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Melanoma

Medically reviewed by: Andrew W. Walter, MD

What Is Melanoma?

Melanoma (mel-eh-NOE-muh) is a type of cancer that begins in a melanocyte (meh-LAN-uh-site), a cell in the top layer of skin (the epidermis). Melanocytes make melanin (MEL-eh-nun), the pigment that gives skin its color.

Melanoma also can develop in other parts of the body, like the eyes, mouth, genitals, and anal area.

What Are the Signs & Symptoms of Melanoma?

Often, melanoma begins as a mole or a bump on the skin. It's important to know if a mole has changed in size, shape, or color.

Keep this ABCDE rule in mind when checking moles:

  • A for asymmetry: If you were to cut the mole down the middle, would the left and the right sides look different?
  • B for border: Are the edges blurry and undefined? Does it look like it's spreading sideways?