Dysplastic naevus

A dysplastic mole is a common mole which is irregular in appearance and may resemble a melanoma. People with dysplastic moles have a higher risk of melanoma.

Also known as

Clark naevus, atypical mole, dysplastic mole, atypical naevus

Symptoms and signs

  • Irregular, asymmetrical pigmented patch on the skin. Usually a dysplastic mole will look different from surrounding normal typical moles.

Risk factors

  • Genetic predisposition
  • Multiple moles

Prognosis / outcome

Dysplastic moles are harmless and theoretically do not require treatment. However, on clinical examination it can be difficult to tell the difference between a dysplastic naevus and an early melanoma, so they are often surgically removed.

Progression

Dysplastic moles were once believed to progress to melanoma if untreated. Although melanomas sometimes develop in dysplastic moles, the risk is in fact no higher than in a normal/typical mole. However, people with multiple dysplastic moles have an above-average risk of developing future melanomas.

Procedures for

 

Dysplastic naevus

Medications for

 

Dysplastic naevus

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Prevention of

 

Dysplastic naevus

  • There is no known way to prevent the development of dysplastic moles
  • People with multiple dysplastic moles may have an increased risk of developing future melanomas. They should have a yearly full body skin cancer check performed by an experienced doctor, nurse or other health professional. Of there are more than 200 moles, regular total body photography (mole mapping) may be recommended.

More information

News / blog articles

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Recommended web links

Clinical images of
Dysplastic naevus
Click on an image to view it in greater detail.

A dysplastic naevus (mole) is a common but harmless odd-looking spot. This type of mole often has visible features that also appear in melanoma, a serious type of skin cancer. It’s sometimes very difficult for a doctor to know if a spot is a dysplastic mole or a melanoma when examining it, even with a dermoscope to magnify it. This means that dysplastic moles often have to be biopsied so that a correct microscopic diagnosis can be made. Even though a dysplastic mole looks suspicious on examination by your skin cancer doctor, there are no melanoma changes when it's examined microscopically.

We used to think that dysplastic moles would eventually turn into melanoma if untreated. The result was that people used to have lots of odd-looking moles removed as a “precaution”. We now know that it's unusual for any longstanding pre-existing mole to later develop into a melanoma. Having lots of dysplastic moles removed doesn’t reduce the risk of later developing a melanoma.

The treatment for a dysplastic mole is surgical removal, or excison. In most cases, the mole has already been removed. Sometimes when a dysplastic naevus is diagnosed, your doctor will decide to re-excise more widely around the original spot. Research has shown that this is rarely necessary. A recent study has shown that over many years of follow-up, narrowly-excised dysplastic moles did not re-grow as melanomas.

People with many dysplastic moles have an above-average risk of developing melanoma in future. For this reason, if you’ve ever had a dysplastic mole, you should consider having a full body skin cancer check every year in future, possibly with mole mapping if you have more than 100 moles.

References

Hocker T, Alikhan A, Comfere N et al
Favorable long-term outcomes in patients with histologically dysplastic nevi that approach a specimen border
Journal of the American Academy of Dermatology volume 68, issue 4, pages 545-551, 1 April 2013
2013
https://doi.org/10.1016/j.jaad.2012.09.031
Date accessed:
July 22, 2021
Rosendahl C, Grant-Kels J, Que S
Dysplastic nevus: Fact and fiction
Journal of the American Academy of Dermatology, volume 73 issue 3, pages 507-512, 1 September 2015
2015
https://doi.org/10.1016/j.jaad.2015.04.029
Date accessed:
July 22, 2021