How Is Melanoma Diagnosed?

Diagnosis of any medical condition begins with a medical history and physical exam. These procedures form the “framework” of your overall health. From this general information, your doctor will begin to fill in the details, focusing on the symptoms that have brought you to seek medical care.

You will be asked about your risk factors for skin cancer, such as sun exposure and whether you have had any type of skin cancer in the past; what symptoms you have noticed; and any other health problems or concerns. In addition to the medical history, a physical exam will be performed. This typically includes measuring blood pressure and temperature. Any suspicious areas or patches of skin will be closely examined. Areas of your body that are not usually visible, such as the inside of your mouth and between your toes and fingers, will be examined for suspicious-looking lesions.

Biopsy

To determine whether a suspicious mole is cancerous, your doctor will perform a biopsy. In this procedure, tissue is collected and examined under a microscope to look for cancer cells.

Excisional Biopsy

The type of biopsy that will be done to diagnose melanoma is called an excisional biopsy. In this procedure, a scalpel is used to remove the entire abnormal growth. This is usually a minor procedure that can be done in the doctor’s office.

Sentinel Node Biopsy

In rare cases, melanoma may have spread to other locations in the body, such as the lymph nodes or lungs. When this happens, the original skin melanoma may still be small. Melanoma that has metastasized (spread) to other parts of the body may not be found until long after the original skin melanoma has been removed. A biopsy can be performed to confirm the type of cancer that has arisen in these other locations.

If the initial biopsy indicates that melanoma is present, additional tests can be performed to determine whether the cancer has spread elsewhere in the body. The first step is likely to be a sentinel node biopsy.

The lymph system helps drain fluid and waste from the body, and lymph nodes are like tiny way stations that filter out impurities and help fight infection. In a sentinel node biopsy, the lymph node that is nearest to the site of the melanoma is tested to determine whether the cancer cells have made their way into regional (nearby) lymph nodes. (Since the lymph system carries fluid throughout the body, this is the primary way in which cancer spreads.)

To identify which is the sentinel node (the lymph node that is the first “way station” to drain fluid from the site of the tumor), a special dye is injected into an area near the tumor and traced to the nearest lymph nodes. The sentinel node is then removed and dissected to look for the presence of cancer cells. In some cases, one or two additional regional nodes are removed along with the sentinel node.