Subungual Melanoma

Melanoma is the name for any cancer that develops in the body’s melanocyte cells, which are cells that create the pigment that gives color to a person’s skin, nails and hair. Subungual melanoma is a rare type of cutaneous malignant melanoma, which is the term used to describe melanoma that affects the skin. Subungual, or nail, melanoma occurs in the skin underneath a fingernail or toenail. In 75% to 90% of cases, it affects the thumbnail or big toenail.

While the exact causes of subungual melanoma are not yet fully understood, there are certain risk factors that make it more likely someone may develop the condition. These include:

• Having darker-colored skin, which may lead to a delayed diagnosis
• Being older than age 50
• Frequently injuring the fingernails or toenails

To diagnose subungual melanoma, doctors may recommend a variety of tests and screening procedures. These might include:

• A physical examination of the affected nails by a board-certified dermatologist
• Gathering information about a patient’s medical history, including any risk factors for nail melanoma
• Onychoscopy, which is the term for an examination of the nails using a dermoscope – a magnifying tool that allows a doctor to see the nails in more detail
• Biopsy of the nail and nail bed, which involves surgically removing the nail and any tissue underneath it, then examining this tissue in a lab for signs of cancer
• A sentinel lymph node biopsy, which is a procedure that can tell whether cancer has spread to the body’s lymphatic system by removing a tissue sample from lymph nodes

Subungual melanoma is staged in a similar way to most other forms of melanoma. Staging is the process of determining how advanced a cancer is and assigning it a number, usually from 1 to 4, with higher numbers indicating that the cancer is at a more advanced stage. 

Learn more about the melanoma stages.

How Fast Does Subungual Melanoma Grow?

Subungual melanoma is a slow-growing type of melanoma. It can take months or longer for the condition to spread or for any signs of the disease – like black lines on the nails – to become larger or change shape.

For patients with subungual melanoma, which treatment options are best depends on a variety of factors, including the cancer’s stage, whether it has spread beyond its original site and the patient’s overall health. However, common treatments for subungual melanoma include:

• Surgery to remove the nail, nail bed and a small amount of healthy tissue around it (referred to as a margin)
• Treatment with certain advanced surgical techniques like Mohs surgery, which are less invasive and offer better cure rates than some conventional surgeries
• Amputation of an affected finger or toe
• Targeted therapy, immunotherapy or other options for patients with advanced subungual melanoma that has spread to distant parts of the body

People who are diagnosed with subungual melanoma receive specialized care from a multidisciplinary cancer care team that often includes:

• Dermatologists, who are doctors with expertise in skin health and a wide range of skin conditions
• Mohs surgeons, who are specially-trained surgeons who act as the pathologist and surgeon and can provide real-time analysis of the margins
• Surgical oncologists who are specialty-trained in advanced surgical techniques for treating a wide range of melanomas
• Medical oncologists with expertise in using conventional and novel medications to treat cancer
• Trained oncology nurses, who work alongside a patient’s cancer care team to provide expert care before and during treatment
• Supportive care specialists, who offer services that support each patient’s physical, mental and social health during and after treatment

Survival rates for subungual melanoma are believed to be similar to the survival rates for melanoma in general. One study noted that the five-year survival rate for subungual melanoma varied from 16% to 87%, depending on how far the disease had spread.

It’s important to speak with the care team to get a personalized subungual melanoma prognosis based on the patient’s cancer subtype, stage and overall health.