A type of mole that looks different from a common mole. Several different types of moles are called atypical. Atypical moles are often larger than common moles and have regular or ragged or blurred borders that are not easy to see. Colors of atypical moles may be the same as the rest of the skin, or lighter, darker, or uneven. Parts or all of the mole may be raised above the skin surface. It is rare, but some atypical moles can develop into melanoma (a type of skin cancer). An atypical mole is sometimes called a Spitz nevus, a congenital nevus, a birthmark, or a dysplastic nevus.