What are breast lumps?

This page was reviewed under our medical and editorial policy by

Daniel Liu, MD, Plastic and Reconstructive Surgeon.

This page was reviewed on February 4, 2022.

You might feel breast lumps while doing a breast self-exam, or they might be noticed by your doctor during an examination or mammogram. Normal breast tissue can sometimes feel lumpy, but at times, you may feel a firm bump, nodule or firm or hard feeling in your breast that seems a little different. Breast lumps often have an irregular shape and can be around the size of a pea, or larger. Most of the time, these lumps are not cancer, but it’s important to be aware of them and have them checked out.

Breast lumps may seem rather easy to identify, but many women have questions about them, like how to know the difference between a benign lump and a cyst (answer: only a doctor can), and when it's time to see a doctor if you've noticed a cyst. To answer those questions and more, this guide will cover:

If you've felt a breast lump and are interested in making an appointment for diagnostic testing at City of Hope, or if you've already been diagnosed with breast cancer and want a second opinion on your diagnosis and treatment plan, call us or chat online with a member of our team.

What causes breast lumps

There are several types of breast lumps: benign, precancerous and cancerous. While no lump can be officially diagnosed until it’s been examined through diagnostic tests, it can be helpful to know about each type.

Learn how to perform a breast self examination.


A benign lump, sometimes called a fibrocystic change, is non-cancerous. While it’s understandable to worry about breast cancer if you feel a lump, remember that most breast lumps aren’t cancer—only a small percentage of them turn out to be malignant. 

You may notice lumps that appear through different seasons of your life. Sometimes, women who are menstruating feel swollen, tender breasts before or during their periods or feel lumps are caused by excess fluid. Lumps may also occur when you’re pregnant or breastfeeding from a condition called mastitis that causes blocked milk ducts, and this may result in breasts that feel lumpy or tender. You may notice lumps or changes when taking hormonal medication, such as birth control pills, and later in life when approaching menopause. 


Cysts are another common cause of benign breast lumps. These are fluid-filled sacs that form when fluid builds up in the breast glands. They are common in premenopausal women and those taking menopausal hormone therapy. While they’re most often found in women in their 40s, they can occur at any age. 

They often feel like round lumps that are movable, although they may also be tender to the touch. Due to hormonal changes, you may find that a cyst gets larger and more painful right before your menstrual period begins. 

If you have a breast cyst, it may either be a microcyst or a macrocyst. Microcysts are smaller—they are generally too small to feel, so they're often found as a result of imaging tests. In contrast, macrocysts are larger, and you may be able to feel them. They can grow to around 1 to 2 inches in diameter.

Generally, cysts don’t need to be removed unless they’re causing discomfort. In that case, the cyst may be drained during a procedure using a long, hollow needle. 


Fibroadenomas are common in women in their 20s and 30s, although they can happen at any age. After menopause, they tend to shrink. These lumps tend to feel firm and rubbery and are made of glandular and connective tissue. They’re a type of benign breast tumor, and they sometimes feel like a marble in the breast. 

A fibroadenoma can be either simple or complex. Simple fibroadenomas tend to look identical to one another under a microscope, and their presence doesn’t increase the risk of breast cancer. If the fibroadenoma is complex, this means it has different features than the simple type. The complex types may slightly increase the risk of developing breast cancer in the future. 

Your doctor will recommend an appropriate course of treatment, if any is needed, for a benign lump. Depending on the type of lump, your doctor may recommend having the lump removed or having a cyst drained, since these procedures may reduce discomfort. Or, your doctor may monitor the lump over time, watching to see if it changes or grows.


A precancerous lump doesn’t currently show cancer but has abnormal cells that may become cancerous in the future. Atypical ductal hyperplasia or atypical lobular hyperplasia are precancerous conditions characterized by abnormal cells in the milk ducts or lobules of the breast. Another, lobular carcinoma in situ (LCIS), develops when the abnormal cells form in a breast lobule. LCIS may raise the risk for cancer in either breast in the future.


Sometimes, lumps in the breast may be caused by cancer cells. While you may feel anxious about a new lump, know that the only way to diagnose cancer is with a biopsy, so try not to assume the worst if you’ve noticed a lump or change to your breast. 

While not necessarily indicative of cancer, be aware of any of the following changes to your breasts:

  • A new lump felt in either breast or near an armpit
  • Irritated or dimpled skin on the breast
  • Painful lumps or breast tissue
  • A change to the shape or size of one or both breasts
  • Unexplained swelling or thickening of the breasts
  • Red or flaky skin on the nipples or breasts

Make an appointment with your doctor if you notice changes, lumps or symptoms related to your breasts. Your doctor may schedule a mammogram, an X-ray picture of the breasts that can indicate whether precancerous cells may be present. This diagnosis may then be confirmed by a biopsy, which removes cells from the suspicious area for testing. Treatment will depend on the results of these tests.

What to do if you find a breast lump

Finding a breast lump can cause concern, but most of the time, it won’t lead to a cancer diagnosis. In fact, there are several types of benign (noncancerous) breast changes that may make you feel a lump. 

A doctor can examine the lump and help you determine if any next steps are recommended.

