Acral melanoma, sometimes called acral lentiginous melanoma, is a rare subtype of melanoma that forms on the palms, soles of feet, or under finger or toe nails. Unlike cutaneous (skin) melanoma, it is not believed to be caused by sun exposure and therefore occurs in areas not typically exposed to the sun. Acral melanoma affects people of all races and ethnicities.
What are the signs and symptoms of acral melanoma?
The symptoms of acral melanoma can vary depending on the location and stage of the cancer. Some common symptoms to look out for are:
- A black, gray, tan, or brown spot; patch; or discoloration on the palms of the hands or soles of the feet.
- Any changing spot that may be growing on the hands or feet.
- A new or changing mole on the hands or feet: This may appear suddenly or gradually, and it may be larger than other moles on your skin.
- Darkened streaks or discolorations that run vertically across the bed of your toenails or fingernails which can ultimately cause breaks and cracks in the nail. This is called subungual melanoma which is a subtype of acral melanoma.
- A spot or patch on the hands or feet that itches, bleeds, or is painful. These may be signs that the cancer is growing or spreading.
If you notice any unusual spots or changes on your skin, including your palms of your hands and soles of your feet or any streaks under your nailbeds, it's important to have them evaluated by a dermatologist or other medical professional. Early detection and treatment of melanoma can be critical for a positive outcome.
How common is acral melanoma?
Acral melanoma is a rare form of melanoma, accounting for only about 1-3% of all cases diagnosed. About 2,000 - 3000 cases of acral melanoma are diagnosed each year in the United States.
How serious is acral melanoma?
The prognosis for acral melanoma depends on several factors, including the size and location of the tumor, the stage of the cancer at diagnosis, and the patient's overall health. Acral melanoma generally has a poorer prognosis than cutaneous melanoma as it often goes undetected until it has reached an advanced stage. Other factors that may contribute to a worse prognosis include differences in genomics between acral and cutaneous melanoma tumors. However, the exact cause of poorer prognosis in acral melanoma patients is currently unknown and an active area of research.
The five-year survival rate for acral melanoma is lower when compared to cutaneous melanoma. Differences in survival between acral and cutaneous melanoma become more pronounced in advanced stages of the disease (Stage 3 and Stage 4 melanoma).
Who gets acral melanoma?
Acral melanoma can occur in anyone, but it is more common among people with darker skin tones, such as African Americans, Asians, and Hispanics. It is also more common in older adults.
What causes acral melanoma?
The potential causes of acral melanoma are not yet fully understood. However, acral melanoma is not believed to be associated with sun exposure. Studies to identify genetic and environmental risk factors contributing to acral melanoma are currently being performed.
How is acral melanoma treated?
Surgery is the primary treatment for acral melanoma, and it may involve removing the tumor and a margin of healthy tissue around it. In some cases, lymph nodes may also be removed to check for the spread of cancer.
Other treatments for acral melanoma may include radiation therapy, immunotherapy, targeted therapy based on a genomic alteration in the tumor, or chemotherapy. These treatments may be used alone or in combination with surgery, depending on the stage and extent of the cancer. Some therapies that have been approved for cutaneous melanoma do not work as well to treat acral melanoma. That is why research is being conducted to find new types of therapies and combinations of therapies that work better in acral melanoma.
It's important to work closely with a team of medical professionals, including a dermatologist, oncologist, and surgeon, to develop a personalized treatment plan that takes into account your individual needs and circumstances. With early detection and appropriate treatment, the prognosis for acral melanoma can be positive.
For patients facing rare melanoma subtypes, including those with acral melanoma, it’s important to see a doctor who specializes in treating patients with your specific type of melanoma. Learn more about choosing your doctor and getting a second opinion for acral melanoma.
Photos of acral melanoma:
Photo Credit: CDC/ Carl Washington, M.D., Emory Univ. School of Medicine; Mona Saraiya, MD, MPH