What Is Dysplastic Nevus Syndrome?
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Dysplastic Nevus Syndrome - Causes, Symptoms, and Treatment

Published on May 09, 2023 and last reviewed on Jun 05, 2023   -  4 min read


Atypical mole syndrome is a rare disorder in which a person has an abnormally high number of moles on their skin.


Atypical mole syndrome is also called dysplastic nevus syndrome. Atypical moles are larger, grow faster, and are darker than normal moles. These indicators make it easier for doctors to identify the syndrome. Read on to learn more about atypical mole syndrome and how you can protect yourself from developing it.

What Is Dysplastic Nevus Syndrome?

Dysplastic nevus syndrome is an autosomal dominant condition that results in the appearance of distinctive blue or purple-colored birthmarks called nevi. These lesions are larger than ordinary moles and develop from pigment cells called melanocytes. The unique feature of this condition is the development of multiple or larger-than-normal moles at some point in life for most individuals with dysplastic nevus syndrome. The presence of dysplastic nevi indicates a greater degree of risk for developing melanoma and also other types of skin cancer. However, the presence of these lesions does not mean that an individual will definitely get cancer but instead increases the risk. Normal moles are different from atypical moles, and they are usually round and yellowish brown in color, occupying not more than a third of the skin surface on any location such as the back or arms. They appear at an early age and do not change significantly in size or shape over time.

What Are the Causes of Dysplastic Nevus Syndrome?

Dysplastic nevus syndrome is a genetic condition that affects about one in every 10,000 people. There are several theories about what causes dysplastic nevi. Some scientists believe that abnormal regulation of the development of cells in the skin causes moles in people with dysplastic nevus syndrome. Another theory is that the person has skin that is more sensitive to ultraviolet (UV) light than normal individuals. This means that a person with DNS has a greater chance of getting skin cancer when exposed to UV light than other people. Dysplastic nevus syndrome is common among people with a family history of this condition.

What Are the Symptoms of Dysplastic Nevus Syndrome?

Most people with dysplastic nevi have no symptoms. However, depending on the extent of the condition, these moles cause itching or irritation. Many people with dysplastic nevus syndrome have freckles, and some have dysplastic nevus syndrome with multiple keratotic erythemas which are red, scaly patches that sometimes appear on the palms of the hands or soles of the feet.

What Are the Risk Factors of Dysplastic Nevus Syndrome?

The exact cause of dysplastic nevus syndrome is not known, but researchers believe that it is due to a combination of genetic as well as environmental factors such as sun exposure. If you or a family member has a history of dysplastic nevi, one may be diagnosed with dysplastic nevus syndrome.

How Is Dysplastic Nevus Syndrome Diagnosed?

Dysplastic nevus syndrome is diagnosed by physical examination of the skin and looking for distinctive blue, purple, or red patches on the skin. A biopsy is the only way to confirm the diagnosis of dysplastic nevus syndrome. This involves removing a sample of skin and checking it under a microscope for abnormal cells.

What Is the Treatment of Dysplastic Nevus Syndrome?

There is no need to remove these moles if they are not changing because they are not cancerous. Atypical moles may instead signal a higher risk of melanoma skin cancer. Therefore, it is advised that people with atypical moles undergo routine skin examinations with a physician. Current treatments for dysplastic nevus syndrome focus on the prevention of skin cancer caused by moles. Dysplastic nevus syndrome is usually treated with surgery to remove moles from the skin. During the procedure, a dermatologist or general surgeon removes all of the moles and closely examines them to see if they are atypical.

How to Deal With Dysplastic Nevus Syndrome?

Unfortunately, there is no way to prevent dysplastic nevus syndrome from developing later in life. People with a family history of dysplastic nevus syndrome may want to watch out for signs of this disorder, such as having hundreds of moles on their skin and moles that are larger than normal and are dark brown or black in color.

Most individuals with dysplastic nevus syndrome do not need any treatment. However, individuals with dysplastic nevi should take appropriate precautions to minimize their risk of developing skin cancer. These include staying out of the sun and wearing sunscreen as well as clothing and hats that protect the skin. People who have dysplastic nevus syndrome should have their skin examined by a dermatologist every year or every other year to check for skin cancer.

What Is the Importance of Genetic Counseling?

Due to the potential health implications of dysplastic nevus syndrome and the possibility of passing it on to children, individuals who test positive for dysplastic nevus syndrome should consult with a genetic counselor. Besides discussing the implications of dysplastic nevus syndrome on an individual’s life, genetic counselors can also provide advice on how to proceed with the pregnancy, particularly in the case of women who want to become pregnant.

Typically, doctors will recommend that pregnant women over the age of 30, who are at a higher risk of having a child with dysplastic nevus syndrome, undergo genetic testing of the fetus. Genetic counselors can also offer advice on how to manage the condition to minimize the risks. Finally, individuals with dysplastic nevus syndrome may also want to discuss with a genetic counselor whether they should inform their partner of the condition and their family members.


Dysplastic nevi are usually harmless, but they should be monitored regularly, especially in individuals who have a family history of melanoma. If you are at a higher risk of developing skin cancer and notice changes in the size or color of your moles, you should make an appointment with a dermatologist. If an individual is diagnosed with dysplastic nevus syndrome, talk to the doctor about ways to minimize the risk of skin cancer. With early detection, one can keep track of any changes to the moles and catch any that are atypical as soon as possible. This will make it easier to treat any moles that need medical treatment.

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Last reviewed at:
05 Jun 2023  -  4 min read




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