Most of the time, nipples on the breast point outward. Sometimes a nipple lays flat against the areola, known as a retracted nipple. But sometimes, nipples can point inward, which is referred to as inverted nipples, or nipple inversion.
Inverted nipples are pretty common. Up to 20% of men and women have them, says breast medical oncologist Jason Mouabbi, M.D.
What causes inverted nipples? And can they ever be a sign of a serious medical condition like breast cancer? We spoke with Mouabbi for answers to these questions and more.
What causes inverted nipples?
Half of all inverted nipples are due to congenital causes, meaning it’s a trait you’re born with. So, if 20% of the general population has inverted nipples, half of that population, or 10% of the total population, have them due to congenital causes.
“An easy way to tell if inverted nipples are congenital is to see if the inverted nipples are bilateral, or affecting both breasts,” says Mouabbi. “About 90% of congenital inverted nipples affect both breasts.”
Some people have acquired nipple inversion, which can occur any time after birth. It has many possible causes, including:
Trauma – e.g., if you brake hard while driving and the seatbelt tightens across your chest
Infection – e.g., mastitis, an inflammation of the breast
Rapid weight loss – When the fatty tissue right behind the nipple is lost, the nipple can sink in, or invert.
Aging – As you age, your breast loses structures and starts to sag. This can also cause nipple retraction.
Are inverted nipples ever a sign of breast cancer?
Yes, inverted nipples can be a sign of breast cancer in both men and women. Here are some indicators that nipple inversion could be cancer.
It affects only one breast.
It happens suddenly.
It has one or more of the following associated symptoms:
discharge from the nipple, particularly if it’s bloody or has a yellowish hue
breast skin dimpling, resembling an orange peel
“If you have any of these symptoms, see your physician right away,” says Mouabbi. “The doctor will discuss your history to see if there was trauma or an event that may have led to the nipple inversion. And they’ll do a physical exam.”
During a physical exam, your doctor can feel for any lumps and squeeze the nipple to see if there’s discharge as well as the color. They may also order a mammogram and breast ultrasound to further examine the breast.
“You can identify inverted nipples on a mammogram, and we can also see if there’s any scar tissue,” says Mouabbi.
Are inverted nipples associated with a particular type of breast cancer?
Paget disease of the breast is a rare type of ductal cancer that accounts for 1% to 4% of breast cancer cases. The disease first appears on the nipple and often extends to the areola.
“Paget disease is contained inside the duct and is therefore considered as stage 0 breast cancer,” says Mouabbi. “The nipple is an extension of the breast ducts. What happens is the cancer cells inside the ducts get closer to the nipple and begin to pull on it, which causes the inverted nipples.”