While most people associate the word “melanoma” with moles and tanning, it’s actually not just a kind of skin cancer. Melanoma is most often found on the skin, yes, but it also can form in the eyes or in mucous membranes. So what’s the connecting thread here?
As it turns out, melanoma is a cancer of melanocytes—the cells that produce the pigment melanin (not to be confused with the sleep-inducing melatonin). Melanin is responsible for giving skin (including mucous membranes) and eyes their color, so if melanocytes mutate in any of these areas, that’s where you may develop cancer.
Mucus what?
Mucous membranes are body cavities that connect to the outside—such as the mouth, nose, windpipe, stomach, and female genital tract. These membranes often secrete mucus—which is why they’re referred to as mucous, meaning mucus-producing.
Mucosal melanoma is pretty rare; it makes up around 1% of all melanoma cases. Of this 1%, 50% begins in the membranes of the head and neck, 25% in the ano-rectal region, 20% in the female genital tract, and 5% in other mucous membranes.
However, this type of melanoma is not considered to be related to UV exposure—it actually has no identified risk factors, not even genetic inheritance. Similarly, it’s fairly hard to diagnose, as it’s often located in places where the sun don’t shine and can be confused for hemorrhoids.
Eyes
Ocular melanoma, while a rare type of melanoma, is the most common primary eye tumor in adults. Around 2,000 new diagnoses are made yearly, with risk factors including pale skin color, exposure to UV light, and several gene mutations (most often ones known as GNAQ and GNA11). If left untreated, ocular melanoma often spreads (metastasizes) to the liver. Wearing UV-protected sunglasses year-round is an easy way to lower your risk.
Skin
Cutaneous melanoma is the most deadly form of skin cancer—although with a five-year survival rate of 91.5%, it’s far from a death sentence. Cutaneous melanoma is found on the skin, which includes the palms of hands, the scalp, between toes, and underneath nails. Risk factors include being white, a history of burning, having many moles, family history, and of course UV ray exposure.
Like other cancers, melanoma is most deadly when it isn’t caught early, so preventative measures and frequent body-checks are key. A step-by-step guide for skin checks can be found here.
(Image credit: Thinkstock)
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