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Diagnosis
and Staging of Melanoma
How is melanoma diagnosed?
Medical examinations and tests are used to determine if a suspicious area is melanoma skin
cancer. In addition to a complete medical history, including family history, questions are
asked about the marking on the skin, such as when you first noticed it, as well as if and
how it has changed in size or appearance.
The suspected area, as well as the rest of your body is examined, noting the size,
shape, color, texture, and if there is bleeding or scaling. A skin sample will probably be
examined by a biopsy. The biopsy procedure chosen depends on the site and size of the
affected area.
Types of biopsies:
- skin biopsy - removes a sample of skin for examination under the microscope to
determine if melanoma is present. The biopsy is performed under local anesthesia, and you
will feel a small needle stick and a little burning for about a minute, with a little
pressure, but no pain.
- shave biopsy
- a type of skin biopsy in which the top layers of skin (the epidermis
and the most superficial part of the dermis) are shaved off. It is also performed
with a local anesthetic.
- punch biopsy
- removes a deeper sample of skin with a biopsy instrument that removes
a short cylinder or "applecore" of tissue. After a local anesthetic, the
instrument is rotated on the surface of the skin until it cuts through all the layers
including the dermis, epidermis, and the most superficial parts of the subcutis (the fat).
- excisional or incisional biopsy - used when a wider or deeper portion
of the skin is needed. Using a scalpel (surgical knife), a full thickness of
skin is removed for further examination, and the wound is sutured (with surgical thread).
When the entire tumor is removed, it is called excisional biopsy technique. If only a
portion of the tumor is removed, it is called incisional biopsy technique. Excisional
biopsy is the method usually preferred when melanoma is suspected.
- fine needle aspiration (FNA) biopsy - uses a thin needle to remove very
small tissue fragments from a tumor. Local anesthetic is sometimes used to numb the area,
but the test rarely causes much discomfort and leaves no scar.
FNA is not used for diagnosis of a suspicious mole, but may be used to biopsy large lymph
nodes near a melanoma to see if the melanoma has metastasized (spread). A computed tomography scan
(CT or CAT scan) -- an x-ray procedure that produces cross-sectional images of the body --
may be used to guide a needle into a tumor in an internal organ such as the lung or liver.
What is staging?
When melanoma is found, more tests will be done to find out
if the cancer cells have spread to other parts of the body. This is called staging,
and is necessary before treatment for the cancer can begin.
What are the stages for melanoma?
The National Cancer Institute stages of melanoma are:
- State 0 - Abnormal cells are found only in the outer
layer of skin and have not invaded deeper tissue.
- Stage I - Cancer is found in the outer layer of the skin
(epidermis) and/or the upper part of the inner layer of skin (dermis), but it has not
spread to nearby lymph nodes. The tumor is less than 1.5 millimeters (1/16 of an inch)
thick.
- Stage II - The tumor is 1.5 millimeters to 4 millimeters
(less than 1/6 of an inch) thick. It has spread to the lower part of the inner layer of
skin (dermis), but not into the tissue below the skin or into nearby lymph nodes.
- Stage III - any of the following may be evident:
- The tumor is more than 4 millimeters (approximately 1/6 of an inch)
thick.
- The tumor has spread to the body tissue below the skin.
- There are additional tumor growths within one inch of the original tumor
(satellite tumors).
- The tumor has spread to nearby lymph nodes or there are additional tumor
growths (satellite tumors) between the original tumor and the lymph nodes in the area.
- Stage IV - The tumor has spread to other organs, or to
lymph nodes, far away from the original tumor.
- Recurrent - recurrent disease means that the cancer has
come back (recurred) after it has been treated. It may come back in the original site or
in another part of the body.
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