Just as the skin is, the nail unit is susceptible to cancer. However, nail cancer occurs much less frequently than skin cancer does. The location in the nail unit most likely to develop a malignant growth is the nail bed or the “skin line” structure underneath the nail plate, the latter being the site on which nail polish is placed.
There are three main types of cancer that may involve the nail bed. They include basal cell carcinoma, and malignant melanoma. All three also occur on the skin, but unlike the skin where basal cell carcinoma is the most common, squamous cell carcinoma affects the nail most often.
Second in frequency is the malignant melanoma, while basal cell carcinoma is third. Malignant melanoma has the potential for being the most serious, whereas the basal cell carcinoma is the least serious.
When a malignant growth involves the nail, it usually occurs on a single finger. A wide range of signs and symptoms may occur as a manifestation of cancer of the nail unit (see sidebar). Should any of these changes appear, especially if only one nail is persistently and consistently involved, it is essential that medical attention be obtained. This is particularly true if the affected fingernail or toenail has not healed for several weeks or more. Your client’s physician will perform a number of diagnostic tests to determine the problem with her nail. If he does not do these himself, he will refer your client to an appropriate specialist, such as a dermatologist. These tests may include a potassium hydroxide wet mount or slide smear for fungus and a culture for infection by bacteria, viruses, and fungus. In addition, it may be necessary to do an x-ray and a biopsy in order to arrive at a definite diagnosis. If the presence of a nail unit cancer is confirmed, then some form of surgical treatment will be required. The type and extent of surgery will depend on the type and severity of the cancer. Radiation and chemotherapy are not often used for nail cancer although the latter may be necessary in more advanced cases. Fortunately, however, the outlook for full recovery is good provided the diagnosis is made reasonably early.
The cause of nail malignancies is not really known although some factors may play a role. Overexposure to the sun may affect the nail as it does the skin, but to a somewhat lesser degree. Trauma or injury has been said to be a factor but definite proof of this is lacking. A brown mole or birthmark in the nail matrix, under the cuticle skin area, may precede malignant melanoma.
In summary, any non-healing disorder of the fingernail or toenail should be investigated by your client’s physician in order to make a definite diagnosis and rule out the presence of cancer of the nail unit.
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