Dysplastic nevi or “Atypical” moles can be larger than common moles, irregularly shaped and of multiple colors. These generally large atypical moles are an important risk factor for Melanoma.
Atypical moles have the following characteristics.
- Shape: They are often asymmetrical: A line drawn thought the middle of the mole would not create matching halves.
- Border: The border of the mole is irregular and/or hazy. The mole will gradually fade into the surrounding skin.
- Color: The mole will have a variation in color. It can be irregular with subtle haphazard areas of tan, brown, dark brown, red, blue, or black.
- Diameter: These moles are generally larger than 6mm (1/4 inch) approximately the size of a pencil eraser but, they can be smaller.
Atypical moles are most often found on the back, chest, abdomen and extremities. They can also appear on normally unexposed areas such as the buttocks, groin, breast or scalp. The enlargement of a previously stable mole or the appearance of a new mole after the age of 35 should be checked by a dermatologist. The surface of these atypical moles is often raised in the center. The appearance of these moles is greatly varied. Dysplastic nevi often look very different from each other. Having numerous moles, atypical or normal, is also a risk factor for melanoma.
Atypical nevi can be similar in appearance to melanoma. Your dermatologist may use a dermatascope to determine which nevi are atypical during your exam. A biopsy is usually performed on the moles that are atypical. A dermapathologist will examine the biopsy under a microscope. Atypical moles are usually diagnosed as mild, moderately or severely atypical. Depending on the diagnosis, an atypical nevus may need a re-excision to assure that the margins are clear.
Mole mapping, use of serial photography, is an effective method of monitoring changes in the skin over time. Atypical moles should be monitored by self-exam and periodic, regular skin exams with your dermatologist.