Subungual Melanoma

Medically reviewed by Christina Chun, MPH on August 2, 2017Written by Kristeen Cherney on August 2, 2017

What is subungual melanoma?

Subungual melanoma is a type of melanoma in the nails. Unlike other types of nail melanoma that grow in the surrounding skin, this type begins in the nail matrix. The nail matrix is a part of the nail bed that protects the underlying skin. Sometimes melanoma looks like other conditions that affect the nail bed, such as a bruise.

While subungual melanoma is a relatively rare condition compared to other skin cancers, it can lead to serious complications. Early detection and treatment is a must. It’s important to learn the signs of subungual melanoma so you can get help before the cancer spreads.

What are the symptoms of subungual melanoma?

When you hear the word melanoma, your first thought might be irregular-shaped moles on the skin caused by sun damage. But since subungual melanoma affects the nail matrix, the signs and symptoms don’t look like a typical mole on the skin.

Symptoms of this condition include:

  • a light- to dark-brown colored band on the nail that’s usually vertical
  • a dark band on the nail that slowly expands and covers more of the nail
  • dark nail pigmentation that expands to the surrounding skin
  • a nodule underneath the nail with or without a pigmentation band
  • nail brittleness and cracking
  • bleeding at the site of pigmentation

It’s important to note that not all cases of this condition cause pigmentation changes in the nail. While this can make the melanoma more challenging to detect, a telltale sign of the condition is that it usually affects one nail at a time.

What causes subungual melanoma?

Most cases of skin melanoma are caused by sun exposure. This is why dermatologists warn against tanning and unprotected sun exposure. However, subungual melanoma isn’t usually caused by the sun. Most cases seem to be caused by injury or trauma. It also tends to affect middle-aged and older adults with darker skin.

Additionally, subungual melanoma is more prevalent in the nails of your thumbs and big toes.

How is subungual melanoma diagnosed?

Subungual melanoma is difficult to detect on your own. As a rule of thumb, you should see your doctor right away if you notice any unusual changes or growths in your nail.

To correctly diagnose subungual melanoma, your doctor will need to conduct a biopsy. It will most likely be a punch biopsy, which is a procedure in which a tube-like instrument with a sharp end works like a cookie cutter to take a small sample. This small sample will be tested for melanoma. The biopsy can also be used to rule out other conditions, such as fungal infection.

Can subungual melanoma cause complications?

Subungual melanoma that isn’t treated can metastasize, or spread to other parts of your body. You can learn more about metastatic melanoma here.

Your doctor may recommend amputating the finger or toe the melanoma first developed in to prevent this. However, this method is debatable. According to a literature review, amputation doesn’t seem to improve overall outlook more than traditional surgical treatment for subungual melanoma.

How is subungual melanoma treated?

Subungual melanoma is treated surgically. Your doctor will first remove your entire nail and then remove the growth. To date, surgery is the only viable treatment method for this type of melanoma.

What is the outlook for subungual melanoma?

With early treatment, the outlook is positive. Not only will your doctor remove the nail growth, but they can also help stop melanoma from spreading to other parts of the body.

Early diagnosis is essential to the successful treatment of subungual melanoma. It’s estimated that there is an average 5-year survival rate of 16 to 80 percent. This wide percentile is attributed to the timing of diagnosis and accounts for delayed diagnosis due to a variety of factors, including misdiagnosis.

Can subungual melanoma be prevented?

Since subungual melanoma isn’t caused by sun exposure, it can be difficult to prevent compared to other types of melanoma. General hand and foot health can be of some benefit, though.

Be sure to protect your fingers and toes from injury during sports and other activities by wearing the right type of gear. You should also inspect these areas regularly for any unusual changes.

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