What is melanoma?

Melanoma (also called malignant melanoma) is a cancer that usually starts in the skin. It can start in a mole or in normal-looking skin.

Melanoma develops from cells called melanocytes that start to grow and divide more quickly than usual. It's important to find and treat melanoma as early as possible. Melanomas that are only in the upper layer of skin are unlikely to spread into the blood or lymphatic vessels. They are usually cured with surgery.

There are four main types of skin melanoma:

  • Superficial spreading melanoma
  • Nodular melanoma
  • Lentigo maligna melanoma
  • Acral lentiginous melanoma.

The diagnosis and treatment for all four types are similar.

If melanoma is not removed the cells can grow deeper into the layers of the skin. If melanoma cells get into the blood or lymphatic system, they can travel to other parts of the body. We also have more information about:

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Symptoms of melanoma

About half of all melanomas start with a new, abnormal-looking mole in normal-looking skin. This usually looks like a dark area or a new mole that changes over weeks or months. Other melanomas develop from a mole that you already have.

It can be difficult to tell the difference between melanoma and a normal mole. We have more information about the signs and symptoms of melanoma.

Causes of melanoma

The main risk factor for developing melanoma is exposure to UV radiation. This can be through natural sunlight or the artificial light used in sunbeds or sunlamps.

Increasing age is also one of the main risk factors for melanoma. More than a quarter of melanomas are diagnosed in people aged over 75. We have more information about the risk factors for melanoma.

Tests and diagnosis for melanoma

If you have symptoms, you usually begin by seeing your GP. Your GP will check your mole and ask about any family history of cancer. If they think you may have a melanoma, they will refer you to a doctor who specialises in skin conditions.

You should be seen at the hospital within 2 weeks.

At the hospital

The specialist doctor will use a dermatoscope, which looks like a small magnifying glass, to look at your mole. They will also check the rest of your skin and ask about any other changes. The doctor may take photographs of any other unusual moles to check for changes over time.

If you have symptoms of melanoma, your mole will need to be removed so the specialist doctor can find out what it is. This is called an excision biopsy.

If it is not clear that your mole is melanoma, your specialist will ask you to come back in a few months to check if the mole has changed.

The specialist will usually also check the lymph nodes closest to the mole. This is to see if they look or feel swollen.

Tests to check your lymph nodes

If you are diagnosed with melanoma, your doctor may suggest some tests to check the lymph nodes. Not everyone needs these test. Whether you have them depends on the size of the melanoma and if the lymph nodes look or feel swollen. These tests include:

  • A sentinel lymph node biopsy (SLNB)

    A sentinel lymph node biopsy is a way of checking the lymph nodes closest to the melanoma

  • Ultrasound

    An ultrasound scan uses sound waves to make up a picture of an area of the body.

  • Fine needle aspiration (FNA)

    If the ultrasound scan of the lymph nodes is abnormal, the doctor will do a fine needle aspiration.

Further tests

If the melanoma has spread to the lymph nodes, you may have the following tests to check if melanoma has spread anywhere else in the body:

  • CT scan

    A CT scan takes a series of x-rays, which build-up a three-dimensional picture of the inside of the body.

  • MRI scan

    An MRI scan uses magnetism to build up a detailed picture of areas of your body.

  • PET-CT scan

    A PET-CT scan is a combination of a CT scan and a PET scan. A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body.

  • Tests on the melanoma cells

    If the melanoma has spread to the lymph nodes, your doctor may test the melanoma cells for any change to the genes.

Waiting for tests results can be a difficult time, we have more information that can help.

Stages of melanoma

The results of your tests help your doctors find out more about the size and position of the melanoma and whether it has spread. This is called staging.

Treatment for melanoma

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your doctor or cancer specialist or nurse will explain the different treatments and their side effects. They will also talk to you about things to consider when making treatment decisions.

Surgery is the main treatment for melanoma. Most people diagnosed with melanoma will have surgery after their mole has been removed.

If all the melanoma cells are removed during your surgery, you will not need any more treatment.

Some people may have tests to check the lymph nodes. If the tests find melanoma cells in the lymph nodes, you may be offered further surgery to remove nearby lymph nodes.

We have more information about treatment for melanoma.

You may have some treatments as part of a clinical trial.

After melanoma treatment


After the melanoma is removed, you will see your cancer doctor again for a follow-up appointment. After you have a melanoma, you have a higher risk of getting another melanoma. So they will also give you advice on protecting your skin from the sun.

We have more information on follow-up care after treatment for melanoma and staying safe in the sun.

You may get anxious between appointments. This is natural. It may help to get support from family, friends or a support organisation.

Macmillan is also here to support you. If you would like to talk, you can:

Well-being and recovery

Even if you already have a healthy lifestyle, you may choose to make some positive lifestyle changes after treatment.

Making small changes such as eating well and keeping active can improve your health and wellbeing and help your body recover.

Reviewed: 31 July 2019
Reviewed: 31/07/2019
Next review: 31 July 2021
Next review: 31/07/2021

This content is currently being reviewed. New information will be coming soon.