The first step in diagnosing a melanoma is a close examination of the spot. If the spot looks suspicious, the doctor will remove it so it can be checked in a laboratory. In some cases, further tests will be arranged.
Learn more about:
- Physical examination
- Removing the spot (excision biopsy)
- Checking the lymph nodes
- Understanding the pathology report
- Further tests
Physical examination
If you notice any changed or suspicious spots, see your GP. Your doctor will look carefully at your skin and ask if you or your family have a history of melanoma.
The doctor will consider the signs known as the ABCD and EFG guidelines and examine the spot more closely using a method called dermoscopy – this involves using a handheld magnifying instrument called a dermatoscope.
People with a high risk of developing melanoma and those with multiple moles may have photos taken of all their skin to make it easier to look for changes over time. This is known as total body photography. Not everyone needs total body photography.
Removing the spot (excision biopsy)
If the doctor suspects that a spot on your skin may be melanoma, the whole spot is removed (excision biopsy). While this is the preferred type of biopsy to remove the spot, other types of biopsy may be used.
How it happens
An excision biopsy is usually a simple procedure done in your doctor’s office. Your GP may do this procedure, or you may be referred to a dermatologist or surgeon.
For the procedure, you will have an injection of local anaesthetic into the area around the spot to numb the site.
The doctor will use a scalpel to remove the spot and a small amount of healthy tissue (2 mm margin) around it. It is recommended that the entire spot is removed rather than a small sample. This helps ensure an accurate diagnosis of any melanoma found.
The wound will usually be closed with stitches and covered with a dressing. You’ll be told how to look after the wound and dressing.
After the biopsy
A doctor called a pathologist will examine the tissue under a microscope to work out if it contains melanoma cells.
Getting the results
Results are usually ready within a week. Learn more about how to understand the pathology results.
You will have a follow-up appointment to check the wound and remove the stitches. If a diagnosis of melanoma is confirmed, you will probably need a second operation to remove more tissue. This is called a wide local excision.
Learn more about biopsies.
Checking lymph nodes
Lymph nodes are part of your body’s lymphatic system. This is a network of vessels, tissues and organs that helps to protect the body against disease and infection. Sometimes melanoma can travel through the lymphatic system to other parts of the body.
To work out if the melanoma has spread, your doctor may suggest tests to check the lymph nodes. Not everyone needs these tests.
Ultrasound
A scan used if lymph nodes feel enlarged. Learn more about ultrasounds.
Needle biopsy
If lymph nodes feel enlarged or look abnormal on ultrasound, you will probably have a fine needle biopsy. This uses a thin needle to take a sample of cells from the enlarged lymph node.
Sometimes, a thicker sample needs to be removed (core biopsy). The sample is examined under a microscope to see if it contains cancer cells.
If cancer is found in the lymph nodes, you may be offered a combination of surgery to remove the lymph nodes (lymph node dissection) and drug therapy (see immunotherapy and targeted therapy). This may be performed at a specialist melanoma unit.
Sentinel lymph node biopsy
When melanoma spreads, often the sentinel nodes are the first place it spreads to. A sentinel lymph node biopsy removes them so they can be checked for melanoma cells.
You may be offered a sentinel lymph node biopsy if you have no lymph nodes that feel enlarged and the melanoma is more than 1 mm thick (Breslow thickness) or is less than 1 mm with high-risk features. A sentinel node biopsy helps find melanoma in the lymph nodes before they become swollen. If your doctor thinks you need a sentinel node biopsy, you will have it at the same time as the wide local excision.
To find the sentinel lymph node, a small amount of radioactive dye is injected into the area where the initial melanoma was found. During the surgery, blue dye is also injected – any lymph nodes that take up both dyes will be removed so a pathologist can check them under the microscope for cancer cells.
If cancer cells are found in a removed lymph node, you may have further tests such as CT or PET–CT scans. The results of this biopsy can help predict the risk of melanoma spreading to other parts of the body. This information helps the multidisciplinary team plan your treatment options and decide whether to recommend drug therapies such as targeted therapy or immunotherapy.
Understanding the pathology report
The report from the pathologist is a summary of information about the melanoma that helps determine the diagnosis, the stage, the recommended treatment and the expected outcome (prognosis). You can ask your doctor for a copy of the pathology report.
It may include:
| Breslow thickness |
This is a measure of the thickness of the tumour in millimetres to its deepest point in the skin. The thicker a melanoma, the higher the risk it could return (recur) or spread to other parts of the body. Melanomas are classified as:
|
| Ulceration | The breakdown or loss of the outer layer of skin over the tumour is known as ulceration. It is a sign the tumour is growing quickly. |
| Mitotic rate | Mitosis is the process by which one cell divides into 2. The pathologist counts the number of actively dividing cells within a square millimetre to calculate how quickly the melanoma cells are dividing. |
| Clark level | This describes how many layers of skin the tumour has grown through. It is rated on a scale of 1–5, with 1 the shallowest and 5 the deepest. The Clark level is less accurate and not used as often now. |
| Margin | This is the area of normal skin around the melanoma. The report will describe how wide the margin is and whether any melanoma cells were found at the edge of the removed tissue. |
| Regression | This refers to inflammation or scar tissue in the melanoma, which suggests that some melanoma cells have been destroyed by the immune system. In the report, the presence of lymphocytes (immune cells) in the melanoma indicates inflammation. |
| Lymphovascular invasion | This means that melanoma cells have entered the lymphatic system or blood vessels. |
| Satellites | These are small areas of melanoma found separate from, but less than 2 cm away from, the primary melanoma. |
| Perineural invasion | This is when melanoma cells are found in and around the nerves of the skin. |
→ READ MORE: Further tests for melanoma
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A/Prof Rachel Roberts-Thomson, Medical Oncologist, The Queen Elizabeth Hospital, SA; A/Prof Robyn Saw, Surgical Oncologist, Melanoma Institute Australia, Royal Prince Alfred Hospital and The University of Sydney, NSW; Alison Button-Sloan, Consumer; Dr Marcus Cheng, Radiation Oncologist Registrar, Alfred Health, VIC; Prof Anne Cust, Deputy Director, The Daffodil Centre, The University of Sydney and Cancer Council NSW, Chair, National Skin Cancer Committee, Cancer Council, and faculty member, Melanoma Institute Australia; Prof David Gyorki, Surgical Oncologist, Peter MacCallum Cancer Centre, VIC; Dr Rhonda Harvey, Mohs Surgeon, Dermatologist, Green Square Dermatology, The Skin Hospital, Darlinghurst and Sydney Melanoma Diagnostic Centre, RPA, NSW; David Hoffman, Consumer; A/Prof Jeremy Hudson, Southern Cross University, James Cook University, Chair of Dermatology RACGP, Clinical Director, North Queensland Skin Cancer, QLD; Dr Damien Kee, Medical Oncologist, Austin Health and Peter MacCallum Cancer Centre and Clinical Research Fellow, Walter & Eliza Hall Institute, VIC; Angelica Miller, Melanoma Community Support Nurse, Melanoma Institute Australia, WA; Romy Pham, 13 11 20 Consultant, QLD; A/Prof Sasha Senthi, Radiation Oncologist, Alfred Health, and Clinical Research Fellow, Victorian Cancer Agency, VIC; Dr Chistoph Sinz, Dermatologist, Melanoma Institute Australia, NSW; Dr Amelia Smit, Research Fellow, Melanoma and Skin Cancer, The Daffodil Centre, The University of Sydney and Cancer Council NSW; Nicole Taylor, Clinical Nurse Consultant, Crown Princess Mary Cancer Centre, Westmead Hospital, NSW.
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