Melanoma Diagnosis

Skin Biopsy

Most melanomas are diagnosed using a skin biopsy. The main types of skin biopsies are:

• Fine Needle Aspirate (FNA): technique in which a needle is inserted into the tissue or tumor to aspirate (take out) fluid and cells. This tissue/fluid is smeared onto a slide and is then looked at under a microscope. FNA can be performed in the office or under radiology guidance.
• Shave Biopsy: technique in which a portion of a lesion is cut off the surface of the skin using a scalpel in most cases. This is often performed by a dermatologist in the office.
• Punch Biopsy: technique in which a lesion is removed from the skin using a cookie cutter type device. This is used to remove small lesions or to sample a portion of a larger lesion.
• Incisional Biopsy: technique in which a lesion is removed from the skin by cutting out the affected area. This technique is often used to remove larger lesions.
• Excisional Biopsy: technique in which a lesion is removed from the skin by cutting out the affected area as well as a portion of normal skin surrounding the lesion. This technique is also used to remove larger lesions.  This technique is generally the best way to to remove a suspicious lesion because they are designed to remove the entire lesion.

Understanding Your Melanoma Diagnosis

Have you been diagnosed with melanoma? If so, you may want to read the Just Diagnosed with Melanoma...Now What? booklet.

First Step in Melanoma Diagnosis - Tissue Analysis

For a melanoma diagnosis, tissue is removed from the skin to be examined under a microscope by a person specialized in analyzing skin specimens. This is often a dermatopathologist who is specially trained in melanoma biopsies. After analyzing the tissue, the pathologist will issue a pathology report—if the lesion is determined to be a melanoma, all specific information important in determining prognosis and melanoma recurrence risk will be included.  

The depth in millimeters and the presence or absence of ulceration provides the most important information related to prognosis at this time. Mitotic rate is also very important in determining a person’s prognosis. Following this initial biopsy, a wider local excision is often performed to ensure that the entire lesion was removed along with a clear margin of normal tissue around the melanoma.

Second Step in Melanoma Diagnosis - Lymph Node Status

A second step in the diagnosis of melanoma and to determine a person’s stage of melanoma is analyzing the lymph node status. When the original or primary melanoma has certain high risk characteristics, the lymph nodes are examined to determine if there is additional involvement. These characteristics include a depth greater than 1 mm, a Clark’s Level greater than IV, the presence of ulceration and sometimes regression. If the primary melanoma meets these characteristics, a sentinel lymph node biopsy is often performed.

During a sentinel lymph node biopsy, a radioactive tracer and a dye are injected into the site of the primary melanoma. These agents are then traced to the “draining” lymph node basin. A small incision is made into the area where these two agents traveled and the lymph nodes involved are removed. They are then examined under a microscope to determine if there are any melanoma cells detected.

• If no melanoma cells are found, then no further surgical intervention is performed.
• If this lymph node does contain melanoma cells, then a second surgery to remove additional lymph nodes will be performed. These additional lymph nodes are also evaluated by a pathologist to determine if they contain any melanoma cells.

This information is important in determining the stage of the melanoma.