What is a Mole? A mole,
whose medical name is a melanocytic nevus, is an common benign growth
of the color cells of the skin called melanocytes.
Moles normally appear in the first year of life and peak in number
in the second or third decade, when the average number is 25. The
total number of moles on the skin increases with significant sun exposure
and in particular with sunburns before the age of 12. Some moles may
disappear in the seventh to ninth decade.
The number of moles on your body is the strongest indicator for the
risk of developing a malignant melanoma. There is also a direct relationship
between the number of innocent moles on the skin and the chance of
developing an abnormal or changing mole.
The number of moles on the arms is the greatest predictor of the number
of moles present elsewhere on the body. Chronically sun exposed body
sites have a higher density of moles, in particular small ones less
than 5 mm in diameter. Larger moles are most prevalent on intermittently
sun exposed areas, like the back and chest. Moles may increase in
size, particularly before the age of 20. Normal moles are unlikely
to enlarge as people get older. However, enlargement alone is not
an indicator of malignancy or abnormality in a mole.
Here are two examples of patients with multiple atypical nevi:
Click on the thumbnail photo for a much larger image.
1. This patient has had malignant melanoma. His moles demonstrate
the variation, size and appearance and color that are seen in patients
who have multiple moles, and are at increased risk of developing malignant
melanoma. These moles range in size from 1 mm to more than 1.5 cm.
Some are irregular in color, and vary from light pink to dark brown.
Most demonstrate symmetry.
2. This patient shows multiple large nevi, which have features of
atypia. There is a large number of large nevi, with variation in appearance,
which is a hallmark of patients at risk of melanoma.