Accessory breasts and nipples in female are more of disfigurements than disease.These are developmental errors.In animals(including human) there develops one milk line stretching from the axilla to the abdomen on each side of body in a female fetus(while in the mothers womb).From these milk lines five to six rudimentary breasts with nipples formed to develop further to future full fledged breasts on either side of body.In lower animals these persists in form of more than one nipple to develop further in the later life for lactation as seen in dogs and cats.But in human all the nipple disappear to the time of birth leaving only one on each side of body on the chest to develop further in the reproductive life.Errors do occur.And sometimes more than one nipple remains on one or both sides and may develop further to lactate .Also some times an accessory breast also develops from the remnants in the milk line usually in the axilla without a nipple as a breast.It may enlarge further to cause pain called mastalgia or engorge with milk during lactation period.
These more of disfogurement and discomfort.And necessiates cosmetic removal and repair.
Image by grebo guru via Flickr
