File this one under – "If it works for specialists it can work for you."
A recent study found that looking for the "ugly duckling sign" in moles was a reliable way to identify malignant melanoma, aka skin cancer. The ugly duckling moles are those moles that don't follow the pattern of a person's moles; these stick out in their difference in pigmentation. Unlike the age-old fable, these ugly ducklings do not turn into swans.
If you have a mole with different coloring from your other moles, go and see a dermatologist! You should have your skin screened regularly, starting at age 30. The earlier a problem is detected the better!
"One of theses things is not like the other. One of these things just doesn't belong."