What is Subungual Melanoma?
Melanoma is a malignancy of the skin that originates in the melanocytes. These are cells that have skin pigments. It is a collection of these melanocytes that forms the basis of melanoma. However, all growths of melanocytes are not cancerous. As is the case with all cancers, early diagnosis and treatment is the key for a good prognosis and to prevent the spread of cancer to other organs of the body.[1,2,3]
The primary cause of melanoma is believed to be excessive exposure to ultraviolet rays of the sun. Thus melanoma mostly presents on the exposed areas of the body where sunlight hits them directly. However, sometimes melanoma can also develop in other areas. One such area is under the fingernails. Melanoma developing under the fingernails is what is termed as Subungual Melanoma. What makes this condition challenging is that it looks quite similar to a normal bruise in the fingernails.[1,2,3]
Subungual Melanoma originates in the nail matrix from where keratin comes from. Research suggests that approximately 1.5% of all confirmed melanoma cases are Subungual Melanoma.[1,2,3]
What Causes Subungual Melanoma?
As is the case with melanomas, excessive sunlight is not the only cause for Subungual Melanoma even though it is a definite risk factor. This is because it develops under the nail in the nail matrix from where the keratin originates. There have been no identifiable causes for it but there are certain risk factors that increase the likelihood for getting this condition.
People who are dark in complexion are at an increased risk for developing Subungual Melanoma. People who are above the age of 50 also are at an increased risk for developing Subungual Melanoma. People who have a history of trauma or injury to the fingernails or toenails can also at times develop Subungual Melanoma.
What are the Symptoms of Subungual Melanoma?
The symptoms of Subungual Melanoma begin with the appearance of a brownish black streak beneath the toenail or fingernail. This often at times is mistaken for a bruise or an injury. This streak will almost always not have a known cause. These streaks then start to gradually increase in size with time. This “bruise” or streak does not heal on its own.[2,3]
The fingernails then get separated from the nail bed. The skin around the nail also gets darker and discolored. There may be at times bleeding from the nail or development of a nodule. The nail plate may get cracked, dry, and thin.[2,3]
However, the most telling symptom of Subungual Melanoma is called the Hutchinson’s Sign. In this, there will be a streak that will start at the top of the nail and extend right into the cuticle passing through the nail bed. In majority of the cases, Subungual Melanoma occurs either in the thumbnail or the big toenail even though this condition can develop in any nail.[2,3]
There have also been cases where a person is diagnosed with Subungual Melanoma but does not have any streaks or Hutchinson’s Line. In such situations, there will be other symptoms explained above that will be observed.[2,3]
How is Subungual Melanoma Treated?
The treatment of Subungual Melanoma depends on the extent of the disease. Once the extent is determined then in most cases a surgery will be required to remove the diseased portion. The surgery may involve either removal of the entire finger or a part of it. In case the cancer has spread to lymph nodes then surgery may not be enough to treat the condition. In such cases, further treatments in the form of radiation and chemotherapy will be required to prevent any further spread of the cancer.[2,3]
Radiation however is a just palliative measure and curative. The New England Journal of Medicine states that it takes approximately 2 years for a confirmed diagnosis of Subungual Melanoma since the onset of symptoms. However, if a person has telltale signs of Subungual Melanoma and is suspicious then it is imperative to get an early diagnosis done.[2,3]
The prognosis of Subungual Melanoma is generally not good when compared to other forms of melanomas. This is mainly because of the delays in the diagnosis of the condition. Speaking about the 5-year survival rate of people with Subungual Melanoma, the numbers are significantly variable and range from 15-86% depending on how severe the disease is and the spread of the condition.[2,3]
If the cancer is detected early and treatment is given then the chances of survival is very good. The overall prognosis depends on how early the diagnosis is made and how early the treatment starts. As a thumb rule, early the detection the more are the chances of survival in a person with Subungual Melanoma.[2,3]