Diagnosis and Staging of Melanoma
How is melanoma diagnosed?
Medical examination, dermoscopy, and skin biopsy are typically used to determine if a suspicious area on the skin is melanoma. 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 is usually examined microscopically following the performance of a skin biopsy. The biopsy procedure chosen depends on the site and size of the affected area. Most skin biopsies are performed by dermatologists, who specialize in cutaneous malignancies and other skin conditions.
Types of biopsies:
Skin biopsySkin biopsies involve removing a sample of skin for examination under the microscope to determine if melanoma is present. The biopsy is performed under local anesthesia. The patient usually just feels a small needle stick and slight burning for about one minute, with a little pressure, but no pain.
The different types of biopsies include the following:
- Punch biopsy
Punch biopsies involve taking a sample of skin with a biopsy instrument that removes a short cylinder, or "apple core," of tissue. After a local anesthetic is administered, 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 (fat).
- Shave biopsy
This type of biopsy involves removing the top or deeper layers of skin by shaving it off. Shave biopsies are also performed with a local anesthetic. Superficial shave biopsies are discouraged if cutaneous melanoma is suspected.
- Fusiform/scalpel biopsy (generally excisional)
This type of biopsy is done with the intent to remove the whole lesion and involved placement of superficial and deep sutures. Punch and shave biopsies may also be excisional in nature.
Skin biopsies may be partial (incisional) or complete (excisional) in intent.
- Incisional (partial) biopsy
This type of biopsy is often used when a wider or deeper portion of the skin is needed. Using a punch biopsy tool or scalpel (surgical knife), a full thickness of skin is removed for further examination, and the wound is either sutured (with surgical thread) or left open to heal (shave biopsy).
- Excisional biopsy
An excisional biopsy is performed with the intent to remove the entire tumor for histopathologic (microscopic) examinatinon. Excisional biopsy is the preferred method when melanoma is suspected. Excisional biopsies may be performed via punch biopsy of a suspicious skin lesion, deep (or saucerization) shave biopsy, or with a fusiform excision (scalpel excision closed with sutures).
Biopsy of enlarged lymph nodes or lumps in the skin may be performed with fine needle aspiration.
- Fine needle aspiration (FNA) biopsy
This type of biopsy involves using a thin needle to remove very small pieces 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). Ultrasound or 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 American Joint Committee on Cancer 2002 stages of melanoma are:
| Stage 0 | Melanoma cells are found only in the outer layer of skin (epidermis) and have not invaded deeper tissue. Also called "in situ" or "intraepithelial melanoma". |
|---|---|
| Stage I | Cancer is found in the outer layer of the skin (epidermis) and/or the upper part of the inner layer of skin (papillary dermis), but it has not spread to nearby lymph nodes. The tumor is less than 2 mm thick. Stage I cutaneous melanoma is further divided into stage IA and stage IB depending on tumor depth and other histologic features. |
| Stage II | The tumor is thicker than 2 millimeters. It has spread to the lower part of the of the skin (reticular dermis and/or subcutaneous fat), but not into into nearby lymph nodes. Stage II cutaneous melanoma is further divided into stage IIA, IIB and IIC depending on tumor depth and other histologic features. |
| Stage III | The tumor has spread to regional lymph nodes located in the nearest lymph node basin to the primary skin tumor. |
| Stage IV | The tumor has spread to other organs (liver, lungs, brain, gastrointestinal tract, bone), or to distant skin, subcutaneous or lymph node sites or far away from the original skin tumor. |
Always consult your physician for more information regarding the staging of melanoma.
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