Acral lentiginous melanoma | |
---|---|
Specialty | Oncology, dermatology |
Symptoms | Areas of dark pigmentation [1] |
Causes | Malignant melanocytes[2][3] |
Diagnostic method | Biopsy[4] |
Treatment | Biologic immunotherapy agents[5] |
Frequency | Males = Females[6] |
Acral lentiginous melanoma (ALM) is a type of skin cancer.[6] It typically begins as a uniform brownish mark before becoming darker and wider with a blurred, irregular border. ALM is most frequently seen on the foot of a person with darker skin but can also be found in non-sun exposed areas such as the palms, soles, and under finger and toenails.[6] It may become bumpy and ulcerate.[6] When under the nail it typically appears as dark longitudinal streaks.[7] As it grows, ALM may also spread to other areas of the body.[7]
Melanoma is a group of serious skin cancers that arise from pigment cells (melanocytes); acral lentiginous melanoma is a kind of lentiginous[8] skin melanoma.[6] ALM makes up less than 5% of all melanomas, but is considered the most common subtype in people with darker skin and is rare in people with lighter skin types.[9] It is not caused by exposure to sunlight or UV radiation, and wearing sunscreen does not protect against it. It occurs on non-hair-bearing surfaces of the body, which have not necessarily been exposed to sunlight. It is also found on mucous membranes.[10]
The absolute incidence of ALM is the same for people of all skin colors, and has not changed significantly for decades.[10] However, because rates of other melanomas are low in non-white populations, ALM is the most common form of melanoma diagnosed amongst Asian and sub-Saharan African ethnic groups.[11] The average age at diagnosis is between sixty and seventy years.[12] Males and females are affected equally, but females tend to be diagnosed at earlier stages.[6][7]
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