Why Some People Have a Third Nipple

Third nipples are common, although people don't always know what they are. Many times, they go undetected or are mistaken for moles or birthmarks. They're typically harmless, but because extra nipples sometimes are accompanied by breast tissue, they should be monitored for breast cancer.

Read on to learn about extra nipples, why they develop, and their potential complications.

nipple variations
Verywell / JR Bee

Overview

Extra nipples form in utero and can occur anywhere along the milk lines. These are lines on both sides of the front of the body, from just above the armpit to the groin, where breast tissue can potentially appear.

Third nipples typically occur alone but can be associated with various medical conditions. When an extra nipple (or nipples) occurs alone, the condition is referred to as polythelia. When the third nipple is connected to breast (mammary) tissue and glands, it's called polymastia.

Third nipples should be examined at the same frequency as normal breast tissue, as they are susceptible to the same diseases. Removal isn't usually needed other than for cosmetic reasons or if the nipple causes discomfort.

Third nipples are sometimes referred to as:

  • Supernumerary nipples
  • Accessory nipples
  • Ectopic nipples
  • Triple nipples
  • Vestigial nipples

Types

There are six main categories of third nipples. These types are categorized depending on size, shape, and tissue makeup. They can include:

  • Category 1: A third nipple and areola is present with underlying breast tissue (polymastia).
  • Category 2: The third nipple doesn't have an areola, but does have underlying breast tissue.
  • Category 3: Breast tissue and an areola are present, but a nipple is not.
  • Category 4: Breast tissue is present, but there's no 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).

In some cases, people have more than one third nipple (supernumerary nipple) and these can be of different types.

Why Third Nipples Occur

The breasts form early on in an embryo's development, typically during the fourth week of gestation. Milk lines, the first evidence of mammary gland development, appear soon after, at around the sixth week of development. These ridges 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.

Supernumerary nipples are usually smaller than regular nipples.

Hereditary or Random Occurrence?

Third nipples can be hereditary, but are more likely to be a random phenomenon.

Potential Complications

If you have one or more extra nipples, you may wonder if this increases your risk for breast cancer. The answer is yes, potentially. Any breast tissue you have is vulnerable to the same diseases that can affect typical breast tissue, no matter where it may be.

A possible link between supernumerary nipples and BRCA2 gene mutations was proposed in a 2017 study in which a brother and sister both had breast cancer, BRCA2 mutations, and bilateral supernumerary nipples. While an association is unknown at this time, those who have third nipples may consider asking their relatives about the presence of third nipples or any genetic testing for cancer risk they have done. BRCA2 mutations are well known to increase the risk of breast cancer.

Extra nipples that occur alone (not attached to breast tissue) may uncommonly be affected by a cancer of the nipples known as Paget's disease of the nipple. Paget's can sometimes also show up in the groin area (at the lower end of the milk lines), where it is called extramammary Paget's disease (EMPD).

There may be other potential complications if you have a third nipple. Supernumerary nipples have been associated with kidney and urinary tract malformations, heart arrhythmias, hypertension, peptic ulcer disease, migraine, testicular cancer, and more. Polythelia (category six) is also associated with a higher risk of genitourinary cancers, as well as renal cancers.

When to See Your Healthcare Provider

In most people, extra nipples are benign and because they often occur below the breast, may never be noticed. But if you know you have a third nipple, talk to your healthcare provider 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.

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. These areas will need to be monitored along with the two "normal" breasts, and considered when developing any treatment plans.

Removal

Third nipples don't usually need to be removed, but sometimes people wish to have them removed for cosmetic reasons or if they cause discomfort. Surgical procedures will vary depending on whether or not the third nipple is associated with underlying breast tissue.

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

Summary

Third nipples are a fairly common occurrence, although many people may not be aware that's what they have. Most often, they're not associated with any underlying problems.

While they don't increase your risk of breast cancer, they may be at risk for any disease that typical breasts may develop. Third nipples are also associated with various medical conditions and other types of cancer, so it is important to go for regular check-ups.

Third nipples are common, but often go undetected or are thought to be moles. But if you believe you may have an extra nipple it's important to bring it to your healthcare provider's attention.

Frequently Asked Questions

  • Is having a third nipple a sign of a health problem?

    Not necessarily. Being born with an extra nipple is actually fairly common. It doesn't usually cause any symptoms or other complications. In some instances, it may occur with kidney or heart disorders. You should have the area around the nipple checked for breast-related diseases if there is breast tissue present.

  • How common is it to have an extra nipple?

    Up to 1% of people are born with an extra nipple that is connected to mammary tissue. Up to another 2.5% of people have a nipple that exists alone without breast tissue.

  • Why does my baby have an extra nipple?

    There's no known cause for polythelia, which is when a baby is born with an extra nipple. The extra nipple forms during the baby's development in the uterus. It may run in families, but researchers have not determined if there is a definite hereditary link.

Originally written by
Pam Stephan
Pam Stephan is a breast cancer survivor.
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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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