What Is a Breast Biopsy?

What to expect when undergoing this test

A breast biopsy is a procedure in which a sample of breast tissue is obtained surgically so it can be tested for breast cancer. A needle biopsy or an open procedure can be used to obtain the sample. Overall, 70 to 80% of biopsies are found to be negative for cancer, but some can show signs of benign breast diseases or conditions that predispose you to breast cancer.

3 types of breast biopsies

Verywell / Cindy Chung

Purpose of Test

A breast biopsy may be recommended if a person develops symptoms of breast cancer, or if an abnormality is found on a screening test, such as a mammogram, or on follow-up tests such as breast ultrasound or breast MRI.

A breast biopsy can be done for men or women because men can also develop breast cancer.

Symptoms of breast cancer can include:

  • A breast lump
  • Breast dimpling
  • An orange peel appearance to the breast
  • Skin thickening on the breast
  • Nipple changes, such as a retracted nipple
  • Nipple discharge
  • A red rash or sores on the breast
  • Enlarging veins on the breast
  • A change in size, shape, or weight of a breast
  • An enlarged lymph node in the armpit

Findings on imaging tests that may suggest the need for a biopsy include:

  • The presence of microcalcifications or a spindle-shaped mass on mammogram
  • A solid or partly solid lump on breast ultrasound
  • A mass with irregular borders on a breast MRI

Women who have a high risk of developing breast cancer, such as those who have a strong family history or gene mutations linked with breast cancer, are often screened with a combination of MRI and mammogram. According to a 2018 study published In JAMA Internal Medicine, more biopsies are performed due to MRI screenings than mammogram screenings, but these biopsies are less likely to be positive for breast cancer.

Much less commonly, a breast biopsy may be done when a person is first diagnosed with breast cancer because of metastases to another region of the body (such as the bones, liver, lungs, or brain).

While an exam or imaging tests may suggest that breast cancer is present, a biopsy is ultimately needed to make the diagnosis and to determine the type of cancer and other characteristics.

Types of Breast Biopsy

Based on your symptoms and preliminary tests, your healthcare provider will determine which type of biopsy is most appropriate for you.

A breast biopsy may be done in one of several ways:

  • Fine needle aspiration: This involves the insertion of a thin needle through the skin to collect a sample of cells, usually if a lump is palpable (can be felt through the skin). It is particularly helpful in distinguishing fluid-filled cysts from solid masses.
  • Core needle biopsy: A core of tissue is collected with a large needle, often with ultrasound or MRI for guidance.
  • Open (surgical) biopsy: An open biopsy may be incisional (involving the removal of part of the abnormality) or excisional (removing all of the abnormality, as well as a margin of normal tissue). Ultrasound guidance, MRI guidance, stereotactic placement, or wire localization may be needed to locate the abnormality.

A skin biopsy or nipple biopsy may also be done if inflammatory breast cancer or Paget's disease of the nipple is suspected.


With a fine needle biopsy, if the cells are malignant (cancerous), it is not usually possible to determine the tumor grade (aggressiveness), whether the cancer is in situ or invasive, or whether receptors (such as estrogen receptors) are positive or negative.

If the results of a fine needle aspiration or core needle biopsy are unclear, or if cancer can't be ruled out, an open biopsy is usually recommended.

All types of breast biopsies carry the risk of false positives and false negatives.

  • False negatives occur when a cancer is present but the biopsy fails to detect it. It is more common with fine needle aspiration and least common with an open surgical biopsy. False negatives are more common when a breast mass cannot be felt on exam.
  • False-positive results occur when a biopsy suggests cancer is present when it is actually not. In a 2015 study published in JAMA, false-positive findings were noted on 17% of breast biopsies. False-positive diagnoses were less likely to occur with invasive cancer and more commonly seen with ductal carcinoma in situ (DCIS) and atypical hyperplasia.

Risks and Contraindications

As with any medical procedure, biopsies carry potential risks and reasons why the procedure should not be done.

Potential Risks

Bleeding and infection are potential risks of any type of breast biopsy. Additionally, there are risks associated with local and general anesthesia.

There is also a very small risk of the needle used for a fine needle or core biopsy penetrating the lungs and causing a pneumothorax (collapse of a lung). This is more common when the biopsy site is very deep in the breast.

Core needle biopsy poses a small risk of seeding tumor cells along the track of the needle, increasing the risk of metastases. While a 2009 review of 15 studies did not find any difference in survival in women who had this procedure as opposed to another form of breast biopsy, a 2017 study found that a core needle biopsy was associated with a higher rate of distant metastases five to 15 years after diagnosis, relative to people who had a fine needle aspiration biopsy.

