In about 5% of children, additional nipples, areolas, and sometimes a true accessory breast may develop anywhere along the breast line from the axilla to the pubis. 

They are most commonly located on the chest wall below the actual breast. Unsightly polythelia should be removed*, preferably after 10 years old.

* GW Holcomb, J Patrick Murphy, DJ Ostlie. Aschcraft´s Pediatric Surgery 6º Ed.