The presence of accessory breast tissue such as extra nipples (polythelia) and extra breast (polymastia) is relatively common, with a high incidence of being misdiagnosed in clinical medicine. Although polythelia is congenital in origin and is identifiable at childhood, polymastia may not be evident until the influence of sex hormones during puberty. In this article, we present a review of the literature concerning the historical background of accessory breasts, their incidence, their misdiagnoses, and their association with other syndromes and diseases. Finally, we present the common treatment options available today for such conditions.