Why Some People Have a Third Nipple

Characteristics of Supernumerary Niplles

Lady in shower after finding a third nipple
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Third nipples are common, though they often go undetected or are thought to be moles. They form during development in the uterus. and may occur anywhere along the "milk lines" from just above the armpit to the groin. Most often third nipples occur alone, but may sometimes be associated with congenital disorders of the heart or kidneys. While third nipples do not increase the risk of breast cancer, the tissue of third nipples as well as underlying breast tissue when present is subject to cancer as are normal breasts. Removal is not needed except when a person desires such for cosmetic reasons.

Common Names for Third Nipples

Extra nipples may be described in a number of ways, such as

  • Supernumerary nipples
  • Accessory nipples
  • Ectopic nipples
  • Triple nipples
  • Vestigial nipples
  • Witch's nipples

When an extra nipple (or nipples) occur alone, the condition is referred to as polythelia. When the third nipple is connected to breast (mammary) tissue and glands, it is called polymastia.

Breast Development and Extra Nipples

The breasts develop early on in an embryo's development, typically during the fourth week of gestation. What are known as milk lines appear soon after, at around the sixth week of development. These arch down from the armpit to the groin on both sides of the body. As the breasts continue to develop, these lines eventually disintegrate, usually by about week nine. 

Occasionally, however, milk lines will persist and may be connected to extra breast tissue and extra nipples. Extra nipples that are connected to breast tissue may sometimes produce breast milk after pregnancy.

Extra or supernumerary nipples are usually smaller than regular nipples.

Incidence and Characteristics

Both men and women can develop an extra nipple. It is a fairly common abnormality affecting roughly 1 in 20 people. It sometimes occurs in families but is more likely to develop at random.

Anne Boleyn, the wife of King Henry VIII of England, was said to have had a third nipple. Scaramanga, an infamous Bond villain, had an accessory nipple and this was what made him easy to identify. Scientists named the Scaramanga gene after him; it is this gene that produces a protein called Neuregulin-3 (NRG3), which provides a signal to embryonic cells telling them to become breast cells.

Types

There are six main categories of third nipples:

  • Category 1: A third nipple and areola is present with underlying breast tissue (polymastia)
  • Category 2: The third nipple does not have an areola but does have underlying breast tissue
  • Category 3: Breast tissue and an areola is present but a nipple is not
  • Category 4: Breast tissue is present but there is not a nipple or areola
  • Category 5: A nipple and areola are present with fatty tissue beneath, but not breast tissue
  • Category 6: A nipple is present without an areola or underlying breast tissue (polythelia)

Breast Cancer Risk

If you have one or more extra nipples, you may wonder if this increases your risk for breast cancer. Any breast tissue you have, whether it appears in the standard location or elsewhere, is vulnerable to the same diseases that can affect typical breast tissue. Extra nipples that occur alone (are not attached to breast tissue) may uncommonly be affected by a cancer of the nipples known as Paget's disease. Paget's disease of the nipple can sometimes also show up in the groin area (lower end of the milk lines) where it is called extramammary Paget's disease (EMPD).

Associated Conditions

Third nipples are medically considered to be a minor birth defect. While they most often occur alone, and sometimes run in families, they are sometimes linked to other birth defects (congenital disorders) involving the heart or kidneys.

Caring for Third Nipples

In most people, extra nipples are benign and may never be noticed. But if you know that you have a third nipple, talk to your doctor if you note any changes such as dryness or flakiness, a rash, or a lump.

Not all nipple changes indicate breast cancer, but knowing which are expected changes and which are signs of disease is critical to your breast health.

Removal

Third nipples do not need to be removed, but sometimes people wish to have these removed for cosmetic reasons. Surgical procedures will vary depending on whether the third nipple is associated with underlying breast tissue.

Isolated third nipples can be removed via a simple procedure, similar to removal of a mole. For supernumerary nipples connected with breast tissue, a mastectomy (removal) can be done.

Genetic Testing

Now that genetic testing is available for some familial breast cancers, it's important for people to be aware of third nipples (at least those associated with breast tissue), as these areas will need to be monitored (or removed) along with the two "normal" breasts.

A Word From Verywell

Third nipples are common, but often go undetected or are thought to be moles. Most often, they are not associated with any underlying problems and do not need any special attention, but it's important to talk to your doctor if you believe you may have an extra nipple.

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Article Sources
  • National Institutes of Health. Supernumerary Nipple. Updated 02/07/2017.

  • Kliegman R., Stanton, B., St. Geme J., and N. Schor. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016