Explanation: The patient has a supernumerary nipple. Found in 1-6% of the general population and change with pregnancy and puberty in women. Histology shows smooth muscle, pilosebaceous ducts. There is no increased malignant potential but examination such as mammography or ultrasound has been recommended as with other breast tissue. Routine renal imaging is not recommended.
Reference: Dermatology. Bolognia, Jorizzo, Schaffer. 3rd ed. Ch 64.