Dysplastic Nevi

Dysplastic or dysplasia refers to the presence of unusual (abnormal) cells in tissue. Nevus is the medical term for a mole, a common type of skin growth. Nevi refers to multiple moles. Dysplastic nevus is a mole that looks different from most moles. It can have irregular borders, be a mix of colors and appear larger than other moles. Your doctor may use the term dysplastic nevi if you have multiple atypical moles. 

Atypical moles are benign (not cancerous), but they can progress over time to become cancerous. People with dysplastic nevi are more at risk for melanoma. About 1 in 10 Americans have at least one atypical mole. 

Types & Stages

Dysplastic nevi can be identified clinically as mild, moderate or severe:

• Mildly dysplastic nevi. These are moles that show a tendency to become much larger than a normal nevus. They have slight structural and cellular changes, such as minor asymmetry and changes like a “fried egg” appearance—a raised, darker center surrounded by a flat, lighter-colored rim. Mildly dysplastic nevi can be observed by your doctor.
   
• Moderately atypical nevi. Tend to be larger than the fried egg nevus and have irregular color in the center and more irregular borders. If you have many, they can be followed closely by your doctor or surgically removed if there are only a few. 
   
• Severely dysplastic nevus. These are indistinguishable from early melanoma. Very often they show considerable irregularity of the edges and color. The difference between a moderate and severely dysplastic nevus is one of degree. Severely dysplastic nevi should be surgically removed.

Signs & Symptoms

Dysplastic nevi are not cancerous but are considered precursors to melanoma. If you have a history of dysplastic nevi, you’re at increased risk for developing melanoma, especially if you have multiple atypical moles or a family history of melanoma.

• A mole may be a sign of skin cancer if it has irregular borders or an asymmetrical shape, or if it changes in color, shape, size or height. This ABCDE guide can help you remember what to watch for: 
   
  • A is for Asymmetry: One half of a mole or birthmark does not match the other.
     
  • B is for Border: The edges are irregular, ragged, notched or blurred.
     
  • C is for Color: The color is not the same all over and may include different shades of brown or black, or sometimes with patches of pink, red, white or blue.
     
  • D is for Diameter: The spot is larger than 6 millimeters across (about ¼ inch – the size of a pencil eraser), although melanomas can sometimes be smaller than this.
     
  • E is for Evolving: The mole is changing in size, shape or color.
     
• Also, moles can grow anywhere on your body. This includes your scalp and armpits, as well as under your nails and between your fingers and toes. Most people have 10 to 45 moles. Many of these moles occur by age 40. Moles may change or fade away over time. They may become darker and larger with hormonal changes that occur during the teenage years and while pregnant. In addition: 
   
  • Clusters of brown spots around the eyes, cheeks and nose are dermatoses papulosa nigra — a type of seborrheic keratosis that is noncancerous and appears as waxy brown, black or tan growths. They aren't clusters of pigment-forming cells, known as nevi. 
     
  • Dermatoses papulosa nigra are more common among Black women. These lesions don't carry a risk of melanoma, but they can be treated as a cosmetic concern.
     
  • Having a lot of atypical moles may put you at risk for ocular melanoma. This type of cancer develops in your eyes. You may need more frequent eye exams.

Diagnosis

A dermatologist diagnoses and treats skin diseases like skin cancer. Seeing a skin cancer specialist is important when you have atypical moles. Your doctor may perform:

• Skin examinations. They may suggest once or twice a year to check for changes to moles (or every three to six months if you have a family history of melanoma).
   
• Dermoscopy. Using a magnifying device called a dermatoscope your doctor will look for abnormalities in moles that are invisible to the naked eye.
   
• Mole mapping. Using a special camera with a dermatoscopic lens your doctor will create a computerized map of your skin and moles.

Treatment

An atypical mole doesn’t need further treatment unless a skin biopsy indicates cancer or pre-cancerous changes. Treatments for atypical moles involve surgically removing the mole and a small border of surrounding skin. 

If the biopsy shows cancer (melanoma) associated with the atypical mole, your doctor may perform a more extensive surgical removal or Mohs surgery. This is a precise, outpatient procedure to remove the skin cancer through layer-by-layer excision while preserving surrounding healthy tissue. 

Causes & Risk Factors

Experts aren’t sure why some people develop dysplastic nevi, but point to a combination of family history and environmental factors like ultraviolet (UV) light exposure from the sun and artificial light may play a role. Also, atypical moles can affect people of all ages, sexes and skin colors. Having dark skin doesn’t protect you from atypical moles or skin cancer, but your risk is reduced.

People with these risk factors are more likely to develop atypical moles:

• Family history. Family members who have had atypical moles, skin cancer or melanoma.
   
• Ultraviolet (UV) exposure. A history of unprotected exposure to ultraviolet (UV) radiation from the sun or indoor tanning. 
   
• Light skin. Moles occur far more frequently in people with light skin, especially if you tend to freckle or get sunburns. People with light eyes and hair are also at risk. 

Screening

With skin self-exams and skin checks by a health care professional like a dermatologist, problematic moles can often be found early. When skin cancers are found early, they are likely to be easier to treat.