While rare, sometimes people are born with certain anomalies that may or may not be noticeable. We've covered, for example, kids who are born with extra limbs or fingers and need to be operated on to get rid of them. It's estimated that somewhere between 0.4 and 6% of women are born with an extra breast or even pairs of breasts. Most of them do not develop fully.
The tissue is often misdiagnosed as being lymphatic or cystic. They're usually located in the lower armpit and are known as accessory breasts. Yet some others are born with an extra nipple or nipples, usually located under the breasts. While it's an oddity, neither the extra nipples nor the accessory breasts need to be removed in usual circumstances.