Possible cause: Breast tissue changes

Breast tissue has natural lumps and bumps that you may feel, and you might just be more likely than others to develop lumps in your breasts. 

If you feel the same lumpiness in both breasts, or there isn’t one lump that’s firmer than the others, it’s most likely your normal breast tissue. That said, if you find a lump that feels harder, in only one breast, or one that just feels different than what you usually feel, address it with your doctor. 

Possible cause: Benign breast lumps

There can be several reasons (such as breast cysts or fibroadenoma) for breast lumps that aren’t related to cancer. 

A cyst is a pocket of fluid that can develop in the breasts. While these are usually too small to feel, sometimes they grow large enough to feel like a lump. Cysts don’t put a patient at an increased risk for cancer and don’t typically require any treatment. 

The most common benign tumor that feels hard but is mobile when you press on it is a fibroadenoma. In this case, your doctor may want to remove it, but having these don't lead to cancer for most patients (occurrence comes with a slightly increased risk). 

When to call your doctor

While in most cases a breast lump doesn’t signal cancer, it’s still important to see your doctor as soon as you can. They may ask you questions about your history, like whether anyone in your family has been diagnosed with cancer, and whether you’re having other symptoms.

Tests used to diagnose breast cancer

Your doctor will likely do a physical exam and may suggest some other diagnostic tests, if they can’t determine what the lump is from touch alone. Sometimes a biopsy is needed, along with certain imaging tests to make an accurate diagnosis. These are some of the most common tests used to determine whether a lump may be cancerous:

  • Breast biopsy: Biopsies are performed in several ways: taking a sample of breast tissue—or surgically removing the breast lump itself and testing it in a lab under a microscope. The type of biopsy recommended may depend on how concerned your doctor is about your cancer risk.
  • Mammogram: A mammogram (which is typically used for breast cancer screening) uses X-ray images of the breast from different angles to see more details of the lump.
  • Breast ultrasound: This type of imaging uses sound waves to tell if the lump is solid or fluid-filled. Tumors are solid, whereas breast cysts are a type of fluid-filled mass.
  • Breast MRI: An MRI (magnetic resonance imaging) test produces an image with radio waves and a magnet that is often used when more information is needed to make a diagnosis.

Learn more about how breast cancer is diagnosed.

Diagnosing and treating breast cancer at City of Hope

Finding a breast lump can be scary. That's why, when confirming whether a lump is cancer, many women choose to seek out a breast cancer expert who can provide answers with the sense of urgency and commitment to accuracy they deserve. 

Many patients come to City of Hope for a breast cancer diagnosis—and for second opinions—because of our expert, comprehensive cancer care. We only treat cancer at City of Hope, and our Breast Cancer Centers recognize the value in dedicating a multidisciplinary team of experts to a specific cancer type, especially one as complex as breast cancer.

At the Breast Cancer Centers at each of our City of Hope hospitals, located across the nation, our cancer experts are devoted to a single mission—treating breast cancer patients with compassion and precision. Each patient’s care team is led by a medical oncologist and coordinated by a registered oncology nurse, who helps track the various appointments, follow up on tests and answer questions that come up along the way. Your care team also may include a breast surgeon, radiation oncologist, radiologist, pathologist and a plastic and reconstructive surgeon with advanced training in helping patients restore function and appearance. Fertility preservation and genetic testing are also available for qualifying patients who need them.

Our pathologists and oncologists are experienced and trained in tools designed to diagnose, stage and treat different types of breast cancer, from early-stage ductal carcinoma in situ to complex diseases such as triple-negative and inflammatory breast cancer. 

If test results indicate your lump is cancerous, seeking a diagnosis at a center that specializes in breast cancer is more likely to allow your oncologists to develop a treatment plan more quickly than had you gone to a general hospital that may require further follow-up appointments. We also provide our services under one roof, which means if you end up treating with us, you’ll see your providers (breast surgeon, radiologist, supportive care providers, etc.) in one building, and you may be able to receive your diagnosis and, if the results indicate cancer, review your personalized treatment plan within a couple of days.

Our breast surgeons offer microsurgical approaches such as nipple-sparing mastectomy and reconstructive flap surgery, and our radiation oncologists employ technologies designed to reduce the risk of radiation exposure to the heart and other critical organs. The Breast Cancer Center is also involved in clinical trials on precision treatments and innovative technologies, including targeted therapies. These trials may offer participants options that may have otherwise been unavailable to them.

As part of our patient-centered care model, your multidisciplinary care team may recommend various evidence-informed supportive therapies, such as naturopathic support, psychosocial support, nutritional support, physical and occupational therapy and pain management, to help you manage side effects such as fatigue, hair loss, nausea and/or loss of appetite. Addressing these issues early and vigilantly may help you maintain your strength, stamina and resilience, so you’re better able to reduce the risk of treatment delays.. The entire team works together with a whole-person focus, which is at the heart of our centers’ dedication to personalized, comprehensive care.

No matter where you decide to go to assess your breast lump, while researching your options, look for a facility and a care team with the expertise you need and the credentials you trust.

If you've felt a breast lump and are interested in making an appointment for diagnostic testing at City of Hope, or if you've already been diagnosed with breast cancer and want a second opinion on your diagnosis and treatment plan, call us or chat online with a member of our team.

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