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VERIFIED CONTENTAuthor: Katarzyna Wieczorek-Szukała, MD, PhD, medical biotechnologist, Medical University of Lodz

Melanoma is usually associated with a skin cancer that appears as birthmarks and moles on the body. It turns out, however, that there is also a type of melanoma, which may appear as a dark discoloration or stripe under the fingernail or toe nail. Often confused with a hematoma, diagnosis is too late in many cases. Concerns arose that the risk of subungual melanoma may be directly related to the performance of hybrid manicure.

Subungual melanoma (MS) is a rare type of melanoma, accounting for only 0.7 to 3.5% of all cases. It is a malignant tumor formed of melanocytes, i.e. skin pigment cells.

In general classification, melanomas are classified into four basic types:

  • Superficial spreading melanoma (SSM)
  • Lentigo maligna melanoma (LMM)
  • Nodular melanoma NM
  • Acral melanoma (ALM)

In histopathological terms, nail melanomas belong to the latter group. Unlike superficial spreading melanoma (SMM) and lentigo melanoma (LMM), these lesions progress more quickly, which may result in a greater likelihood of metastasis.

Nail melanoma - causes

Chronic sun exposureis considered to be the main factor that directly influences the formation of skin cancers, including most melanomas. UVA and UVB rays, penetrating into the deeper layers of the skin, damage human DNA, causing the formation of oncogenic mutations, i.e. mutations that may lead to the development of cancer in the future.

It seems, however, that the negative effects of the sun do not play such an important role in the formation of nail melanoma, because it is the nails that have an effective protective function.

It has been proven that the keratin plate completely blocks UVB radiation, and allows only 0.5 to 2.5% of UVA to pass through, preventing the rest of the spectrum from penetratinglayers of the matrix and nail bed.

Zanail melanoma risk factorsconsidered:

  • mechanical trauma,
  • immune disorders or chronic infections,
  • dark skin phenotype (especially in African-American races),
  • old age.

In recent years, there have also been reports of an increased risk of nail melanoma in people who regularly perform gel or hybrid manicure. The lamps that are used during these treatments to harden the varnish actually emit UV radiation. Independent groups of scientists have proved, however, that there is no clear evidence of the harmfulness of this type of cosmetic treatment, and the dose of UV radiation taken during one session is comparable to that received by our hands during … a walk on a sunny summer day.

Currently, before the planned hybrid manicure, it is recommended to protect the skin of the hands with a cream with a UV filter.

Nail melanoma - symptoms

Subungual melanoma is mainly visible in pigmentary changes, i.e. disturbed melanin deposition in the skin. In most cases of this neoplasm, there is one or more long brown or black stripes under the nail. These changes begin at the matrix, i.e. the base of the plate, and run along the length of the nail. More rarely, they take the form of transverse stripes, triangular changes or spots resembling a dark traumatic hematoma. As the disease progresses, redness, pain, splitting of the nail plate, ulceration and a generalized inflammatory process may occur.

Unfortunately,these symptoms are very easy to confuse with a bacterial or fungal infection, a wound resulting, for example, after a bruise or the action of chemicals . Pigmentation changes may also occur as a result of many systemic diseases, e.g. primary adrenal insufficiency (Addison's disease) or copper metabolism disorders (Wilson's disease).

Nail melanoma - diagnosis

Due to the lack of specific symptoms, correct diagnosis of nail melanoma is a challenge even for doctors.

For diagnostics, special guidelines (the so-called ABCDEF algorithm), developed by Dr. Levit and colleagues, are used, which are a set of features characteristic for melanoma in the area of ​​the nail. These are:

  • A: Age between 50 and 70 years
  • B: (Band, Breadth and Blurred boarder) presence of a brown-black stripe on the nail with a width of more than 3 mm and irregular borders
  • C: (Eng. Change)rapid growth and changes in the shape of the pigmented lesion
  • D: (Eng. Digit) location on the thumb, index finger or toe
  • E: (Extension) gradual expansion of the pigmented lesion onto the tissues surrounding the nail (the so-called Hutchinson symptom)
  • F: (Eng. Family) occurrence of melanomas in the family

When assessing a suspected birthmark, dermatoscopy is usually used, i.e. a microscopic method that allows for accurate and non-invasive verification under multiple magnification and intense lighting. Correct assessment of the results of a dermatoscopic examination is not easy and requires extensive experience from a specialist.

Useful are special guidelines, created individually for the diagnosis of nail melanoma, the so-called CUBED rule:

  • C: (colored lesion where any part is not skin color) the birthmark has a different color than the patient's skin
  • U: (ang. Uncertain diagnosis) uncertain diagnosis
  • B: (Bleeding lesions on the foot or under the nail, whether the bleeding is direct bleeding or oozing of fluid. This includes chronic "granulation tissue") bleeding birthmark under the nail of the foot or hand, including chronic granulation tissue
  • E: Enlargement or deterioration of a lesion or ulcer despite therapy
  • D: (Delay in healing of any lesion beyond 2 months) delayed physiological healing for more than two months

The final diagnosis is made on the basis of a biopsy and the collection of tissue from under the nail along with a pigmented lesion for histopathological examination. If an advanced tumor is found, a clinical evaluation of the surrounding lymph nodes will also be performed to help determine if the tumor has spread. Only on the basis of the above results, a further treatment plan is established.

Nail melanoma - treatment

The primary treatment of nail melanoma is primarilycomplete removal of the nail , along with the bed or matrix. The resection margin is determined by the stage of the tumor. Sometimes radical treatment may be necessary - i.e. amputation of the phalanx at the joint level. If cancer has metastasized to other organs, it may be necessary to remove local lymph nodes (so-called lymphadectomy), as well as complementary chemo-, radio-, or immunotherapy.

The prognosis for nail melanoma depends on how early it is diagnosed and removed. Therefore, any disturbing, poorly healing lesion should be consulted with a dermatologist.

KuAs a warning, it is worth giving the example of one of the most famous patients suffering from nail melanoma - the legendary reggae musician Bob Marley. The tumor was detected in him at the age of 33 under the nail of the big toe. A professed Rastafarian who professed the principle of unity of the body, Marley refused to have his finger amputated. The progressive disease led to extreme exhaustion of the body and the formation of metastases in the liver, lungs and brain. The cult artist died just three years after the cancer was discovered.

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