Understanding Adenomas of the Breast: Symptoms and Treatment

Breast adenomas are benign tumors that grow in the thin layer of tissue that lines surfaces inside of the breast. Sometimes they don’t cause any issues and go away on their own. But sometimes they can be painful and need to be removed with surgery.

Researchers aren’t sure what causes adenomas, but they suspect that fluctuations in hormones contribute to them. Some people seem to be more prone to breast adenomas and can even have several in each breast at the same time.

There are a few different types of breast adenomas:

A fibroadenoma is the most common type of breast adenoma. It tends to develop in women aged 15 to 35 and may be associated with taking birth control pills before age 20.  

Fibroadenomas can be round or oval and range from the size of a small marble to a golf ball. They may feel rubbery or hard, but don’t typically hurt and are easy to move around under the skin. Most fibroadenomas don’t increase your risk of breast cancer, but complex fibroadenomas (which have calcium deposits and cysts) may slightly increase your breast cancer risk. Most fibroadenomas go away on their own, but larger ones may be removed with surgery.

Tubular adenomas are found mostly in women younger than age 35. These rare adenomas often look and feel like fibroadenomas, but appear different when they are observed under a microscope. Emil Fernando, MD, a surgical oncologist and breast cancer expert with the ​​Allegheny Health Network, says he usually recommends surgery to remove a tubular adenoma just in case the growth has been misdiagnosed when it’s actually something more dangerous.

A nipple adenoma occurs within or under the nipple. It often causes nipple discharge and may cause bleeding. Nipple adenomas are more likely to be painful and require surgical removal than other types of breast adenomas, says Fernando. Usually the nipple itself does not need to be removed.

A lactating adenoma is the most common cause of a breast mass in a pregnant or breastfeeding woman. The growths are easy to move under the skin and typically contain multiple lobules, which are small glands that make milk. Lactating adenomas often disappear on their own once you give birth or stop breastfeeding, so they don’t usually need to be removed.

Pleomorphic adenomas are very rare in the breast but common in the salivary glands. They can be difficult to diagnose and are sometimes misdiagnosed as malignant tumors. Pleomorphic adenomas are referred to as “mixed” tumors because they don't just arise from the thin layer of tissue that lines surfaces inside the breast, but also an additional type of tissue. They mostly occur in postmenopausal women and around the areola. They are often surgically removed.

An apocrine adenoma is an extremely rare breast mass that is completely made up of apocrine cells, which make up a gland in the breast that adds fat droplets to breastmilk. They have edges that clearly separate them from the breast of the breast and may contain calcium buildup (called calcifications). There are so few cases of apocrine adenomas that researchers are unable to say if they increase breast cancer risk. They may require surgery.

Ductal adenoma is extremely rare but is most common in women older than age 60. It may appear similar to a malignant tumor, so surgery is recommended. It appears in the ducts that carry breastmilk to the nipples. You may be able to feel it as a lump, and it may cause nipple discharge. 

You may first notice a breast adenoma while bathing or while doing a self-exam. Alternatively, your doctor may notice it during a medical exam, or a mammogram may detect it. Depending on a few different factors, it may be diagnosed via ultrasound, mammogram, or biopsy. If you’re under age 30, your doctor will probably diagnose it with ultrasound. If you’re over 30, they will probably use a mammogram. If these tests don’t give a clear answer to what the breast lump is, your doctor may order a breast MRI, which can sometimes clarify the diagnosis, or may recommend a biopsy to be sure. 

If you’ve been diagnosed with a breast adenoma that your doctor is confident isn’t breast cancer, it doesn’t need to be treated. If the breast adenoma won’t stop growing, the diagnosis is unclear, or you’re experiencing pain or other discomfort, your doctor will likely recommend surgery. 

The surgery for a breast adenoma only takes about a half hour or so and is usually outpatient — this means you get to go home the same day as your surgery. Recovery takes about a week, Fernando says. The resulting scar is typically small and can be hidden around the areola or on the underside of the breast. 

No, they generally are not linked to a higher breast cancer risk.

In rare cases, cancerous tumors may be mistaken as adenomas, Fernando says. This is why if a breast tumor seems like an adenoma and isn’t surgically removed, providers monitor it to make sure that it doesn’t show signs of growth or other changes that may suggest a malignant tumor.