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Acral lentiginous melanoma
See also in: Nail and Distal Digit
Other Resources UpToDate PubMed

Acral lentiginous melanoma

See also in: Nail and Distal Digit
Contributors: Vivian Wong MD, PhD, William M. Lin MD, Sarah Hocker DO, Susan Burgin MD
Other Resources UpToDate PubMed


Acral lentiginous melanoma (ALM) is a subtype of melanoma that occurs on acral surfaces. It presents as an atypical pigmented lesion on the distal extremities, including the palms, soles, and subungual areas. As in other locations, ALM may be amelanotic in these areas, in which case, a reddish, pinkish, or skin-colored macule, plaque, or nodule is seen. Ulceration may occur and be the predominant finding in long-standing or rapidly growing tumors. The most common location for ALM is on a lower extremity (about 78.3%), and it occurs frequently on the hallux and thumb. The incidence of ALM in men and women is similar, and it most commonly occurs in those aged 50-60 years. ALM accounts for less than 5% of all melanomas.

ALM occurs in all races and ethnicities with a similar incidence; however, it is disproportionately represented compared with other melanoma subtypes among individuals with darker skin colors, including those of African, Hispanic, and Asian descent. In these individuals, the diagnosis is often delayed, and therefore the prognosis is worse than in individuals with lighter skin colors.

Because ALM typically occurs in minimally sun-exposed areas in patients of all phototypes, it has been suggested that sun exposure is less of a risk factor than in the other subtypes of melanoma, indicating other possible etiologies. This has led to the theory that trauma may be a risk factor leading to the development of ALM, and some studies have shown an association with injuries to the foot. Also, ALM occurs more frequently at physically stressed and weight-bearing sites of the volar region and nail apparatus. A pattern of spread has been observed with the long axis along natural creases on the sole. Genomic studies have also revealed different mutational profiles compared with other melanoma subtypes and identified KIT mutations in a subset of acral melanomas.


C43.9 – Malignant melanoma of skin, unspecified

254732008 – Acral lentiginous malignant melanoma of skin

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Last Reviewed:11/07/2021
Last Updated:12/01/2021
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Patient Information for Acral lentiginous melanoma
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Contributors: Medical staff writer


Acral lentiginous melanoma (ALM) is a type of melanoma skin cancer that occurs on the hands and feet. Acral refers to your limbs or extremities and lentigines are dark-colored (pigmented) spots.

In ALM, pigmented cells may form a tumor that looks like a brown or black spot or patch. Sometimes, but not usually, ALM is amelanotic, which means the growing cells are skin-colored or pink.

Who’s At Risk

Both men and women of all races and ethnicities are at risk for melanoma. ALM is the most common type of melanoma in people with dark skin and in people of East Asian descent.

ALM is more common in adults over 50 years of age. People with a family history of melanoma have a higher risk.

Sites where the foot has been previously injured are more likely to develop ALM.

Signs & Symptoms

This form of melanoma often resembles a black, brown, or blue patch or bump. It can be mistaken for a wart. It is usually seen on the foot, but it may be on your hand instead. The tumor can be flat or raised, and it usually has color variation and crooked borders.

Because ALM is sometimes amelanotic, it is possible for the patch or bump to be pink or skin-colored. Ask your health care provider about any unusual growths on your hands or feet, especially if you have a personal or family history of skin cancer.

Self-Care Guidelines

ALM must be treated by a health care professional. It is easier to treat when it is found early. Do a regular self-examination of your skin. Watch darker or lighter patches and moles for changes.

When to Seek Medical Care

Show your doctor all growths or patches under your fingernails and toenails and on your palms and soles.

If you have a parent, sibling, or child with skin cancer, or if you have a personal history of skin cancer, talk to your doctor about being screened for melanoma regularly.


The most common treatment is to remove the melanoma.

More advanced ALM can be treated with chemotherapy or immunotherapy medications.
Copyright © 2023 VisualDx®. All rights reserved.
Acral lentiginous melanoma
See also in: Nail and Distal Digit
A medical illustration showing key findings of Acral lentiginous melanoma : Diffuse black nails, Hyperpigmented patch, Longitudinal pigmented nail bands, Thumb, Toes, Sole of foot, Hyperpigmented macules, Palms
Clinical image of Acral lentiginous melanoma - imageId=1847552. Click to open in gallery.  caption: 'A variegated brown and black, asymmetric plaque on the distal toe with pigment in the toenail.'
A variegated brown and black, asymmetric plaque on the distal toe with pigment in the toenail.
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