Melanoma and Skin Cancer Program

Biopsy and Diagnosis

Often, the first sign of melanoma is a change in the size, shape, color, or feel of an existing mole. Other times, melanoma appears as a new spot on the skin. It may be black, abnormal or "ugly looking." If you have a question or concern about something on your skin, see your doctor.

Thinking of "ABCDE" can help you remember what to watch for:

  • Asymmetry - the shape of one half does not match the other
  • Border - edges are often ragged, notched, blurred or irregular in outline; the pigment may spread into the surrounding skin
  • Color - color is uneven; shades of black, brown and tan may be present and areas of white, grey, red, pink or blue may be seen
  • Diameter - there is a change in size, usually an increase; melanomas are usually larger than an eraser of a pencil (1/4 inch or 5 millimeters)
  • Evolution - another very important warning of melanoma is that a mole has been growing or changing its shape or color.

Some melanomas do not fit the ABCDE rule described above, so it is important to report changes in skin lesions, new skin lesions, any growths that look different from the rest of your moles, and sores that don't heal.

Melanomas can vary greatly in how they look. Many show all of the ABCDE features. However, some may show changes or abnormalities in only one or two of the ABCDE features. Melanomas may be found when an existing mole or new skin spot changes slightly in color or texture. More advanced tumors may itch, ooze, or bleed. However, melanoma usually does not cause pain.

Melanoma can be cured if it is diagnosed and treated when the tumor is thin and has not deeply invaded the skin. However, if a melanoma is not removed at its early stages, cancer cells may grow downward from the skin surface and invade healthy tissue. When a melanoma becomes thick and deep, the disease often spreads to other parts of the body and may be more difficult to control. Nevertheless, new and advanced treatments are developing for even the most aggressive melanomas. The Melanoma Program at the Center for Cancer Prevention and Diagnosis is at the forefront of these therapies.

People who have had melanoma have a high risk of developing a new melanoma. People at risk for any reason should check their skin regularly and have regular skin exams by a health care provider.

Know the ABCDEs of Melanoma Detection

The Melanoma Program medical experts recommend that you examine your skin monthly for signs of cancerous moles. If you notice any of the following warning signs, see your doctor, or call the Melanoma Program at 1-800-973-MOLE to speak to our dedicated melanoma navigator.

Benign Malignant Information

A symmetrical shape. Benign (harmless) moles are usually round and symmetrical. Melanomas are asymmetrical with two sides that are uneven or don't match.

Irregular Border. Melanomas have irregular, notched or scalloped borders.

Mixed Color. Benign moles are usually evenly brown or tan. Melanomas are often multi-colored with brown, black, red, white, or blue mixed together.

Large Diameter. Melanomas are usually 1/4 inch in diameter (about the size of a pencil eraser) or larger.

E is for evolution. Melanomas may change in appearance over time and may also become irritated (look for itching or bleeding).

Be aware that not all moles with these characteristics are melanomas. Likewise, some melanomas do not have any of these characteristics, and may be pink or white or not have any brown color at all. The most important warning sign for a melanoma is a change in the size, shape or color of a spot on your skin, or a new spot.


If your doctor suspects that a spot on the skin is melanoma, you will need to have a biopsy to make a definitive diagnosis. In this procedure, the doctor will anesthetize the skin and remove the suspicious growth. This can usually be done in an office setting under local anesthesia.