Question:
Please give me some information on melanoma types.
Answer:
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.
1. 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.
2. 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.
3. 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.
4. 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.
