Finding a Lump in Your Breast—7 Possible Causes

Changes in your breast tissue do not always indicate cancer. Here are seven reasons you may feel a lump.

If you feel a lump in your breast tissue, it is important to know what factors may be causing this change—as cancer may not always be the culprit. According to the American Cancer Society, when it comes to changes in the breast, benign (non-cancerous) conditions are more common than cancerous conditions.

Here are seven reasons why a lump may develop in the breast, and what to do if you suspect you may be experiencing one of these issues.

Doctor woman examining her patient breast for cancer

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Intraductal papillomas are non-cancerous tumors that develop in the breast—more specifically the milk ducts and other ducts located away from the nipple, according to the American Cancer Society. Papillomas are made up of various tissues and blood vessels that can cause a lump.

Papillomas may also cause a clear or bloody discharge from the nipple, typically from only one breast, according to the American Cancer Society.

Treatment for papilloma varies depending on the size and severity of symptoms, according to the American Cancer Society. If symptoms are severe or the papilloma is causing other issues, your healthcare provider may surgically remove it along with the part of the duct it grew in.

You may have a slight increased risk for developing breast cancer if you have more than one papilloma, according to the American Cancer Society. Just one papilloma does not increase the risk of cancer, unless there are other changes in the breast.

Your Period

You may experience changes in your breasts before and during your period, according to the National Cancer Institute. It is common to experience swollen, tender, or painful breasts at this time. This is because of extra fluid that accumulates in your breasts around the time of your period.

Try over-the-counter pain medication, and warm or cold compresses, and make sure your bras fit well to limit the discomfort, according to the National Cancer Institute.


Fibroadenomas are benign tumors of the breast, according to MedlinePlus. They're most common during puberty and pregnancy. Fibroadenomas are made up of breast gland tissue. They often feel firm and rubbery and are easily moveable under the skin. They're also usually painless.

Healthcare providers can often tell if a lump is a fibroadenoma from either an ultrasound or a mammogram, according to MedlinePlus. Fibroadenomas may be left in place or surgically removed—the latter of which usually happens when biopsy results are unclear or the lump grows larger.

Fibrocystic Breast Changes

Fibrocystic breast changes are when there are changes in the fibrous tissue in the breast and/or a cyst has developed, according to the American Cancer Society.

Fibrosis means you have extra connective tissue, that can feel rubbery or firm, in your breast. Cysts go hand-in-hand with fibrosis. Cysts are small sacs filled with fluid. They can become bigger if fluid continues to build up, according to the American Cancer Society. They are usually round, tender, and can move around your breast. Any changes in hormones, like during your period, can cause the pain to worsen and the cyst to increase in size.

Fibrocystic breast changes do not increase your risk for breast cancer, according to the American Cancer Society. However, if an ultrasound reveals a cyst contains both fluid and solid matter, or only solid matter, that is called a complex cyst. These growths need to be biopsied, as they may be cancerous.

Fat Necrosis

Necrosis is when fat tissue in the breast has died, typically due to an injury, surgery, or radiation, according to the American Cancer Society. When the cells die, the remaining pieces of the cells form into a sac of greasy fluid. This is called an oil cyst. Necrosis and oil cysts can cause a lump to form. Typically, they are painless but they are hard to the touch.

This kind of breast lump isn't cancer, but it can feel that way. "Sometimes it will feel like a rock-hard mass," said Therese Bevers, MD, medical director of the Cancer Prevention Center at the University of Texas MD Anderson Cancer Center in Houston. "This can be kind of scary."

Head to a healthcare provider to check it out—but if it is fat necrosis, you'll usually leave it alone. "It probably would create more problems if you take it out," Dr. Bevers said. "Surgery itself is trauma. The concern is you might create another lump."

Phyllodes Tumors

Phyllodes tumors are a rare type of lump that start in the connective tissue of the breasts, while other tumors tend to start in the duct or gland, according to the American Cancer Society.

"A phyllodes mass may be a little bit more lumpy and have multiple nodules," Dr. Bevers said. This type of tumor is common for people in their 40s, although the tumor can develop at any age, according to the American Cancer Society.

While most of these growths are benign and don't increase the risk of cancer, they do need to come out. "Phyllodes tumors will grow uncontrollably," Dr. Bevers said. One in four phyllodes tumors are cancerous, but they don't usually respond to radiation, chemotherapy, or hormonal breast cancer treatment, according to the American Cancer Society.

The treatment for phyllodes tumors is surgery. If the tumor is benign, a biopsy (surgical cut to remove a lump) will be done. However, if the tumor is cancerous this may involve a lumpectomy or mastectomy, where all or part of the breast is removed, according to the American Cancer Society.

Breast Cancer

Breast lumps are the most common symptom of breast cancer, according to the American Cancer Society. While these lumps are hard, they are usually painless. Breast cancer is diagnosed with a mammogram or x-ray of the breast.

According to the American Cancer Society, other symptoms of breast cancer include:

  • Swelling (around breast, armpit, or collarbone)
  • Nipple retraction
  • Nipple discharge
  • Nipple or breast redness
  • Nipple or breast dryness

Dr. Bevers said a type of cancer called invasive ductal carcinoma (IDC) often presents as a lump—"if [it's] large enough to be palpable," Dr. Bevers said.

If you do find a lump in your breast at any time—even following an annual wellness visit or mammogram—don't hesitate to let your healthcare provider know so they can decide any necessary next steps.

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