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Four basic types of melanoma Melanomas are divided into 4 main types depending on their location, shape and whether they grow outward or downward into the dermis.
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 Superficial spreading melanoma is by far the most common type accounting for about 70 percent of all cases. As you might expect from the term, this melanoma travels along the top layer of the skin for a long time before penetrating more deeply. The first sign is the appearance of a flat or slightly raised discoloured 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 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. Acral Lentiginous Melanoma The third type of melanoma, acral lentiginous melanoma, also spreads superficially before penetrating more deeply. It is quite different from the others 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. Nodular Melanoma 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, grey, 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. Malignant melanoma symptoms The warning signs of basal and squamous cell carcinoma are:
Signs of melanoma can be detected using the "ABCDE rule" devised by the American Academy of Dermatology. Asymmetry. Most moles are symmetrical. If you drew a line through the middle, the two halves would mirror each other. Melanomas are asymmetric: their two halves are not mirror images. Border. Most moles have a distinct border. The border of a melanoma is likely to be notched, scalloped, or indistinct. Color. Moles may be either dark or light, but they tend to be all the same color. Early melanomas are more likely to be uneven in color or a mixture of several different hues. Diameter. Once a melanoma has acquired its A, B, and C characteristics, it is also likely to be more than 6 millimeters wide (about the size of a pencil eraser). Elevation. A mole that is raised above the skin and has an uneven surface. Changes in the skin are not sure signs of cancer and it is important to see a doctor if any signs last longer than four (4) weeks. |
The physician will tell you whether the melanoma is early or advanced by describing it as either in situ or invasive. "In situ" 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 traveled from the original tumor through the body.|
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. Shown in the photos are typical examples of Superficial Spreading Melanoma. |