A mole, otherwise known as a Naevus (plural Nevi), is a common benign skin lesion which is caused by the proliferation of pigment cells.
Most adults will have at least a few moles. These can be present from birth (congenital naevus), or appear later in life (acquired naevus).
Although moles are harmless, melanoma, a type of skin cancer, can grow near a moles. This is why it is important to get your mole(s) checked if you are concerned that it is displaying any of the characteristics of the ABCDEs of melanoma.
What causes Moles?
It is not known what causes the local proliferation of naevus cells, but the number of moles a person has depends on a number of factors including genetic predisposition, immune status, and sun exposure.
There has also been a link between drugs like BRAF inhibitor and immunosuppressive treatment leading to an increase in numbers of moles.
Who is at risk of Moles?
Although most adults have at least a few moles, there is a genetic link with people that have many moles.
People living in Australia and New Zealand tend to have many more moles than people living in Northern Europe. This could be linked to sun exposure.
Those with more than 4 atypical moles are at an increased risk of developing melanoma, especially if direct relatives (mother, father, sibling) have had one, so should regularly check the appearance of moles.
What are the symptoms of Moles?
Moles can differ greatly in appearance, size and number, depending on where they are, and the colour of your skin, but will usually have these common traits:
- Round or oval is shape
- One colour – this can be brown, black, tan, blue , red or pink
- Flat or slightly raised
- Retain the same appearance month to month
Moles can range from a few millimetres to a few centimetres, they can appear on any part of your body, and in varying numbers. Some moles also grow hair. None of these characteristics are any cause for concern.
However, you should be aware of the ABCDEs of melanoma. If moles display any of the following traits they could be signs of potential melanoma, a form of skin cancer.
- Asymmetry: One half doesn’t match the appearance of the other half.
- Border irregularity :Poorly defined borders
- Colour: The mole is more than one colour
- Diameter: Melanoma is usually more than 6mm diameter
- Evolution: Is the mole changing in size and does it look different from the rest?
There are exceptions to this including an ‘atypical’ or ‘dysplastic’ mole which has an odd shape, and shows more than one colour. Because of this it can look like melanoma. If you have any concerns you should contact a dermatologist.
Images of Moles
These images are kindly provided by DermNetNZ.org for non-commercial use, for the purpose of education and information. The images have not been modified and DermNetNZ do not endorse The London Skin and Hair Clinic. You can find a copy of the license at http://creativecommons.org/licenses/by-nc-nd/3.0/nz/.
How does a dermatologist diagnose Moles?
A Dermatologist is trained to diagnose moles and identify what is malignant and what is not malignant. They use a Dermatascope which is a magnification device to assess the features of the mole. Where the Dermatologist wants to monitor the mole they will use digital photography to record the mole. Where a Dermatologist feels that a mole is suspicious, they will recommend a biopsy of surgical removal.
How does a dermatologist treat Moles?
Moles are harmless and therefore most moles do not require treatment. If, however, the mole is causing physical or emotional discomfort, or there is a suspicion of melanoma, it is possible for a dermatologist to remove the mole(s), using one of the following procedures:
Surgical excision: This is where the entire mole is cut off by the dermatologist, and the skin stitched closed. If melanoma is suspected, it will be sent for the laboratory to be examined under a microscope.
Surgical shave: The mole is shaved off using a surgical blade.
Electrosurgical destruction (hyfrecation): This is where alternating electric current at various voltages is passed through the skin to generate heat, and destroy the skin growth.
Laser removal: While lasers can be used to remove moles, Dermatologists typically prefer not to use a laser as there is no pathology retained for future reference if malignant lesions are identified at a later time