
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. Over 51,000 new cases are reported
to the American Cancer Society each year, and it is probable that
a great many more occur and are not reported.
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 tumor 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. This is the most
aggressive of the melanomas, and is found in 10 to 15 percent of
cases.
Malignant Melanomas:
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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