Surgical biopsies can lead to scarring or disfigurement of the breast, especially when large amounts of tissue are removed.


Considerations that may rule out a breast biopsy include:

  • In women who are breastfeeding, there is a risk of a milk fistula.
  • In women with silicone breast implants, a core needle biopsy may not be advisable.
  • Using vacuum assistance with a core needle biopsy may be ineffective if the lesion is near the chest wall.
  • The tables used for stereotactic biopsies often have a weight limit of 300 pounds.
  • Stereotactic localization involves radiation, and benefits and risks need to be weighed carefully in pregnant women.

Before the Test

Your healthcare provider will discuss with you the indication for your procedure and the potential risks. They will ask you about any previous procedures you have had done on your breast, as well as any health conditions you have.

Your practitioner will review your risk factors for breast cancer, including your menstrual history, the number of pregnancies you've had, and any family history of breast cancer or other cancers.


The amount of time required for a breast biopsy procedure depends on the type you will be having. A needle biopsy may take five to 10 minutes. A core biopsy may take 15 to 30 minutes but may require more time if ultrasound or MRI guidance is needed.

You should set aside several hours for an open biopsy procedure, which can involve preparation and recovery time. If wire localization or a stereotactic procedure is done, this can take up to an hour or more of additional time.


A needle biopsy or core biopsy may be done in a clinic, although these procedures are usually done in a radiology department if ultrasound guidance is needed. For an open surgical biopsy, the procedure is usually done in an outpatient surgery center or as an outpatient procedure at a hospital.

What to Wear

You will be asked to remove your clothing and change into a gown before your biopsy procedure (usually just from the waist up for a needle or core biopsy). Afterward, plan to wear a supportive, but not tight, bra for up to a week.

Food and Drink

Usually, there are no dietary restrictions for a needle or core biopsy. Before a surgical biopsy, you will likely be asked to avoid eating or drinking anything after midnight the day before the procedure.


You should talk to your healthcare provider about any medications you take prior to the procedure. Often, it's recommended that blood thinners, aspirin, and anti-inflammatory medications like Advil (ibuprofen), be stopped for a few days before the procedure to reduce the risk of bleeding. This should only be done after discussing the risks with the healthcare provider who prescribes these drugs.

Keep in mind that some vitamins and dietary supplements may also increase the risk of bleeding and may need to be stopped a week or longer before your biopsy.


If you smoke, quitting before your biopsy reduces the risk of infection and improves wound healing. Refraining from smoking for even a day or two prior to your procedure may have benefits.

Quitting smoking is important not only for your biopsy. A few large studies including the 2017 Generations Study suggest that smoking is a significant risk factor for breast cancer.

Cost and Health Insurance

Most private insurers, as well as Medicare, cover the cost of a breast biopsy when indicated. With some insurance companies, or when special techniques are recommended, you may need to obtain prior authorization.

What to Bring

You should bring your insurance card with you on the day of your procedure, and you may be asked to bring any imaging tests or prior biopsy reports with you. Most often, you will be asked to bring the actual films or a CD of imaging tests such as mammograms, rather than the written report.

It's always a good idea to bring a book, magazine, or another item to entertain yourself in case your appointment is delayed.

Other Considerations

If you'll be having a surgical biopsy, you'll need to bring a companion with you who can drive you home. Even if the biopsy is done under local or regional anesthesia, rather than general, the medications you receive to relax you can interfere with driving.

During the Test

A nurse, your surgeon, and your anesthesiologist will talk to you before your procedure. Your nurse and anesthesiologist will check your vital signs and your surgeon will examine your lump if you have one. You will have time to ask any questions about your procedure as well.


You will be asked to sign an informed consent form indicating that you understand the purpose of the procedure and any potential risks and to change out of your clothes.

Your nurse will place an IV and attach monitors that will record your heartbeat and the oxygen level in your blood.

Throughout the Test

The breast biopsy procedure will vary depending on the type of biopsy you are having.

If you are having a stereotactic breast biopsy procedure, you will lie on your stomach with your breast hanging through a special hole in the table. Digital mammogram images are taken from different angles to create a 3-dimensional view of the breast. When the precise location of the lesion is defined, a needle biopsy may then be done, or the area is marked with a wire for an open biopsy.

