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Diagnosis of Melanoma
You will be asked about your symptoms, and medical and family history. A complete physical exam will be done. Your skin will be thoroughly examined. A dermatoscope is used to magnify skin lesions so they are easier to evaluate. Your doctor may suspect melanoma based on the skin exam. Many cases of melanoma are found during a physical exam or during a self-exam of your skin at home.
Diagnosis of Melanoma
Melanoma is confirmed with a skin biopsy. A sample of the suspicious tissue will be taken and examined under a microscope for the presence of cancer cells. A local anesthetic is used before taking the sample to eliminate pain during the procedure.
Types of skin biopsies:
- Shave—The mole is shaved off in layers from the top to the bottom. This is more useful when sampling several moles. Shaving does not get enough depth to get under or around the affected mole.
- Punch—A circular device is used to cut out the suspicious tissue. The deeper cut allows the doctor to get through all the skin layers. If needed, the remaining edges of skin can stitched and bandaged.
- Incisional—Only a part of the affected area is removed. Since more skin needs to be taken, it may be cut out in a slice or wedge. Stitches are used to close the remaining skin together.
- Excisional—The entire area with a margin of healthy tissue is removed. Like an incisional biopsy, a larger piece of the skin is taken. Stitches are used to close the remaining skin together.
Lymph Node Biopsy
If melanoma has spread down into the dermis it may spread to nearby lymph nodes. A lymph node biopsy involves removing lymph tissue for examination under a microscope. If cancer cells are found, it indicates that melanoma has spread beyond the mole.
Types of lymph node biopsies:
- Fine needle aspiration—A thin needle is used to remove fluid and/or cells from a lymph node.
- Surgical excision—The entire lymph node is removed.
Staging of Melanoma
If melanoma is confirmed, results from completed tests and new tests will help determine the stage of cancer. Staging is used to determine characteristics of the tumor that will help develop the prognosis and treatment plan. Factors that play a role in staging include how far the original tumor has spread, whether lymph nodes are involved, and microscopic cellular details.
Tests that may help determine melanoma stage:
- Blood tests to look for abnormal numbers of certain blood cells, proteins, indications of cancer, and abnormal cells. The tests may also show changes in kidney or liver function. For example, high blood levels of lactate dehydrogenase (LDH) may make advanced melanoma more resistant to treatment.
- Imaging tests—To help determine the depth of melanoma invasion. They will also help determine if other structures are involved and evaluate other parts of the body for metastatic growths. Some tests use contrast material to highlight structure so images are more clear and detailed. Imaging tests may include:
- Sentinel lymph node biopsy—Sentinel lymph nodes are the first nodes that a tumor will drain into. These nodes are located by injecting a traceable material near the tumor and watching which nodes take up the material first. If these nodes are free of cancer cells, it is unlikely that the cancer has spread. If cancer cells are present, then more lymph nodes may need to be removed to determine how far the cancer has spread.
- Tissue evaluation—Cancer tissue from the biopsy will be closely examined to look for characteristics that can help with prognosis and treatment selection. Important characteristics include the presence of genetic mutations like BRAF. BRAF mutations allow certain medications to work better in the treatment of advanced melanoma.
Stages of Melanoma
Melanoma is staged from 0-IV:
- Stage 0—Melanoma in situ—A very localized group of abnormal cells are still contained in the primary site. The cancer remains in the epidermis and has not spread.
- Stage IA—The tumor is 1 millimeter (mm) or less in thickness WITHOUT an ulcer.
- The tumor is 1 mm or less in thickness WITH an ulcer OR
- The tumor is 1-2 mm thick WITHOUT an ulcer
- The tumor is 1-2 mm thick WITH an ulcer OR
- The tumor is more than 2-4 mm thick WITHOUT an ulcer
- The tumor is 2-4 mm thick WITH an ulcer OR
- The tumor is over 4 mm thick WITHOUT an ulcer
- Stage IIC—The tumor is over 4 mm thick WITH an ulcer
Stage IIIA—The tumor can be any thickness WITH or WITHOUT an ulcer AND one or more conditions:
- Cancer is found in one or more lymph nodes
- Lymph nodes are joined together
- Cancer is found in a lymph vessel that runs from the tumor to nearby nodes—cancer that is found is over 2 centimeters (cm) from the main tumor
- Smaller tumors are on or under the skin and up to 2 cm from the main tumor
- Stage IV—Melanoma has spread beyond the main tumor to other parts of the body. The most common sites for metastatic melanoma are the lungs, liver, brain, bones, and intestinal tract.
General information about melanoma. National Cancer Institute website. Available at: https://www.cancer.gov/types/skin/patient/melanoma-treatment-pdq. Updated March 10, 2017. Accessed March 16, 2017.
Melanoma. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115302/Melanoma. Updated January 10, 2017. Accessed March 16, 2017.
Melanoma skin cancer changes. American Cancer Society website. Available at: https://www.cancer.org/cancer/melanoma-skin-cancer/detection-diagnosis-staging/melanoma-skin-cancer-stages.html. Updated May 20, 2016. Accessed March 16, 2017.
Stages of melanoma. National Cancer Institute website. Available at:https://www.cancer.gov/types/skin/patient/melanoma-treatment-pdq#section/%5F96. Updated March 10, 2017. Accessed March 16, 2017.
Tests for melanoma skin cancer. American Cancer Society website. Available at: https://www.cancer.org/cancer/melanoma-skin-cancer/detection-diagnosis-staging/how-diagnosed.html. Updated May 20, 2016. Accessed March 16, 2017.
- Reviewer: Mohei Abouzied, MD, FACP
- Review Date: 03/2017
- Update Date: 10/18/2016