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What is a mole?

A mole is a collection of pigment cells present within the skin. These cells are known as melanocytes. Sometimes moles are referred to their scientific term melanocytic naevi. They are extremely common. Most people are born with a few moles and develop others during their lives they vary in size from some barely visible to large moles covering virtually the entire body (termed bathing trunk naevi).

What causes moles?
Most moles are simply the result of a harmless overgrowth of the pigment producing cells within the skin. Most moles develop spontaneously or are caused by exposure to sunlight and tend to appear on those areas of the skin that catch the most sunlight – usually the trunk/arms and legs. However moles can appear anywhere on the body including the groin, soles of feet and under the nails of the toes and fingers

Most of these moles appear during the first 20 years of life, although they may continue to develop into the 30s and 40s. 

Why are moles a concern?
The main worry with moles is that a small number may go on to develop a form of skin cancer so called malignant melanoma. This form of skin cancer, which can be fatal, is best spotted early and treated with surgical excision (i.e. it is cut out of the skin). But bear in mind that melanoma - the cancerous form of a mole - can appear de novo - with no prior history of an existing mole.

Who is at risk?
The presence of moles should not cause you serious problems. But large numbers, more than 25, are an indication of susceptibility to melanoma. So you should take great care about exposure to sunlight.

If there is a family history of malignant melanoma, you should be particularly vigilant about changing moles.

What are the symptoms of malignancy (melanoma)?

The mole is itchy and painful – for no obvious reason and this persists

Increased size or an increasingly irregular appearance, especially at the edges.

A change in colour, particularly if the mole gets darker or becomes mottled.

Spontaneous bleeding.

Satellite pigmented lesions, i.e. new moles develop extend beyond the original mole

How is malignancy diagnosed?

Although most changes in the size, shape and colour of moles are due to a benign, non-cancerous increase in number of pigment cells, any mole that looks unusual should be examined. Your doctor will probably request information on recent changes to the mole along with a family history to assess your risk. It is a change in the size/shape or colour of the mole which can usually prompt a visit to your GP who will either offer reassurance or advocate an opinion from a dermatologist

If only mild changes are found, your doctor will usually only need to take a clinical photograph of it or measure it and ask you to keep an eye on it. The mole's appearance may be reviewed in a later appointment. But if your doctor is concerned then they may choose to refer you to a skin specialist (dermatologist) for assessment and possible removal.

The definitive way to confirm whether a mole is sinister or not is for a dermatologist to remove it and send it for analysis. This is usually done under local anaesthesia and the wound closed with stitches. The mole is then sent off and reported within 2 weeks  -  if the mole is found to be sinister then it needs to be discussed at a multidisciplinary meeting (MDT).


Dr Cliff is chair of the local skin MDT and represents the skin department at the specialist MDT which meets each Thursday virtually. All skin cancers are discussed at this meeting and the outcomes relayed back to the patient to ensure that the correct management is offered to the patient.

General Advice

·       Avoid unnecessary exposure to sunlight, particularly during the two hours on either side of midday when the sun’s rays are strongest, and avoid getting sunburn.

·       Keep covered up in sunlight and apply sunscreen on exposed skin.

·       Examine your moles regularly and get someone to check those you cannot see.

Other Types of Moles

Dysplastic Naevus Syndrome

Some large moles have an irregular outline and an indistinct border. These carry an increased risk of malignancy and tend to occur in families who have a history of malignant melanoma. Patients with such moles need to have them examined regularly and compared with clinical photographs.

We are able to offer mole screening for high risk individuals or those with a strong family history of skin cancer. This provides reassurance but allows the early diagnosis of potential skin cancer and their early management.

If there is a major worry regarding a lesion then an urgent appointment can be organised to see us either by calling our PA Sarah Edwards or requesting your GP to send an urgent fax or email to

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