Accessory breast
Accessory breasts, also known as polymastia, supernumerary breasts, or mammae erraticae, is the condition of having an additional breast. These extra breasts may appear with or without nipples or areolae. The condition, a form of atavism, is most commonly observed in males and is generally harmless, often going untreated. However, in recent years, many affected women have had a plastic surgery operation to remove the additional breasts, for purely aesthetic reasons.
A related condition, in which extra nipples form, is called "supernumerary nipple" or "polythelia".
Presentation
In some cases, the accessory breast may not be visible at the surface. In these cases, it may be possible to distinguish their appearance from normal breast tissue with MRI. In other cases, accessory breasts have been known to lactate, as illustrated in a drawing showing a child nursing at ectopic breast tissue on the lateral thigh.There is some evidence that the condition may be more common in Native American populations.