma incidence rates in
Australia and New Zealand are around four times as high as those
found in Canada, the United States and the United Kingdom
Relative five-year survival rates for all melanoma are 90% for
Australian males and 95% for Australian women. Survival rates
have risen significantly since the early eighties as a result of
early detection.
What is melanoma?
The answer to the question asked by patients, their families, and other concerned people is that melanoma is the most serious form of skin cancer. To reach a more complete understanding, it is necessary to learn how the cells in the body become malignant.
The Origin of Melanoma
Melanoma is a malignant tumour that originates in melanocytes, the cells which produce the pigment melanin that colors our skin, hair, and eyes and is heavily concentrated in most moles. The majority of melanomas, therefore, are black or brown. However, melanomas occasionally stop producing pigment. When that happens, the melanomas may no longer be dark, but are skin-colored, pink, red, or purple.
Some Are More Dangerous
The physician will tell you whether the melanoma is early or advanced by describing it as either in situ or invasive. "In situ" is Latin and means "in one site" or "localized." Melanomas in situ occupy only the uppermost part of the epidermis, the top layers of the skin.
Invasive melanomas are the more serious, as they have penetrated more deeply into the skin and may have travelled from the original tumor through the body.
The Four Basic Types
Melanomas fall into four basic categories. Three of them begin in situ and sometimes become invasive; the fourth is invasive from the start. It is helpful to recognize the names and be able to define the characteristics of each type.
- Superficial spreading melanoma is by far the most
common type, accounting for about 70 percent of all cases.
As you might expect, this melanoma travels along the top
layer of the skin for a fairly long time before penetrating
more deeply.
The first sign is the appearance of a flat or slightly raised discolored patch that has irregular borders and is somewhat geometrical in form. The color varies, and you may see areas of tan, brown, black, red, blue, or white. Sometimes an older mole will change in these ways, or a new one will arise. The melanoma can be seen almost anywhere on the body, but is most likely to occur on the trunk in men, the legs in women, and the upper back in both. Most melanomas found in the young are of the superficial spreading type.
- Lentigo maligna is similar to the superficial
spreading type, as it also remains close to the skin surface
for quite a while, and usually appears as a flat or mildly
elevated mottled tan, brown, or dark brown discoloration.
This type of in situ melanoma is found most often in the elderly, arising on chronically sun-exposed, damaged skin on the face, ears, arms, and upper trunk. Lentigo maligna is the most common form of melanoma in Hawaii.
Lentigo maligna melanoma is the invasive form.
- The third type of melanoma, acral lentiginous
melanoma, also spreads superficially before penetrating
more deeply. It is quite different from the others, though,
as it usually appears as a black or brown discoloration
under the nails or on the soles of the feet or palms of the
hands. This type of melanoma is sometimes found in
dark-skinned people.
It is the most common melanoma in African-Americans and Asians, and the least common among Caucasians.
- Unlike the other three types, nodular melanoma, is usually invasive at the time it is first diagnosed. The malignancy is recognized when it becomes a bump. The color is most often black, but occasionally is blue, gray, white, brown, tan, red, or skin tone.
The most frequent locations are the trunk, legs, and arms, mainly of elderly people, as well as the scalp in men.
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Malignant melanomas are usually small brown-black or larger multicolored patches, plaques or nodules with irregular outline. They may crust on the surface or bleed. Many of them may arise in pre-existing moles. |
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