What is Acral Lentiginous Melanoma: Causes, Prognoses, Treatment, Pictures

Cancer is a collective term for many diseases. All cancers have one thing in common; the fact that they cause healthy body cells to divide abnormally. To identify a specific type, cancers are named according to the body part they invade.

The skin has cells that contain melanin. This is the substance that gives color to the skin. The cells are known as melanocytes. If cancer originates in these cells, it is known as melanoma. It is of all skin cancers the most aggressive. When melanoma develops on feet or hands, it is referred to as acral lentiginous melanoma.

The main difference in this type of melanoma is the fact that its likelihood to develop doesn’t depend on skin color. It for this reason is the most common melanoma in individuals with dark skins. Acral lentiginous melanoma accounts for about 2.5% of all melanomas.

What is acral lentiginous melanoma?

So what is acral lentiginous melanoma (ALM) exactly? To understand what this type of cancer is, it is important that we briefly look at what is melanoma cancer.

Melanoma cancer is a disease that involves abnormal growth of skin cells known as melanocytes. These cells are located in the epidermis. The epidermis is the upper layer of the skin. The fact that melanoma originates in top skin layer makes it easier to treat in early stages with excisional surgery. But like all cancers, melanoma cells usually migrate through circulatory system and lymphatic system. It is for this reason that the disease is as deadly as any other cancer that has metastasized.

The most unique thing about this type of melanoma is the fact that it develops on soles and palms. It can also begin under toenail, in which case it is referred to as subungual melanoma. More cases are reported on feet compared to on hands.

Acral lentiginous melanoma is characterized by a spot on skin. The spot enlarges slowly into a discolored patch. This happens very slowly. In fact, the spot can linger for years before becoming large enough to cause suspicion.

Often, ALM begins as a flat spot on normal skin. It can however originate in preexisting moles. It is almost harmless in its initial stages. Problems set in once cells have divided enough to form a tumor thicker than 1 mm. When this happens, the tumor penetrates deeper into the dermis. It from there is ready to metastasize or migrate and invade other parts of the body.

Acral lentiginous melanoma symptoms

It is tempting to assume that a spot or patch on your sole or hand is a normal blemish such as caused by blood blisters. ALM spots are often dark but can also be orange or reddish (amelanotic). This can be seen in most pictures of melanoma.  When originating in toenails or fingernails, it forms dark streaks beneath the nail.

The ABCDE rule may help you identify suspicious malignant melanomas. It is not an official diagnostic tool, so should not be used to confirm diagnosis. A stands for asymmetry. Malignant moles tend to have irregular halves. For example, it can be large on the left side than it is on the right side. B stands for border. Normal moles have defined borders. C is for color. ALM spots often are multiple colored. Black, brown and blue are usually present. D is for diameter. If a spot is at first less than 1 mm, then grows to about 3 mm after a time, get it checked immediately. ALM patches can enlarge to more than 6 mm. E stands for evolving. Normal moles are not supposed to keep changing size, color or shape. Note that an ALM spot may be smooth at first but later thicken and get flaky or rough.

ALM that originates in nails causes discoloration which spreads to other parts of the nail with time. If not addressed, affected nail will crack. See acral lentiginous melanoma pictures and images for illustration.

Local lymph nodes are often the first organs to be invaded by metastasized melanoma. Malignancy then spreads to distant organs and tissues. It is for this reason that ALM can cause melanoma in brain, lungs, bones or even melanoma on penis. Following symptoms may occur after metastasis:

  • Brain – seizures, headaches and numbness in extremities.
  • Lungs – cough that doesn’t go away. It may also be accompanied by blood. Large tumors will also cause trouble breathing and chest pain.
  • Liver or pancreas – nausea and vomiting are the common symptoms. If the tumor is large, it may be felt as a lump in upper abdomen quadrant. Patients are also likely to lose weight without trying to.
  • Bones – loss of bone density. This results in frequent fractures. Tumors also cause bone pain.
  • Skin – appearance of multiple lesions or patches that resemble initial ones. They can develop further away from where initial tumors originated. It is always advised that you inform your doctor if you are to notice more than one new mole.

Acral lentiginous melanoma causes

Exact acral lentiginous melanoma causes are yet to be discovered. There reasons however to believe that the disease is not associated with UV radiation exposure. This is why dark skinned individuals are as likely to develop the disease as fair skinned ones.

Some reports have suggested that injuries are a predisposing factor, especially for melanoma fingernail symptoms. However, most injuries do not result in ALM. Positive diagnosis in fact rarely has something to do with a past injury.

