Most lumps in the breast are benign (noncancerous), and they feel different than a cancerous breast lump does. Benign lumps usually feel smooth, soft, and move from side to side.1 With cancer, a breast lump typically feels hard like a rock and is immobile when you push on it. The lump may also be irregularly shaped.
During a breast self-exam (BSE), you may notice such lumps or differences in the texture and appearance of your breasts, but only 3% to 6% of these changes are due to breast cancer.2 It’s not cause for alarm, but still, it’s best to get a breast lump checked out.
This article explains the differences between noncancerous and cancerous breast lumps. It discusses imaging tests, like mammograms, ultrasound, and magnetic resonance imaging (MRI), and biopsy (tissue from the lump site) used to inform a healthcare provider’s diagnosis.
What Causes Non-Cancerous Breast Changes?
A lump in your breast may be a benign breast change that can occur due to hormonal fluctuations and age. Some people may experience a lump in the breast that comes and goes. Others may have cyclic breast changes, with a lump in the breast after their period that may need to be checked out.3
Although most lumps are not cancerous, they can be painful and lead to infections. Any changes in your breast should be reported to a healthcare provider.
A breast cyst is a benign, fluid-filled sac in the breast tissue. About 50% of women aged 30 and over develop breast cysts, also called fibrocystic disease. In some cases, these cysts can be painful and require aspiration (fluid removal) if the mass is large and is causing problems.2
Breast cysts are caused by hormonal imbalances such as increased estrogen levels and decreased progesterone. Sometimes breast cysts improve after menopause. Although usually benign, complex cysts do have a risk of becoming malignant (cancerous).2
Performing a monthly BSE isn’t the preferred screening for breast cancer; a mammogram is. But BSE does help you to become familiar with your breasts so you can report any changes to a healthcare provider quickly.
Breast fibroadenomas are benign tumors that consist of glandular and connective tissue. They typically affect women in their 20s and 30s, but they can occur at any age.4
A fibroadenoma typically feels round and firm and moves beneath the skin during a BSE. Fibroadenomas are often located near the surface of the breast. However, some may be too small to feel and are detected incidentally on a mammogram.
Although cancer risk is extremely rare with fibroadenomas, a biopsy may be warranted if the mass is large enough.4 Lumpectomy, radiofrequency ablation, and several other fibroadenoma treatments are available to remove the benign tumor.
Adenosis is a benign condition characterized by enlargement in the breast’s lobules. A breast lobule is a gland that makes milk. Adenosis can produce a lump that feels like a cyst or a tumor. In addition, it can have the appearance of calcifications on a mammogram. Calcifications can signify breast cancer, so a biopsy is required to diagnose adenosis.5
Mastitis is an infection of the breast experienced by many women who breastfeed. It is often accompanied by redness, swelling, and pain. In addition to home remedies, mastitis is treated with antibiotics.
Sometimes it may be difficult to distinguish between mastitis and inflammatory breast cancer since symptoms of both include breast redness, tenderness, and rash.6
Mammary duct ectasia is a benign condition in which the milk ducts become clogged and swollen, often causing a grayish discharge from the nipple. It may cause a small lump just under your nipple or cause the nipple to be retracted inward.7
It most commonly occurs around the age of menopause. Mammary duct ectasia usually resolves independently or can be treated with antibiotics.
Fat necrosis may occur when the breasts are damaged by surgery, radiotherapy, or trauma. Fat necrosis causes superficial (below the skin), hard, round lumps with skin retraction.
This condition mimics breast cancer on imaging tests and requires a biopsy for diagnosis. Seatbelt injuries, breast surgeries such as breast reduction, and taking blood thinner drugs are common causes of fat necrosis.8
Breast Oil Cysts
Breast oil cysts develop as a result of fat necrosis. As fat cells die, their contents are released, forming a cyst filled with oil. Although breast oil cysts usually resolve with time, they can be removed if they become uncomfortable.
Other Benign Lumps
Other benign lumps include breast hematomas, hemangiomas, adenomyoeptheliomas, and neurofibromas. Although these lumps are considered noncancerous, it’s important to continue monthly BSEs and report new breast changes to a healthcare provider.
According to a 2019 study in the International Journal of Cancer, women with benign breast disease (BBD) have an increased risk of developing breast cancer in the future. In addition, women with BBD, a family history of breast cancer, and genetic mutations have an even greater risk of developing breast cancer.9
Can Men Have Breast Lumps?
Men receive about 1% of all breast cancer diagnoses in the United States every year.10 They have breast lumps, too, most commonly under the nipple. Breast lumps in men are often more obvious (and easy to notice) because women have more breast tissue than men do.