Multiple breasts. Polymastia is a big word for having more than two breasts. If someone has this condition, they can had an extra breast anywhere from the armpit along a line through the normal breast, down into the groin. Not uncommonly men or women can have an extra, or supernumerary nipple, under the natural breast. It may look like a mole. Some women may not know they have accessory breast tissue until pregnanc.