Yes, melanoma can grow in the nail unit, and it’s a well-known fact among dermatologists that this type of melanoma has a poor prognosis.
“Nail melanoma, which is in the category of acral lentiginous melanoma encompassing melanomas of the palms, soles and nail apparatus, may have a worse prognosis vs. melanoma elsewhere on the skin — not because they are inherently more aggressive, but because they may not be diagnosed until later in their course,” explains Emily de Golian, MD, a board certified dermatologist with Dermatology Consultants, P.C., in Atlanta, GA.
Even with all the media attention that melanoma has gotten over the years, many people still don’t think to check these particular areas of the body when conducting a monthly self-exam, especially if they are dark skinned.
Though Caucasians can get nail as well as palm and sole melanoma, this cancer is more common in those with dark skin.
The brown band or streak in a nail, plus the dark patches on the sole of a foot or palm, “may be mistaken for trauma (hemorrhage under the skin, which may look very similar to pigment to the naked eye) or benign lesions,” says Dr. de Golian.
“If caught early, just like any melanoma, nail apparatus melanomas have a very good prognosis, but if the melanoma is not identified early and continues to grow, the prognosis may become worse.”
Melanoma of the nail unit is also called subungual melanoma.
“About 5% of all melanomas are acral lentiginous melanomas, and while they may affect any racial group, African-American and Asian individuals are more likely to develop this type of melanoma since sun related melanoma elsewhere on the skin is less likely in these groups.
“Any person with a new brown, black, asymmetrical spot on the palms, soles or around the nail, as well as new brown linear streaks under the nail plate itself, should seek evaluation with a board certified dermatologist.
“Untreated melanoma may metastasize to other parts of the body and could be life threatening if it continues to grow.
“The truth is this potential killer can occur anywhere on the skin, even in non-sun exposed areas,” such as inside the nose and mouth.
When melanoma is caught early, including subungual, the prognosis is excellent.