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% of subungual melanomas 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
Subungual melanoma is most commonly diagnosed in the thumbs and big toes.3
Unlike many melanomas, subungual melanoma is not caused by sun exposure.3
How to spot nail melanoma
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 of nail melanoma 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
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 Subungual melanoma 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 nail melanoma?
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 of nail melanoma
The exact cause of subungual melanoma is unknown, meaning that patients cannot take specific steps to prevent this condition. However, because subungual melanoma may be associated with trauma to the hands and feet2, you may want to keep yours hands and feet protected. 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 nail melanoma
To diagnosis 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
Nail melanoma treatment
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 nail melanoma
Like other forms of melanoma, subungual melanoma can metastasize (spread) to other parts of the body if left untreated.3,4 Because subungual melanoma 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.
Verma, Rajesh, et al. "A Rare Case of Subungual Melanoma." Indian Journal of Dermatology, vol. 60, no. 2, Mar.-Apr. 2015, pp. 188-90, www.ncbi.nlm.nih.gov/pmc/articles/PMC4372915/?report=printable. Accessed 13 Oct. 2017.
Cochran, A. M., et al. "Subungual Melanoma: A review of current treatment." Plastic & Reconstructive Surgery, vol. 134, no. 2, Aug. 2014, pp. 259-73.