Fine Needle Biopsy (FNA)

Before a fine needle aspiration, your skin will be cleansed with a disinfectant and a long narrow needle placed into the growth. A syringe is attached to provide suction. If fluid is present, such as with a cyst, it will be withdrawn; with a simple cyst, the procedure may make the lump disappear completely. If the lump is solid, a collection of cells will be collected.

Once the sample is obtained, the syringe is removed and the area is covered.

Core Needle Biopsy

Before a core needle biopsy, the skin is disinfected and local pain medication is injected. A small cut is then made in the skin and a needle is inserted through the skin and into the mass. This is often done with imaging guidance, even if a lump can be palpated. You may feel some pressure or a tugging feeling while the needle enters your breast.

When the healthcare provider is certain the needle is in the correct area, a spring-loaded instrument is used to obtain a grain-sized sample of tissue. Often, four to eight core samples are taken.

After the sample is collected, a clip is often placed in the region of the biopsy so that it can be identified during a future mammogram or surgery. (This clip will not be a problem if an MRI is needed.) Once the clip is placed, the needle is removed and pressure is placed on the wound for several seconds before the surgical dressing is applied.

A vacuum-assisted core biopsy is an alternative procedure in which a vacuum is attached to the hollow needle; it is used to obtain a larger sample of tissue than a typical core biopsy.

Surgical (Open) Biopsy

In the operating suite, you will be asked to lie on your back, and a curtain may be placed between your head and the surgical field. The procedure may be done with either a general anesthetic or with sedation followed by a local anesthetic.

Your breast will be cleansed with a disinfectant and surgical drapes placed to keep the field sterile. If you will be awake, a local anesthetic will be injected into the skin, and then deeper into your breast. You will feel a pinch when the needle penetrates your skin and may feel an ache in your breast as more anesthetic is injected. With a general anesthetic, you will be asleep throughout the procedure.

After you're asleep or when your breast is numb, the surgeon will make an incision. If you're awake, you may feel pressure and a tugging sensation as the tissue is removed.

When the procedure is done, the incision will be closed with sutures and surgical dressings will be applied.


The sample(s) collected are sent to a pathologist for review after your test is complete.

With a needle or core biopsy, pressure will be placed over the biopsy puncture site (where the needle was inserted). You will be watched for a short while and be able to return home as soon as you are feeling comfortable.

With a surgical biopsy, you'll be observed in the recovery room until you're awake. You may be given crackers and juice. When you're fully awake and comfortable, your monitors will be removed and you may return home.

After the Test

With a needle or core biopsy, you will be asked to keep the puncture site clean and dry, and you may be advised to remove the dressing in a day or two. Some bruising and aching are normal, and your healthcare provider may recommend that you sleep in your bra to keep pressure on the site for a few days. It's best to avoid strenuous activity for the first several days.

With an open biopsy, you may be asked to leave your surgical dressings in place until you follow up with your practitioner. Some healthcare providers advise wearing a bra around the clock to provide compression and reduce bruising.

During this time, you should avoid bathing or showering, but you may give yourself a sponge bath and wash your hair in the sink or tub. The arm on the side of your biopsy may be sore, and you may need help with some of your day-to-day activities.

Managing Side Effects

Usually, there are few, if any, symptoms after a fine-needle aspiration. You can have mild symptoms after a core biopsy, and your recovery can take longer after an open biopsy.

You may have swelling and discomfort for a few days, depending on the size of your biopsy. Ice packs may help, and some clinics may provide ice packs that can be placed in your bra. You may be advised to use Tylenol (acetaminophen) to ease the pain.

It's important to call your healthcare provider if you have a fever or chills, notice bleeding, redness, swelling, or discharge around the needle or incision site, or if you just don't feel well.

Interpreting Results

Your healthcare provider may call you or ask that you return to the clinic to discuss your results. You might receive a preliminary report at the time of the biopsy, but the final pathology report takes a few days to complete.

Biopsy results are defined as negative, positive, or inconclusive; in the case of the latter, another biopsy or other studies may be needed.

Findings may be listed on the report as:

  • Normal
  • Benign (noncancerous) breast conditions
  • Benign breast conditions that increase the risk of cancer
  • Carcinoma in situ
  • Cancer


A negative result means that there is no evidence of cancer or benign breast conditions.

Benign (Noncancerous) Breast Conditions

Many different benign breast conditions can be found on a biopsy, many of which are not associated with an increased risk of breast cancer.

