There are hundreds of different types of common and uncommon moles. Some are acquired and others occur at birth. Certain moles have a higher chance of developing into skin cancers. Mole screen mappings can detect new moles and measure those that are at risk for the development of skin cancer. Atypical or dysplastic moles were identified in melanoma-prone families. Malignant melanoma can arise from a pre-existing atypical mole. Some dysplastic moles are removed surgically to prevent any cancerous change from potentially developing.