Melanoma is the most dangerous form of skin cancer.  Found early, most melanomas are curable, however, left undetected, the disease can spread to other parts of the body making it harder to treat, and potentially fatal.

Experts advise giving self-exams once a month to check for changes in the patterns of moles and other marks on your skin as well as the appearance of new markings. Melanoma generally takes time to grow on the outermost layer of skin, the epidermis. If diagnosed before spreading to the next layer of skin (the dermis) melanoma is much easier to treat and cure.

It can often be hard to tell the difference between normal moles and unhealthy markings. Red flags typically involve changes in size, shape, or color; discolorations; and moles that bleed easily.

Remember Your ABCs

The American Cancer Society describes a normal mole as an “evenly colored brown, tan, or black spot, generally less than 6 millimeters (about the width of a pencil eraser).”

A generally-used rule of thumb is the ABCDE system for finding tell-tale signs of melanoma. As the American Cancer Society points out, you’re essentially looking for any spot on your skin that stands out as odd and different. Formerly known as the ABCD system, it was recently updated to include a fifth standard in measuring melanoma risk. You can refer to the ABCDE guide to check your skin for warning signs.

  • Asymmetry: one half of a mole or birthmark does not match the other half.
  • Borders: irregular, ragged edges of a mole.
  • Color: irregular color, ranging from shades of black, brown, or tan (sometimes pink, white, red, or blue) within one sore. A normal mole tends to have an unvarying brown color.
  • Diameter: the spot is typically (not always) larger than 6 millimeters in diameter—the size of a pencil eraser.
  • Evolving: this is a new addition to the former ABCD list; it acknowledges that if a mole changes—in any way—this is good cause to see your doctor.

If you notice any suspicious growths, sores, or lumps on your body, see your doctor as soon as possible. Your doctor will examine your body for the appearance of the marking. If your doctor suspects melanoma, he or she may take a biopsy, a sample of skin to view under a microscope—removing a small area or the entire growth—to confirm the diagnosis.

If your doctor determines a melanoma diagnosis, it is important to understand how you will proceed.

Questions you may want to ask include:

  • How far has my melanoma spread?
  • Are there any additional tests before we begin treatment?
  • What are my treatment options?
  • What are the risks and side effects associated with these treatments?
  • How long will treatment last?
  • Will I have a scar following the treatment?
  • Are my family members at risk for developing melanoma?
  • What are the chances of my cancer returning?

Thanks to advances in technology and ongoing research, more and more tools are available to educate and assist individuals in diagnosing melanoma. —a combined effort of NCI, the University of Pennsylvania, and the University of California, San Francisco—is an online interactive feature that helps doctors determine who is most at risk for developing melanoma. Pulling data from a case-control study of non-Hispanic whites in the United States, the calculator is intended for health professionals but could serve as a helpful tool for curious and concerned patients. Based on a series of questions, including age, gender, complexion, and race, the tool calculates an individual’s five-year melanoma risk.  

What It Means: In Situ vs. Invasive

If your doctor describes the melanoma as in situ this indicates melanoma that remains on the outermost layer of your skin (epidermis) and is in one area. A diagnosis of invasive melanoma describes a more serious condition, in which the tumor has spread more deeply into the skin or to other organs.