SKIN CANCERS & CONDITIONS
Dysplastic moles
A dysplastic mole is a common mole which is irregular in appearance and may resemble a melanoma.
- Dysplastic moles are common and rarely develop into melanoma
- People with multiple dysplastic moles have a high risk of developing melanoma
- On examination, they resemble melanomas and need to be biopsied to conform the diagnosis
A dysplastic mole, sometimes known as a dysplastic naevus, Clark naevus or atypical naevus, is a common but harmless odd-looking spot.
What does a dysplastic mole look like?
This type of mole often has visible features that also appear in melanoma, a serious type of skin cancer. It may be pigmented, asymmetrical in shape and with multiple colours. Usually a dysplastic mole will look different from the surrounding normal moles.
These features are often seen in melanoma, so it can sometimes be 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.
MBBS, MA (Virtual Comm), Grad Cert Hlth Info, Grad Dip Comp Inf Sci
Dysplastic mole on a man's back
Overview of a man's back with multiple dysplastic moles
Finger pointing at a dysplastic mole
Progression of dysplastic moles
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”.1
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 excision. In most cases, in order to make the diagnosis, 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.2
Melanoma risk
People with many dysplastic moles have an above-average risk of developing melanoma in future.
The risk of melanoma is up to 10 times greater for individuals with more than 5 dysplastic moles compared with those who have none.3
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.
Treatment of dysplastic moles
Dysplastic naevus is treated by surgical excision, with a clear margin of normal skin around all edges.
References
- Rosendahl C, Grant-Kels J, Que S, 2015. Dysplastic nevus: Fact and fiction. Journal of the American Academy of Dermatology, volume 73 issue 3, pages 507-512, 1 September 2015.
- Hocker T, Alikhan A, Comfere N et al, 2013. 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.
- National Cancer Institute, 2022. Common moles, dysplastic nevi, and risk of melanoma.
After a diagnosis of dysplastic mole
Regular check-ups will help detect new dysplastic moles or melanomas
Check your skin regularly for signs of melanoma. Be alert for “ugly duckling” spots which don’t resemble your other spots or moles.
Due to a higher risk of melanoma, have a yearly full body skin check with an experienced skin cancer doctor.
If you have many moles and find it difficult to keep track of them all, consider mole mapping photography.
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