Melanoma of the Nails
Last updated: April 2023
Melanomas usually develop on areas of the body that get the most sun exposure, such as the chest, face, back, legs, ears, and arms. However, did you know that melanoma can also form under the nails? It’s rare, but “subungual melanoma” (melanoma of the nails) accounts for approximately 2% of all melanoma cases.1,2
Quick facts about nail melanoma
- Over 60% occur in the fingernails, and about 40% occur in the toenails.1
- Subungual melanoma begins in the nail matrix (the part of the nail bed that protects the underlying skin).3
- It is most commonly diagnosed in the thumbs and big toes.3
- Unlike many melanomas, subungual melanoma is not caused by sun exposure.3
What does melanoma on the nail look like?
Subungual melanomas usually appear as a brown or black streak under the nail.3,4 Typically, these streaks gradually increase in size and are usually larger than 3mm.1 Unlike nail infection or trauma to the nails, subungual melanoma typically affects one nail at a time.3,4
Other symptoms include:
- Nail separating (‘lifting’) from the nail bed4
- Nail brittleness and cracking3
- A nodule underneath the nail3
- Darkening of the skin next to the nail (known as Hutchinson’s Sign)2
Mistaken for a bruise
Many people first mistake subungual melanoma as a bruise.3,4 However, unlike a bruise, the streaks from subungual melanoma do not heal or grow out with the nail over time.4 It can also be confused with normal pigmentation of the nail bed or a fungal infection.2 While you can have a streak or bruising under the nail that isn’t melanoma, you should ask a dermatologist to check your nails if you notice any changes.
What’s my risk of getting melanoma on my nail?
Subungual melanoma is more common in patients who:
- Have a personal or family history of melanoma2
- Have a personal or family history of atypical moles2
- Are over 50 years of age3
- Are non-Caucasians (approximately 35% of cases), versus Caucasians (2% of cases)3,4
Prevention and early detection
The exact cause of subungual melanoma is unknown, meaning that patients cannot take specific steps to prevent this condition. However, because it may be associated with trauma to the hands and feet, you may want to keep yours hands and feet protected.2 For example, you can protect your hands and feet by wearing gloves during heavy labor, or wearing protective gear and sturdy shoes during sports.
Early detection is crucial to the treatment of subungual melanoma, so be sure to tell your doctor about any changes to your nails.1 You can regularly check your nails, fingers, and toes for any bruising, streaking, or changes.3
Diagnosing melanoma on the nail
To diagnose subungual melanoma, your healthcare provider will likely perform a biopsy. Most often, your provider will numb the affected toe or finger and then use a punch biopsy (a biopsy tool with a tube-shape and sharp end) to remove a piece of the nail for testing.3
To treat subungual melanoma, most healthcare providers will do a minor procedure to excise (cut out) the nail and surrounding nail bed. This procedure is known as a “wide local excision”, and is usually performed with local anesthesia (numbing).2
Prognosis for melanoma on the nail
Like other forms of melanoma, subungual melanoma can metastasize (spread) to other parts of the body if left untreated.3,4 Because it can be difficult to see and is often mistaken for a bruise or other nail problem, this condition often goes undetected. However, checking your nails and showing any changes to your healthcare provider can help reduce your chances of an undetected subungual melanoma.
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