While the vast majority of moles are benign and remain that way over an individual’s lifetime, some do progress to become melanoma, a type of skin cancer. It is important to monitor moles for changing appearance and behavior over time. A useful tool for monitoring moles for suspicious characteristics is the ABCDE method:
Asymmetry: If you draw a line through the mole, the two halves do not match.
Border: Uneven or notched border as opposed to a smooth one.
Color: Different shades of brown, black, blue, pink and/or white in the same mole.
Diameter: Greater than 6 mm, or the size of a pencil eraser.
Evolving: Rapid changes in the above characteristics.