Abnormal or atypical moles are often larger than a dime, asymmetrical or not round in shape, and appear as a mixture of colors including red, pink, tan, and brown. Atypical moles are known as dysplastic nevus. Some dysplastic nevus can resemble melanoma, even if they are not cancerous. However, the risk of getting melanoma increases when you have at least four atypical moles.