That spot, bump or lump you notice on your arm, leg, face or other part of your body may be more serious than a superficial “age spot” or mole. It could be a sign of melanoma. Any type of new skin growth or discoloration should be checked by a board-certified dermatologist as soon as it is noticed.
There are four basic types of melanoma, and they can affect both the young and the elderly. Three types of melanoma begin on the top layer of skin and can sometimes become invasive, meaning that they will penetrate further into the skin and body. The fourth and most serious type of melanoma is invasive from the start.
Here is a brief overview of the four basic types of melanoma and what to look for:
Superficial spreading melanoma. By far the most common type of melanoma, superficial spreading melanoma accounts for about 70 percent of all cases, and is the type most often seen in young people. This type of melanoma, as its name suggests, grows along the top layer of the skin for a fairly long time before penetrating more deeply. It is most often characterized by these features:
- The onset of a flat or slightly raised discolored patch.
- May have irregular borders and be somewhat asymmetrical in form.
- Color varies, and you may notice areas of tan, brown, black, red, blue or white.
- Can occur in a previously benign mole.
- Can be found almost anywhere on the body.
- Most likely to be found on the trunk in men, the legs in women and the upper back in both.
Lentigo maligna. Similar in nature to the superficial spreading type, lentigo maligna can remain close to the skin surface for a good length of time. It is also the most common form of melanoma in Hawaii. When this type of melanoma becomes invasive, it is referred to as lentigo maligna melanoma. It is most often characterized by:
- The onset of a flat or mildly elevated spot.
- Usually a mottled tan, brown or dark brown discoloration.
- Most common among the elderly.
- Arises on chronically sun-exposed, damaged skin.
- Most commonly found on the face, ears, arms and upper trunk.
Acral lentiginous melanoma. This type of melanoma first spreads along the skin before penetrating more deeply. It differs greatly from the first two in these characteristics:
- Usually appears as a black or brown discoloration under the nails, on the soles of the feet or palms of the hands.
- Often advances more quickly than superficial spreading melanoma and lentigo maligna.
- It is sometimes found on dark-skinned people.
- Most common melanoma in African-Americans and Asians.
- Least common among Caucasians.
Nodular melanoma. This type of melanoma is malignant, and is most often invasive at the time of diagnosis. This is the most aggressive type melanoma, and is found in 10 to 15 percent of cases. It is most often characterized by:
- A recognizable bump.
- Black in color, but skin tone can occasionally appear blue, gray, white, brown, tan or red.
- The most frequent locations are the trunk, legs and arms as well as the scalp in men.
- Occurs mainly in the elderly.
