Acral melanoma (ALM) is a rare form of skin cancer that develops on the palms, soles, or under the nails. ALM is unique because it is an aggressive melanoma that is not caused by sunlight and ultraviolet (UV) rays that damage the skin.
ALM typically appears as rapidly spreading dark patches with varying degrees of color and irregular borders. This article will explain common symptoms and complications, and you’ll know when to see your healthcare provider for an evaluation.
The earliest sign of acral melanoma is an oddly shaped, discolored patch of skin surrounded by normal skin. The skin may be raised; black, gray, tan, red, or brown; and have irregular borders. Occasionally, brown or tan streaks may appear under the nails of the hands or feet, especially the big toe or thumb.
As with other flat forms of melanoma, the “ABCDE” rule is used to help describe these ominous looking moles, including:
- “A” for asymmetric
- “B” for irregular borders
- “C” for color change
- “D” stands for diameter, large
- “E” stands for its evolving or growing nature
ALM is very rare. However, if you see one or more of the following skin changes, consult a healthcare professional or dermatologist:
- Ulceration or bleeding when you see new oddly shaped or discolored patches of skin
- Enlarged patches of discolored skin
- Irregular skin areas larger than 6 mm
- skin patches that change shape
- Raised skin surface
- Color-changing skin patches
- Skin patches with irregular borders
Other warning signs include:
- New streaks on the nails are birthmarks or due to accidents or bruises
- nail stripes damaged nails
- Moles that change color or shape on the hands or feet
- Raised, thickened plaques on the soles or palms of your feet
Prevalence of ALM
ALM is the least common subtype of all melanomas. However, ALM accounts for 70% of melanomas in blacks, 46% in Asians, and less than 10% in whites.
Can itchy skin be a symptom of cancer?
In rare cases, ALM may appear red or orange – a condition called no pigment (Non-pigmented) melanoma.
Initially, cancer cells in ALM remain on the surface of the skin (a layer called the epidermis), but become invasive and spread as the disease progresses. Skin pits and growths resembling plantar warts (small growths that often appear on the soles of the feet) or fungal infections may indicate that the tumor is actively spreading.
ALM usually occurs under the nail bed, a condition called subungual melanoma. It may appear as distinct discoloration or irregularly colored longitudinal bands or lines (running longitudinally, not transversely) on the nail plate (the hard part of the nail). Advanced melanoma can completely destroy the nail plate.
ALM, a subtype of cutaneous melanoma, is an aggressive cancer that can spread rapidly throughout the body. It can be life-threatening if left untreated.
Getting an accurate diagnosis early is critical to initiating appropriate treatment. It also gives your medical team (which may consist of oncologists (cancer specialists), dermatologists (skin, hair and nail specialists), nurses and support staff) a better understanding of your outlook.
Skin Cancer Prevention – Early Detection
When to see a healthcare professional
ALM is incredibly aggressive, so prompt diagnosis and treatment are key to limiting its spread and the development of medical complications.
See your doctor right away if you notice a pre-existing mole getting larger, skin changes such as raised patches, darkening of the skin surrounded by normal skin, or skin bleeding or ulcers not caused by an injury.
Using the ABDCE technique can also help you spot ominous skin changes. Sudden and unexplained weight loss and more frequent infections can also be signs of serious illnesses such as cancer. If you have a history of cancer or don’t feel like normal, see your primary care doctor or other trusted healthcare professional for a checkup.
Acral melanoma is a rare, aggressive form of melanoma that develops on the palms or soles of the feet and does not cause damage from overexposure to sunlight. Common signs of ALM are abnormally shaped, raised and discolored patches of skin, dark patches surrounded by normal skin, and bleeding within an existing mole that may slowly enlarge over time.
If your mole becomes larger or discolored, you may need to have it checked by a dermatologist. Although ALM is a serious form of melanoma, it is important to note that it is very rare. Even if symptoms are present, your changes may be explained by something other than ALM.
That said, it’s still important to consult a healthcare professional if you notice any skin changes on your body.