Melanomas are the most serious type of skin cancer. However, melanoma also shows up in unusual places. Doctors often call them hidden melanomas because they are found in places you don't normally expect or check.
Eye. Although rare, melanoma can occur in the middle of the three layers of the eye, called the uvea or uveal tract, which includes the iris (colored area), ciliary body (muscles that change size of pupil and shape of lens) and choroid (blood vessels that feed the eye). This type of melanoma is called ocular, intraocular or uveal melanoma. Although ocular melanoma sounds ominous, physicians can cure it if it hasn't spread and save the patient's vision.
Ocular melanoma may not produce symptoms. When it does, patients find a dark spot on the iris, their pupil changes shape or their vision becomes blurred. Risk increases with age and in people who are fair skinned with blue or green eyes.
Patients with uveal melanomas and their first-degree relatives are at higher risk for developing other malignancies, especially colon cancer. Women are also at a somewhat higher risk for breast cancer.
Basal cell carcinoma, which accounts for 80 percent of non-melanoma skin cancers, can also occur on the eyelid. It rarely spreads and the prognosis is good when treated.
Ear. Melanoma of the ear accounts for seven to 20 percent of all head and neck melanomas. Males are more likely to develop ear melanomas because of their hairstyles, habits and exposure to ultraviolet radiation. If caught early, the three and five year survival rates are extremely high.
Nail bed. Also called subungal ("under the nail"), melanoma can occur under the toe or fingernail. A streak in the nail or an area that appears bruised can be a sign of subungal cancer. Fortunately, it's usually benign.
Mucosal tissue. Mucosal tissue lines sensitive organs, such as the nose and mouth. By the time mucosal tissue melanoma is diagnosed, it's usually advanced. These melanomas truly are hidden as they occur in areas we can't see.
Symptoms of mucosal tissue melanoma include:
- Nose: nosebleeds or stuffiness
- Mouth and nasal cavity: pigmented mass or pain when swallowing, inflammation of the inner ear
- Female genitals: discharge, bleeding, itching and pain
- Anus: rectal bleeding, painful rectal mass
- Urinary tract: blood in urine or difficulty urinating
- Esophagus: trouble swallowing, regurgitation, pain, bleeding
Ultraviolet radiation is the primary risk factor for melanomas. To reduce your risk of melanoma, limit your sun exposure, use sunscreen and wear protective clothing and sunglasses.
Sources
http://www.treatnailfungus.org/Symptoms/melanoma-of-toenail.html
http://www.skincarephysicians.com/skincancernet/hidden_melanomas.html
http://www.medscape.com/viewarticle/556395
http://www.medscape.com/viewarticle/556958
