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
If you notice any changed or suspicious spots, your doctor will look carefully at your skin. The doctor will 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 with dermoscopy, which involves using a handheld magnifying instrument called a dermatoscope.
People with a high risk of developing melanoma may have photos taken of their skin to make it easier to look for changes over time. This is known as total body photography.
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 may be used.
How it happens
An excision biopsy is generally 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 area. 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’ll 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.
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. There are large groups of lymph nodes in the neck, armpits and groin. Sometimes melanoma can travel through the lymphatic system to other parts of the body.
To work out if the melanoma has spread, your doctor will suggest tests to check the lymph nodes. Not everyone needs these tests.
Used if any lymph nodes feel enlarged.
Fine needle biopsy
If any lymph nodes look or feel enlarged, 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 surgery to remove them (lymph node dissection). This may be at a specialist melanoma unit.
You may be offered a sentinel lymph node biopsy if 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.
When melanoma spreads, it first travels to particular lymph nodes. These are called the sentinel nodes. A sentinel node biopsy finds and removes them so they can be checked for melanoma cells under a microscope. If your doctor thinks you need a sentinel node biopsy, you 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. The surgeon removes any lymph nodes that take up the dye 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 a sentinel lymph node 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 you are suitable for drug therapies.
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:
- in situ – found only in the top layer of the skin (epidermis)
- thin – less than 1 mm
- intermediate – 1–4 mm
- thick – greater than 4 mm.
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 two. 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. (On the report, the Clark level will be written in Roman numerals as I, II, III, IV or V.) The Clark level is not the same as the stage.
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 – Small areas of melanoma found more than 0.05 mm but less than 2 cm from e primary melanoma.
Podcast: Tests and Cancer
Prof H Peter Soyer, Chair in Dermatology and Director, Dermatology Research Centre, The University of Queensland, Diamantina Institute, and Consultant, Dermatology Department, Princess Alexandra Hospital, QLD; A/Prof Matteo Carlino, Medical Oncologist, Blacktown and Westmead Hospitals, Melanoma Institute Australia and The University of Sydney, NSW; 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 Diona Damian, Dermatologist, Head of Department, Dermatology, The University of Sydney at Royal Prince Alfred Hospital, NSW, and Melanoma Institute Australia; A/Prof Paul Fishburn, General Practitioner – Skin Cancer, Norwest Skin Cancer Clinic, NSW and The University of Queensland; Claire Kelly, National Support Manager, and Emma Zurawel, Telehealth Nurse, Melanoma Patients Australia; Prof John Kelly, Consultant Dermatologist, Victorian Melanoma Service, The Alfred Melbourne and Monash University, VIC; Liz King, Manager, Skin Cancer Prevention Unit, Cancer Council NSW; Lee-Ann Lovegrove, Consumer; Lynda McKinley, 13 11 20 Consultant, Cancer Council Queensland; Angelica Miller, Melanoma Community Support Nurse, Melanoma Institute Australia incorporating melanomaWA, and Cancer Wellness Centre, WA; Dr Amelia Smit, Research Fellow, Melanoma and Skin Cancer, The Daffodil Centre, The University of Sydney and Cancer Council NSW; Prof Andrew Spillane, Professor of Surgical Oncology, The University of Sydney, The Mater and Royal North Shore Hospitals, NSW, and Melanoma Institute Australia; Kylie Tilley, Consumer; A/Prof Tim Wang, Radiation Oncologist, Crown Princess Mary Cancer Centre, Westmead Hospital, NSW. We also thank the health professionals, consumers and editorial teams who have worked on previous editions of this title.
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