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What is Melanoma?

Melanoma is a type of skin cancer. It happens when the cells that give skin its color, melanocytes, get damaged. The damaged cells grow quickly and form a cancerous tumor.

Melanoma is curable when it is found early and removed. If it is not treated, the cancer can spread to other parts of the body. If this happens, melanoma can cause death. Melanoma is the most dangerous of all the skin cancers.


Usually, the first symptom is a skin tumor that looks like a mole. The mole is usually black or brown, but can be pink, red, white, blue, or skin color.

Moles and other marks on the skin are usually harmless. Use the “ABCDE” method to see if a mark is a harmless mole or melanoma:

  • Asymmetry. A harmless mole usually looks the same on both sides if you were to split it down the middle. Melanoma will look different on one side.
  • Border. A harmless mole usually has a smooth and clear border all the way around it. Melanoma has fuzzy, uneven, or notched edges.
  • Color. A harmless mole is all one color (usually brown or tan). Melanoma can be made up of different colors. It can have different shades of brown or tan, or have black, blue, white, red, pink, or skin color mixed in.
  • Diameter. This is about the mole’s size. A harmless mole is usually no bigger than a pencil eraser. Melanoma is often larger than this. But if you see a small mole that has asymmetry, a fuzzy border, and multiple colors, you should still get it checked out.
  • Evolving. Harmless moles usually stay the same, but melanomas can change shape, size, or color as time goes on.

You might also notice a sore that doesn’t heal or some new swelling or tenderness near a mole. You know your skin best, so you are the best person to tell if a mole has changed.

When to See a Doctor

See a doctor if you notice any mole or mark that has any of these characteristics. You may also want to see a doctor if you have 100 or more moles (even if they are harmless) because you are at a greater risk for melanoma.

Risk Factors

Melanoma is damage to the skin cells, usually because a person was exposed without protection to intense ultraviolet (UV) light. In most cases, the sun is the source of the UV light. But it can come from tanning beds or, in some cases, UV treatment for another condition, such as psoriasis.

Diagnosis and Tests

  • Visual exam. The doctor will look at your moles and skin marks to see if they have any of characteristics of melanoma.
  • Biopsy. The doctor will remove some or all of the mark and the lab will look at the cells to see if it they are cancer cells. The doctor will use a local anesthetic to numb the skin before the biopsy so you don’t feel any pain. There are a few different types of biopsy. For a shave biopsy, the doctor just takes the top layers of the mark. For a punch biopsy, the doctor takes a sample of all the layers of skin with a small round cutting tool like a cookie cutter. For an incisional biopsy, the doctor uses a surgical knife to cut out part of the mark with all layers of the skin. An excisional biopsy is similar, except that the doctor removes the whole thing.


Treatment of melanoma depends on three things:

  • Size and location of the tumor, and how fast it’s growing
  • Whether the cancer has spread to lymph nodes near the tumor
  • Whether the cancer has spread to other parts of the body (metastasized)

Melanoma that is limited to the tumor (mark) on the skin can be removed. Often, it can be removed right in the doctor’s office. The goal is to remove the entire tumor and keep as much of the healthy skin as possible. The doctor will remove the tumor along with a margin of healthy skin.

If the margin shows any sign of cancer, you will need to have more skin surgery. The doctor will preserve as much of your healthy skin as possible.

If the cancer has spread to lymph nodes (part of the immune system) or other parts of the body, you may need cancer treatments including surgery, radiation, chemotherapy, and immunotherapy. Your treatment decisions will depend on the stage of the cancer, the chances that treatment will help, the side effects, and your preferences about the benefits and tradeoffs.


There is no sure way to prevent melanoma, but you can lower your risk:

  • Avoid the sun or stay in the shade, especially when the sun is strongest, between 10 a.m. and 2 p.m.
  • Use sunscreen when you are out in the sun.
  • Cover up in the sun. Wear a hat and sunglasses, and cover up with a shirt.
  • Avoid tanning beds and sun lamps. These increase the risk of melanoma, especially when they are used before the age of 30.