[header] How to examine a mole [title] Look for atypical moles. [step] The main way to tell if a mole is atypical is to know the difference between them and normal moles. Atypical moles, also known as dysplastic nevi, are most commonly seen on the chest and back. 
These moles are usually greater than 6 mm in diameter and have more than two shades of brown or black on them. They look different than normal moles because their margins are irregular and, in most cases, they have a raised center, which is called a " fried-egg " appearance.