Diagnosis of Melanoma
You will be asked about your symptoms and medical history. A physical exam will be done. Many cases of melanoma are found during routine physical exams or when doing a skin self-exam.
Your skin and moles will be examined. If any of your moles look like they may be cancerous, a tissue sample will be taken and sent to a laboratory for testing. A pathologist will examine the tissue sample under a microscope to check for cancer cells. Other moles will be monitored over time.
The lymph nodes in the groin, underarm, neck, or areas near the suspicious mole may also be examined. Enlarged lymph nodes suggest that the melanoma
have spread beyond the mole. A sample of lymph node tissue may need to be removed to test for cancer cells.
It is important to know whether the melanoma has extended beyond the tumor site to involve lymph nodes as this changes both the stage of the tumor and the treatment required.
Once melanoma is found, tests are performed to find out the thickness of the primary lesion and whether the cancer has spread and, if so, to what extent. This information helps determine which treatment is best for you. Melanoma, like other cancers, is classified according to stages. The lower the stage, the more likely the tumor is to be cured and the easier it is to treat.
Staging is a careful attempt to determine the extent of the cancer invasion. It considers the thickness of the tumor, presence of cancer cells in local lymph nodes, whether the cancer has spread beyond its primary localization and, if it has, what body parts are affected. Depending on the thickness of the original tumor, additional tests to determine staging may include:
- Blood tests
- Chest x-rays
- PET scan
—A radioactive substance is injected into your bloodstream and tracked by a scanning machine. Cancerous areas absorb more of the radioactive substance than normal tissue and show up as hot spots in advanced stages of cancer.
- MRI scan
—Magnetic waves are used to take pictures inside the body. In some cases, you may have a contrast dye injected into your bloodstream.
- CT scan
—Similar to x-rays, it takes clearer pictures and multiple views inside the body. CT scans can image organs and blood vessels. In some cases, you may have a contrast dye injected into your bloodstream.
- Sentinel lymph node study—Here the surgeon injects a radioactive tracer into the tumor site and then follows the tracer into the lymph node region. They then selectively remove only those nodes that pick up the radioactivity to see if they have cancer in them. If they do, a more complete lymph node dissection is performed, as is chemotherapy and immunotherapy. If none of the lymph nodes have cancer in them, the procedure is completed and further therapies are usually not offered unless the tumor itself was quite deep or large.
The following stages are currently used to classify melanoma:
In stage 0, abnormal melanocytes are found in the epidermis, the outer layer of the skin. These abnormal melanocytes may become cancer and spread into nearby normal tissue. Stage 0 is also called melanoma in situ.
In stage I, melanoma has formed. Stage I is divided into stages IA and IB. In stages IA and IB, melanoma is not in found lymph nodes or distant organs.
- Stage IA: In stage IA, the tumor is not more than 1 millimeter thick, with no ulceration.
Stage IB: In stage IB, the tumor is either:
- Not more than 1 millimeter thick with ulceration.
- 1 to 2 millimeters thick with no ulceration.
Stage II is divided into stages IIA, IIB, and IIC. All stage II melanomas are not found in found lymph nodes or distant organs.
Stage IIA: In stage IIA, the tumor is either:
- 1 to 2 millimeters thick, with ulceration.
- 2 to 4 millimeters thick, with no ulceration.
Stage IIB: In stage IIB, the tumor is either:
- 2 to 4 millimeters thick, with ulceration.
- More than 4 millimeters thick, with no ulceration.
- Stage IIC: In stage IIC, the tumor is more than 4 millimeters thick, with ulceration.
Stage III: In stage III, the tumor may be any thickness and it has spread to regional lymph nodes without
In stage IV, the melanoma has spread to other places in the body, beyond the original area of the skin. This can include distant lymph nodes or organs.
Diagnosing melanoma. Melanoma Research Foundation website. Available at:
http://www.melanoma.org/learn-more/melanoma-101/imaging-tests. Accessed April 3, 2014.
Melanoma. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed. Updated March 19, 2014. Accessed April 3, 2014.
Melanoma skin cancer. American Cancer Society website. Available at:
http://www.cancer.org/acs/groups/cid/documents/webcontent/003120-pdf.pdf. Updated January 9, 2014. Accessed April 3, 2014.