Subungual melanoma is a form of cancer that affects the nails, wherein subungual implies “beneath the nailbed” in medical terminologies. This type of cancer is quite rare and is characterised by brown or black bands appearing prominently on the nails in hands and feet, along with bleeding in the region and weak, damaged tissues. Subungual melanoma is fundamentally different from melanoma, which is a form of skin cancer that arises in melanocytes – skin cells that contain pigments. Melanoma is a perilous type of skin cancer that can spread rapidly to other organs, in which distinct moles appear on the face, neck, arms – parts of the body exposed to harmful UV rays, direct sunlight for extended periods of time.

Also Read: Melanoma: Causes, Symptoms And Treatment
Subungul Melanoma Thumbs
In subungual melanoma, the uncontrolled proliferation of cells and tumour growths begin in the nail matrix - the portion where keratin is present and which acts as a protective covering for the layer of skin below. Although this type of cancer occurs only in seldom instances, it is important to report the symptoms as soon as they are noticed on the nails. In many cases, subungual melanoma resembles an injury or bruise on the nails, so it is vital to get it examined by a medical expert at once. This helps in prompt, accurate diagnosis and timely medical treatment of subungual melanoma, to avert the spread of cancer to other organs in the body.

Causes Of Subungual Melanoma

The exact cause of subungual melanoma had not been identified, but medical researchers, doctors, scientists have determined certain factors that trigger this rare cancer originating in the nail matrix. These include:

  • Severe injury, damage, trauma to the nails, which is the major instigating issue for this cancer to develop in the nails
  • Having close family members with subungual melanoma
  • Genetic aberrations, like suffering from a pre-existing inherited condition of Xeroderma pigmentosum
  • Possessing a vulnerable immune system, such as in autoimmune diseases of Lupus, HIV-AIDS


Although the distinguishing signs of subungual melanoma can emerge in all ten fingernails, as well as all ten toenails, it predominantly surfaces in the thumb nails and big toes, generally afflicting only a single nail at a time. Moreover, this kind of cancer in the nails affects mostly middle-aged adults and the elderly, with dark-skinned individuals being more at risk.

The typical symptoms of subungual melanoma consist of:

  • “Hutchinson’s Sign” – a defining streak that develops in the tip of the nail and expands down to the nailbed and enters the cuticles
  • Brownish or deep black stripes in the nails even with no accidental injury
  • Prominent lines on the nails that tend to become larger and spread all over the area
  • Pigmentation in the nails which expands to neighbouring skin tissues
  • Bruises, wounds in the nail which do not mend even after applying ointments
  • Bulges and nodules which grow under or on the nails
  • Bleeding in the nails with discolouration and swollen masses
  • Damage to the nail plate, with brittle, cracked nails


The doctor initially investigates the damaged nail and questions the patient about any trauma, injuries that they might have experienced, to probe if that could be the cause of subungual melanoma. They also quiz the affected person about the nature of the lesions and streaks, when they first noticed the discolouration, lumps and if those marks have changed or become bigger over time. Subungual melanoma is often mistaken for fungal infections, which also present with dark blue, brown or black pigmentation in the nails. Hence it is necessary to consult with a healthcare professional as soon as any signs of abnormal growths, discoloured spots, lines are observed on the nails.

Also Read: Fungal Nail Infection: Causes, Symptoms And Treatment

If the medical expert is doubtful that the symptoms witnessed in the nails of the patient could be a sign of subungual melanoma, they perform a biopsy, wherein a sample of tissue is carefully excised from the nail bed and nail matrix. This nail segment is then analysed in a microscope to detect the presence of cancer cells and confirm the instance of subungual melanoma.


The treatment for subungual melanoma depends on how much damage has been induced in the nail and finger/toes, as well as if the cancer is restricted only to the nail portions or has spread to other parts of the body.

If subungual melanoma is detected only in a segment of the nail, then just the entire nail is surgically removed. But if the cancer has extended to the surrounding vicinities of the skin, then a fraction of the finger or toe itself is eliminated by surgery. In very rare circumstances, where subungual melanoma has metastasized to other organs, tissues in the body, such as the lymph nodes, lungs, skin, then advanced medical treatment is required. This involves radiation therapy, chemotherapy to target, destroy the cancer cells in various organs in the body.