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Biopsy and Diagnosis

Often, the first sign of melanoma is a change in the size, shape, color, or feel of an existing mole. Most melanomas have a black or blue-black area. Melanoma also may appear as a new mole. 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 ABCD 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 ABCD features. However, some may show changes or abnormalities in only one or two of the ABCD features.

Melanomas in an early stage may be found when an existing mole changes slightly, for example, when a new black area forms. Newly formed fine scales and itching in a mole also are common symptoms of early melanoma. In more advanced melanoma, the texture of the mole may change. For example, it may become hard or lumpy. Melanomas may feel different from regular moles. More advanced tumors may itch, ooze or bleed. But melanomas usually do 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 is difficult to control.

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.


If your doctor suspects that a spot on the skin is melanoma, you will need to have a biopsy. A biopsy is the only way to make a definite diagnosis. In this procedure, the doctor tries to remove all of the suspicious-looking growth. This is an excisional biopsy. If the growth is too large to be removed entirely, the doctor removes a sample of the tissue. The doctor should not “shave off” or cauterize a growth that might be melanoma. A shave biopsy is useful for many types of skin diseases and in treating benign moles. But it is not often used if a melanoma is suspected. This is because the sample removed may not be thick enough to find out how deep the cancer goes into the tissues.

A biopsy can usually be done in the doctor’s office using local anesthesia. A pathologist then examines the tissue under a microscope to check for cancer cells. Sometimes it is helpful for more than one pathologist to check the tissue for cancer cells.