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Diagnosis Cancer


If your doctor suspects that a spot on the skin is melanoma, you will need a biopsy, which is the only way to make a definite diagnosis. In this procedure, your doctor tries to remove all of the suspicious-looking growth. If the growth is too large to be removed entirely, your doctor may remove a sample of the tissue.

A biopsy usually can be done in the doctor's office using a local anesthetic. A pathologist then examines the tissue under a microscope to check for cancer cells.

Often, the pathologist can easily tell whether these cells represent melanoma or a non-cancerous mole. Sometimes, however, the distinction can be tricky, and special stains or further diagnostic tests must be performed to make the diagnosis. Distinguishing between cancerous and non-cancerous tumors can make all the difference for a patient, as the treatment and outcomes can be very different.

A pathologist can identify many other characteristics of the melanoma to determine how likely the cancer can be successfully treated. If you've had a biopsy at another medical center, we will ask an experienced pathologist at UCSF to review them as well.

Melanoma Staging

  • Stage 0 These melanomas are confined to the top most layer of the skin, called the epidermis. In most cases, patients can be cured with surgery to remove the cancer. However, these patients should be monitored for the small risk of melanoma recurrence as well as the development of a second, unrelated skin melanoma.
  • Stage I Unlike stage 0 melanoma, these melanomas have invaded through the epidermis. They are considered to be the thinnest of the "invasive" melanomas. There is a small chance that some of these melanomas have spread microscopically to the lymph nodes. In cases with a substantial risk of lymph node involvement, a sentinel lymph node biopsy may be performed, usually at the same time as the surgical removal of the skin melanoma.
  • Stage II These are thicker melanomas that have invaded deeper into the skin. As a melanoma becomes deeper, there is a greater possibility that it can spread to other sites in the body. Sentinel lymph node biopsies may be performed when the skin melanoma is surgically removed. In cases where there is a high risk of melanoma developing elsewhere in the body, adjuvant treatment — treatment that attempts to lower the risk of melanoma recurrence — may be offered after the surgery.
  • Stage III These include melanomas that have spread to the local lymph nodes. These melanomas have a substantial risk of recurring, or manifesting in distant organs. Therefore adjuvant therapy — treatment that attempts to lower the risk of melanoma recurrence — is offered after the melanoma is surgically removed. Radiation treatment may be considered in certain patients.
  • Stage IV In this stage, the cancer has spread to distant organs. In general, patients are treated with systemic therapy, or therapy that targets the entire body. Radiation treatment may be recommended, as well as experimental treatments as part of a clinical trial or study. At the UCSF Melanoma Center, each patient's case is assessed individually to find the best treatment options.

Genetic Mutations in Melanoma

All melanomas are not alike. Scientists have discovered that melanomas tend to have specific mutations in their DNA, depending on where they originated.

The UCSF Melanoma Center has the ability to analyze cancer cells to test for specific mutations, including the genes known as BRAF, NRAS and KIT. A mutation in one of the genes may cause the melanoma to be more responsive to certain treatments. We offer mutation testing to patients who are identified as most likely to benefit from this service.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.