TranscriptDr. Mayzik Moles, also called nevi, are growths on the skin. They occur when melanocytes, cells that make the pigment or color of the skin, grow in a cluster with tissue surrounding them. Dr. Patel, can you tell us more about moles? Dr. Patel Sure, Dr. Mayzik. Moles are quite common, and most people have between 10 and 40 moles. They are usually pink, tan, or brown, and they can be flat or raised. They are generally round or oval and no larger than a pencil eraser. About one out of every 10 people has at least one unusual mole that looks different from an ordinary mole. The medical term for these atypical moles is dysplastic nevi. People who have several dysplastic nevi may be more likely to develop melanoma, a less-common but more aggressive type of skin cancer. New moles may develop from time to time, usually until about age 40. Be sure to have a healthcare professional check new moles that develop. It’s also important to get new and existing moles checked if they are asymmetric, have an irregular border, vary in color, are larger than six millimeters in diameter, or are changing or evolving.