Moles - Diagnosis 

It is important to check your moles regularly and be aware of any changes in their colour, shape or size. Most changes are harmless and are due to a benign (non-cancerous) increase of pigment cells in the skin. However, visit your GP if a mole appears unusual.

See Moles - prevention for information about checking your moles and the changes to look out for.

Visiting your GP

Your GP will ask you about recent changes that have occurred to the mole and when the changes started. They may also ask you about your family history to find out how likely you are to be at risk of developing melanoma (a type of skin cancer).

Diagnostic checklist

Your GP will assess your mole using a checklist that consists of seven points from the National Institute for Health and Clinical Excellence (NICE). These are:

• whether the mole has changed size
• whether the mole is an irregular shape
• whether the mole is an irregular colour
• whether the mole measures 7mm (0.28 inches) or more across 
• whether the mole is inflamed (red and swollen) 
• whether the mole is oozing (leaking fluid)
• whether the mole has changed in sensation, for example, causing itching or pain

If there are only mild changes, your GP will probably take a clinical photograph of the mole and may measure it with a ruler. You may be asked to return in around eight weeks. Your GP will then compare your mole with the photograph and the measurements they took at your last visit to determine whether there have been any further changes.

If your mole shows signs of turning malignant (cancerous), your GP may refer you to a specialist under the two-week rule, so you should not wait more than 14 days to be seen. This might be with a:

• dermatologist (a specialist in conditions that affect the skin)
• plastic surgeon

Seeing a specialist

The specialist will examine you and either reassure you that the mole is not cancerous or they will cut the mole out. This is known as an excision biopsy. The entire mole should always be removed in one go unless it is large or in a difficult location.

NICE do not recommend that GPs perform biopsies on suspicious looking moles.

If the specialist decides to remove your mole, the sample will be sent to a laboratory to be looked at under a microscope for signs of cell changes.

If the mole is a suspected melanoma, your specialist will discuss this with you. Further tests may be necessary to check that the cancer has not spread. A multidisciplinary team (MDT) will probably take over your treatment. An MDT is a team of healthcare professionals with expertise in a variety of areas who work together to treat cancer. It may include:

• dermatologists
• plastic surgeons
• oncologists (specialists in cancer)
• pathologists (specialists in diagnosing diseases)
• skin cancer nurse specialists

See the Health A-Z topic about Skin cancer (malignant melanoma) - treatment for more information.