However, biopsy and histologic evaluation should be considered if moles have certain characteristics of concern (known as the ABCDEs of melanoma): A: Asymmetry—asymmetric appearance B: Borders—irregular borders (ie, not round or oval) C: Color—color variation within the mole, unusual colors, or a color significantly different or darker than the patient's other moles D: Diameter—> 6 mm E: Evolution—a new mole in a patient > 30 years of age or a changing mole Patients at risk can be taught self-examination to detect changes in existing moles and to recognize features suggesting melanoma.