Melanoma is a type of skin cancer that begins in melanocytes – the cells that produce the pigment melanin that colors the skin, hair and eyes. Melanocytes also form moles, where melanoma often develops. Melanoma is the most dangerous form of skin cancer. Melanoma is usually the result of DNA damage caused by ultraviolet radiation from sunshine or tanning beds, but genetic defects also can trigger melanoma to develop.

Overview and Symptoms

The typical sign of melanoma is a mole that takes on several of these characteristics, known as the ABCDEs of melanoma:

  • A – Asymmetry: Melanoma lesions usually have an irregular shape. Benign moles are usually symmetrical.
  • B – Border: Melanoma lesions generally have irregular borders. Benign moles have smooth, even borders.
  • C – Color: Melanoma lesions may show more than one color (blue, black, red, tan, etc.) or an uneven distribution of color. Benign moles are usually a single shade of brown or tan.
  • D – Diameter: Melanoma lesions are often greater than 6 millimeters in diameter (approximately the size of a pencil eraser).
  • E – Evolution: Melanoma lesions will evolve significantly in relatively short periods of time. Benign moles change only slightly over long periods of time.

Melanoma Diagnosis

If you have irregular moles that contain the above characteristics, it’s important to see a dermatologist. Ultimately, the only way to diagnose melanoma is through a skin biopsy. The mole in question will be removed and sent to a pathologist for review under a microscope to check for cancer cells.


Early-stage melanoma usually can be treated with surgery alone. However, if your melanoma has advanced it will require additional treatment. Melanoma treatment may include:

  • Surgery to remove the skin cancer tumor and a small margin of healthy tissue around it
  • Radiation therapy – the use of focused, high-energy x-rays to kill cancer cells or keep them from growing
  • Chemotherapy – the use of drugs to stop cancer cells from multiplying in the body
  • Photodynamic therapy – the use of medications, called photosensitizing agents, and light to kill cancer cells
  • Targeted therapy – the use of drugs or other substances to more precisely identify and attack the cancer cells or genetic mutations specific to your tumor sub-type
  • Biologic therapy – the use of vaccines or bacteria to stimulate the body's immune system to act against cancer cells; at BIDMC, through our Biologic Therapy Program, we use biologic agents such as cytokines and vaccines to treat patients with advanced melanoma.

Cancer Center

The Melanoma and Skin Cancer Program at BIDMC's Cancer Center provides leading edge care for patients with all types of skin cancer.

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