Melanoma 101: Introduction to a Deadly Skin Cancer

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Melanoma facts

  • Melanoma is a cancer that develops in pigment cells called melanocytes.
  • Patients themselves are the first to detect many melanomas.
  • Caught early, most melanomas can be cured with relatively minor surgery.
  • Melanoma can be more serious than the other forms of skin cancer because it may spread (metastasize) to other parts of the body and cause serious illness and death.
  • Spots suspicious for melanoma usually show one or more of the following symptoms and signs (the ABCDs):
    • Asymmetry,
    • Border irregularity,
    • Color changes or too many colors in one mole,
    • Diameter more than 6mm (the size of a pencil eraser).
    • Some now add a fifth letter: E for Evolving, or changing over time.
  • Elevated risk factors for melanoma include Caucasian (white) ancestry, fair skin, light hair and light-colored eyes, a history of intense sun exposure, close blood relatives with melanoma, and moles that are unusually numerous, large, irregular, or "funny looking."
  • Malignant melanoma in situ refers to a very thin superficial spreading melanoma that does not extend beyond the outermost layers of skin.
  • Doctors diagnose melanoma by performing a biopsy in which they remove a piece of skin for analysis. Whenever possible, it is best to remove the entire lesion in question.
  • The most common forms of melanoma are superficial spreading melanoma, nodular melanoma, and lentigo maligna.
  • Treatment of melanoma is primarily by surgical removal.
  • Changing or suspicious spots on the skin should be brought to medical attention right away.

What is melanoma?

Melanoma is a cancer that develops in melanocytes, the pigment cells present in the skin. It can be more serious than the other forms of skin cancer because it may spread to other parts of the body (metastasize) and cause serious illness and death. About 50,000 new cases of melanoma are diagnosed in the United States every year.

Because most melanomas occur on the skin where they can be seen, patients themselves are often the first to detect many melanomas. Early detection and diagnosis are crucial. Caught early, most melanomas can be cured with relatively minor surgery.

This article is written from the standpoint of the patient. In other words, instead of describing the disease in exhaustive detail, the article focuses on answering the questions: "How do I know if I have melanoma?" and "Should I should be checked for it?"

Spots on the skin

Guideline # 1: Nobody can conclusively diagnose him- or herself. If someone sees a spot that looks as though it is new or changing, he or she should show it to a doctor. When it comes to spots on the skin, it is always better to be safe than sorry.

Everybody gets spots on their skin. The older we are, the more spots of different types we have. Most of these spots are benign. That means they are neither cancerous nor on the way to becoming cancerous. These may include freckles, benign moles, collections of blood vessels called cherry angiomas, or raised, irregular bumps on the skin called seborrheic keratoses that appear to be stuck on to the skin.


Guideline # 2: The vast majority of moles stay as moles and do not turn into anything else. Most melanomas do not arise in preexisting moles. For that reason, having all of one's moles removed to "prevent melanoma" does not make sense.

Some people are born with moles (the medical name is "nevus," plural "nevi"). Almost everyone develops them, starting in childhood. On average, people have about 25 moles, though some have fewer and others many more. Moles may be flat or raised, and they may range in color from tan to light brown to black. Moles may lose their color and end up flesh colored. It is unusual to develop new pigmented moles after age 35.

Medically Reviewed by a Doctor on 2/3/2016

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Melanoma (Skin Cancer) - Symptoms Question: What did your melanoma look like when you first noticed it? What was the size of the growth?
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Get information about skin changes that may indicate you have skin cancer.

Skin Changes: How to Spot Skin Cancer

According to the American Academy of Dermatology, one in five Americans will develop some form of skin cancer in their lifetime. Skin cancer is the most common type of cancer in the U.S. Sun exposure is the leading cause of skin cancer, and people with fair skin and light eyes whose skin has a tendency to burn easily in the sun are most susceptible to the damaging effects of the sun's UV rays.

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