In rare cases, polythelia can be a sign that you have a malignant tumor or congenital breast defect. It may also be a sign of breast cancer. Polythelia can also be associated with serious kidney conditions such as end-stage renal disease. It may also be a sign of cancer of the kidney cells. Extra nipples that are not connected to breast tissue may also be at higher risk of developing Paget’s disease of the nipple, a rare form of breast cancer where cancer cells are located on the areola and the nipple’s surface.