Some of these include:

Benign Breast Conditions That Increase Breast Cancer Risk

Some benign breast conditions are associated with an increased risk of developing breast cancer in the future.

Some of these conditions include:

  • Atypical hyperplasia: Atypical hyperplasia is considered a precancerous condition. For example, roughly 40% of people with lobular hyperplasia will develop invasive cancer within 15 years of diagnosis.
  • Radial scar: Having a radial scar increases the risk of developing breast cancer.
  • Adenosis: Breast adenosis is a benign condition, but those who have adenosis are about 2 times more likely to develop breast cancer.

Carcinoma In Situ

Carcinoma in situ refers to abnormal cells that appear identical to breast cancer, but have not extended beyond the basement membrane. Since they have not extended past this region, they are considered non-invasive, and removal of the cluster of abnormal cells is expected to be curative. The two types of carcinoma in situ are:

Areas of carcinoma in situ can also exist along with invasive cancer.

Breast Cancer

Overall, between 20 and 30% of breast biopsies are positive for cancer. If your biopsy reveals cancer, your report will describe the tumor in a number of ways (with the exception of a fine needle biopsy).

The type of breast cancer will be listed and may include:

  • Ductal carcinoma: Cancers that arise in the milk ducts, ductal carcinomas are the most common type of breast cancer.
  • Lobular carcinoma: This arises in the lobules of the breast and is the second most common form of breast cancer.
  • Inflammatory breast cancer
  • Uncommon forms of breast cancer, such as medullary carcinoma, tubular carcinoma, mucinous carcinoma, and others

The tumor grade is a description of how abnormal the tumor cells are, with more abnormal cells consistent with more aggressive tumors. It is designated with a number between 1 and 3, with 1 being used for the least aggressive cancers and 3 being used for the most aggressive.

Special tests that are done to determine the hormone receptor status (whether the tumor is estrogen and/or progesterone receptor-positive) and HER2 status (whether the cancer is HER2 positive)—these are listed as either positive or negative.

If you have a surgical (open) biopsy, your pathology report will also comment about the tumor margins—the edges of the sample that was removed.

  • With negative margins, all of the tumor cells are found well within the surgery specimen (the tumor was completely removed).
  • With close surgical margins, the tumor is found completely within the biopsy sample, but extends to within 1 to 3 millimeters of the edge.
  • With positive margins, there is evidence that tumor exists all the way to the edge of the biopsy sample, and it's likely that some of the tumor was left behind in the breast.

A biopsy cannot determine if breast cancer has spread to lymph nodes or distant regions of the body, and therefore cannot tell you the stage of cancer.


The follow-up after your breast biopsy will vary depending on the results. Your healthcare provider might discuss genetic testing with you if you have a strong family history of breast cancer—whether your biopsy is positive or negative.

If your biopsy is negative, your practitioner will talk to you about the next steps. If the likelihood of cancer is low and the result is negative, it may be advised that you follow up with routine breast screenings. These tests are designed for people who have an average risk of breast cancer, so it's important to talk to your healthcare provider about the next steps that are recommended for your specific situation.

Breast Cancer Healthcare Provider Discussion Guide

Get our printable guide for your next healthcare provider's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

Even if your biopsy is negative, your healthcare provider may recommend a repeat biopsy or other testing if they believe that cancer may have been missed.

If you have a benign breast condition, follow-up is usually similar to those who have negative results. With benign conditions that increase breast cancer risk, the next steps will depend on your expected risk. For those who have atypical hyperplasia, medications such as Tamoxifen may be recommended. Follow-up, often with screening MRIs, may be recommended.

Carcinoma in situ is often treated with surgery similar to breast cancer, and sometimes with hormone therapy, although chemotherapy is not recommended.

If your biopsy indicates cancer, the first decision is usually to choose between a lumpectomy and mastectomy (unless you had a wide excisional biopsy with clear margins). Surgery shouldn't be delayed, but some people consider a second opinion before making this decision. Further treatments will depend on the stage of cancer and may include chemotherapy, radiation therapy, hormonal therapy, and/or HER2-targeted therapy.

A Word From Verywell

Breast cancer is not uncommon, and most people know of someone who has had to cope with the disease. It's important to understand that a breast biopsy is more likely to reveal benign changes than cancer. Even if cancer is found, the majority of them will be early-stage tumors. The treatment of these cases has improved, with newer options significantly reducing the risk of recurrence and often being minimally invasive. Even with metastatic breast cancer, treatments are improving and life expectancy is increasing.

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