Atypical Mole Syndrome

What is atypical mole syndrome?

Atypical mole syndrome is a disorder of the skin which is seen in approximately 2% of the population. It is defined as where an individual has a collection of more than 50 moles composed of melanocytes (cells able to produce pigment) present on their bodies, whereby three or more are atypical (unusual) in their appearance, e.g. size and structure. An atypical mole is one greater than 5mm in diameter, often with flat and raised areas, often oval rather than round, and often with some colour variation.

Solitary atypical moles are individually benign moles with a low risk of progression to melanoma (which is a type of skin cancer). However, people with multiple atypical moles (atypical mole syndrome) are considered to have a higher risk (increased 7 to 10 fold) of developing melanoma and skin cancer compared to the general population, due to the presence of atypical moles especially if some of these moles are on the scalp, buttocks, or the back of the feet. The risk is increased further if one or more first or second degree relatives (i.e. a close blood relative including parents, full siblings or children, or a blood relative including grandparents, grandchildren, aunts, uncles, nephews, nieces or half-siblings, respectively) have been diagnosed with malignant melanoma; this combination is known as familial atypical mole syndrome.

What causes atypical mole syndrome?

It is likely that both genetics and UV radiation have a role to play in development of atypical moles. The Caucasian population, especially Celtic (fair-skinned) people, are much more prone to developing multiple atypical naevi, whereas the condition is rare in other ethnic groups.

Is atypical mole syndrome hereditary?

Yes, it is a hereditary condition; however, it may also occur sporadically with no family history.

What are the symptoms of atypical mole syndrome?

There may be no adverse symptoms at all with atypical mole syndrome, other than the appearance of the moles themselves. It is also possible for new moles to appear over time, for existing moles to itch, become crusted or inflamed, or for a mole to change in size, shape or colour.

What does atypical mole syndrome look like?

As mentioned above atypical mole syndrome is where an individual has a collection of melanocytic naevi, whereby three or more are atypical (unusual) in their appearance.

Atypical moles are generally larger than normal moles (greater than 5mm in diameter), and have irregular borders and some asymmetry meaning that they are often oval rather than round. Their colour varies from pink to dark brown and they are usually flat or slightly raised from the surface of the skin. They can be positioned on any part of the body, but are most commonly found on sunexposed areas such as the scalp, upper limbs and trunk. Atypical moles may resemble a melanoma in appearance; however, they do not have other features of melanoma such as persistent and ongoing change.

How is atypical mole syndrome diagnosed?

Atypical mole syndrome can often be recognised by its appearance, if examined by a dermatologist. If there are any concerns over the diagnosis your doctor can arrange for the mole to be removed and examined. A set of baseline photographs of the entire skin surface may be requested to facilitate monitoring of the moles.

People who have atypical mole syndrome, or familial atypical mole syndrome, are at an increased risk of developing melanoma and therefore it is recommended that the skin is checked, on a regular basis, for any changes (as mentioned under the Self care (What can I do?) section).

Can atypical mole syndrome be cured?


How can atypical mole syndrome be treated?

An individual atypical mole can be removed surgically if the dermatologist is concerned about it. However, most moles will not require removal, and any surgical procedure carried out will, inevitably, leave a scar.

Self care (What can I do?)

Second only to dermatologists, many patients identify skin cancers, including melanoma, themselves.

Check your skin for changes once a month. A friend or family member can help you, particularly with checking areas that you cannot easily inspect such as your back.

Top sun safety tips:

  • Protect your skin with clothing, and don’t forget to wear a hat that protects your face, neck and ears, and a pair of UV protective sunglasses.
  • Spend time in the shade between 10am and 3pm when it’s sunny. Step out of the sun before your skin has a chance to redden or burn. Keep babies and young children out of direct sunlight.
  • When choosing a sunscreen look for a high protection SPF (SPF 30 or more) to protect against UVB, and UVA . Apply plenty of sunscreen 15 to 30 minutes before going out in the sun, and reapply every two hours and straight after swimming and towel-drying.
  • Keep babies and young children out of direct sunlight.
  • Tell your doctor about any changes to a mole. If your GP is concerned about your skin, he or she can refer you to a Consultant Dermatologist
  • Sunscreens should not be used as an alternative to clothing and shade, rather they offer additional protection. No sunscreen will provide 100% protection.
  • It may be worth taking Vitamin D supplement tablets (available from health food stores) as strictly avoiding sunlight can reduce Vitamin D levels.

Vitamin D advice: The evidence relating to the health effects of serum Vitamin D levels, sunlight exposure and Vitamin D intake remains inconclusive. Avoiding all sunlight exposure if you suffer from light sensitivity, or to reduce the risk of melanoma and other skin cancers, may be associated with Vitamin D deficiency.

Individuals avoiding all sun exposure should consider having their serum Vitamin D measured. If levels are reduced or deficient they may wish to consider taking supplementary vitamin D3, 10-25 micrograms per day, and increasing their intake of foods high in Vitamin D such as oily fish, eggs, meat, fortified margarines and cereals. Vitamin D3 supplements are widely available from health food shops.

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