The fact to be agreed on is that ALM is caused by gene mutation. This is also true with other types of cancer. It may be of some help to compare other forms of melanoma and their causes. To this end, consider topics such as what does vulva melanoma look like and uveal melanoma symptoms.

Acral lentiginous melanoma prognosis and stages

Acral lentiginous melanoma prognosis largely depends on the stage the disease is in. stage 0 melanomas are the easiest to treat. They are very small and are still in the epidermis. 5-year survival rate is almost 100%.

Stage I melanomas are still thin, less than 2 mm in thickness. Their roots have not reached the dermis layer. Survival rate drops to about 95%

At stage II, tumors have reached 2 mm in thickness. New malignant cells are being formed in the dermis. During this stage, melanomas have a tendency to bleed. This makes them very dangerous as malignant cells can easily enter blood system and be transported to other body parts. Survival rate reduces to about 50% to 80%.

When melanomas reach stage III, they migrate into lymphatic system and invade lymph nodes, local ones at first. Survival rate is below 50%.

Stage IV is the final and deadliest. Here, malignant cells have migrated and invaded other organs such as lungs and brain. It is almost not possible to identify or predict where the next tumor will appear. This makes it very hard to treat the disease at this stage. Survival rate is below 20%.

How fast does melanoma spread? Different forms of melanoma spread differently. For example, nodular melanoma can reach its deadliest stage in a matter of months. Acral lentiginous melanoma on the other hand can stay in its initial stage for years without spreading. However, once melanomas have penetrated into the dermis, they usually spread very rapidly. The most important thing to remember is that even a single day of delayed medical attention can have a huge impact on survival rate.

Acral lentiginous melanoma diagnosis

It is very important to seek medical attention regardless of the stage in which the tumor has been caught. Cancer can be very distressing to deal with especially without treatment. Top centers such as Ocular Melanoma Foundation offer top treatment services as well as advice on how to live with the disease. If your doctor suspects presence of ALM cells, they will perform the following tests;


To differentiate between acral lentiginous melanoma and other forms of tumors such as moles and warts, doctors use a dermatoscope. The device is also commonly used for diagnosing other forms of melanoma.


Excision biopsy is a very effective diagnostic tool, not only for acral lentiginous melanoma but also other melanomas. Doctors usually take biopsies from multiple regions of the lesion to ensure that signs of malignancy are not missed.

After positive diagnosis and removal of the tumor, sentinel node biopsy is recommended. This is especially if the tumor had reached thickness of 1 mm. The biopsy checks if malignant cells have migrated into lymph nodes.

Acral lentiginous melanoma treatment

Surgical removal

Most cancers are fully or partly removed surgically and acral lentiginous melanoma is no exception. Melanoma in situ treatment surgery requires excision margins of about 5 mm. melanomas which have reached 4 mm require excision margins of up to 2 cm.

Further surgical operations may be conducted if the doctor suspects incomplete excision. Other forms of surgery include amputation and removal of swollen lymph nodes.


Radiotherapy is commonly used after surgical removal of tumors. It ensures that malignant tissues which survived removal with surgery have been destroyed. The treatment uses X-rays.


During chemotherapy, patients are injected or given drugs that kill fast dividing cells. All cancer cells divide very rapidly and in fact uncontrollably. Chemo has been known to have side effects such as loss of hair. This is because drugs used destroy even healthy cells. To address this issue, a newer form of chemo referred to as targeted therapy has been introduced.


Immunotherapy is often considered when malignancy has spread to other organs. It works by boosting the immune system. Naturally, abnormal cells will be attacked and destroyed by the immune system. The idea behind immunotherapy is to make immune cells more alert and efficient in destroying cancer cells.

Always seek medical attention from a qualified doctor or a certified hospital. Cancer is one of those diseases that require not only technical treatment but also moral support and range of treatment options. This is commonly seen in choroidal melanoma treatment.

How to prevent acral lentiginous melanoma

The most effective way to prevent acral lentiginous melanoma is to be on the lookout for its warning signs. ALM is not fatal. This is unless it has metastasized.

Have your doctor check any spot, patch or lesion on hands, feet or under nails that persist for long and have nothing to do with injury. When diagnosed early, simple excision surgery will be enough to get rid of the tumor.

Another prevention strategy involves follow-up appointments and self-examinations. Learn more on the symptoms of melanoma. The knowledge may greatly help in identifying the disease in its early stages. This has everything to do with the fact that cancer becomes more deadly as it advances.