Content Map Terms

Breast Biopsy

Test Overview

A breast biopsy removes a sample of breast tissue that is looked at under a microscope to check for breast cancer. A breast biopsy is usually done to check a lump found during a breast examination or to look at a suspicious area found on a mammogram, an ultrasound, or an MRI.

There are several ways to do a breast biopsy. The type of biopsy that you have will depend on the size and location of the abnormal area.

Fine needle breast biopsy.

Your doctor inserts a thin needle into a lump or abnormal area and removes a sample of cells or fluid.

Core needle biopsy.

Your doctor makes a small cut in the skin and inserts a needle with a special tip to remove samples of breast tissue. Samples may be removed using a vacuum device. To guide the biopsy, ultrasound or other imaging may be used. After samples are removed, a tiny marker clip is usually placed at the biopsy site.

Open (surgical) biopsy.

Your doctor will make a cut in the breast to remove an area of breast tissue. An open biopsy may be done if the results of a needle biopsy were uncertain.

Why It Is Done

A breast biopsy checks to see if a breast lump or a suspicious area seen on a mammogram is cancerous (malignant) or non-cancerous (benign). Testing a biopsy sample is the only reliable way to find out if cancer cells are present.

How To Prepare

If you take a medicine that prevents blood clots, your doctor may tell you to stop taking it before your test. Or your doctor may tell you to keep taking it. (These medicines include aspirin and other blood thinners.) Make sure that you understand exactly what your doctor wants you to do.

You will be asked to sign a consent form that says you understand the risks of the test and agree to have it done.

If a breast biopsy is to be done under local anesthesia, you don't need to do anything else to prepare for the biopsy.

If the biopsy is to be done under general anesthesia, follow the instructions exactly about when to stop eating and drinking, or your surgery may be cancelled. If your doctor has told you to take your medicines on the day of surgery, do so using only a sip of water. Be sure you have someone to take you home. Anesthesia and pain medicine will make it unsafe for you to drive or get home on your own. Arrange for someone to drive you home if you will be having general anesthesia or are going to be given a sedative.

Other tests, such as blood tests, may be done before your breast biopsy.

How It Is Done

Before the biopsy

You will take off your clothing above the waist. A paper or cloth gown will cover your shoulders. The biopsy will be done while you sit or lie on an examination table. Your hands may be at your sides or raised above your head. (It depends on which position makes it easiest to find the lump.) Or you may lie on your stomach on a special table that has a hole for your breast to hang through. A mammogram, an ultrasound, or an MRI may be used to find the exact site for the biopsy.

Fine needle breast biopsy

Your doctor numbs your skin with a shot of numbing medicine where the biopsy needle will be inserted. When the area is numb, a needle is put through your skin into your breast tissue to take a sample. The needle is then removed. Pressure is put on the needle site to stop any bleeding. A bandage is put on.

Ultrasound may be used to guide the placement of the needle during the biopsy.

The biopsy sample is sent to a lab to be looked at under a microscope.

Core needle biopsy

Your doctor numbs your skin with a shot of numbing medicine where the biopsy needle will be inserted. When the area is numb, a small cut is made in your skin. A needle with a special tip is put into the breast tissue. The doctor takes some samples and usually inserts a clip to mark the biopsy site.

Pressure is put on the needle site to stop any bleeding. A bandage is put on.

Most core needle biopsies are done using imaging to find the exact area in the breast to sample. Types of image-guided core needle biopsies include:

  • Ultrasound-guided biopsy. An ultrasound probe guides placement of the needle or vacuum device.
  • Stereotactic-guided biopsy. X-ray images guide placement of the needle.
  • Tomosynthesis-guided biopsy. Digital breast tomosynthesis (DBT) uses 3D X-ray images to guide placement of the needle.
  • MRI-guided biopsy. A contrast agent may be used to see the abnormal area. MRI is used to guide the biopsy.

A core needle biopsy may also be done using a probe with a gentle vacuum to remove the samples.

Open biopsy

The biopsy may be done in a surgery clinic or the hospital.

Anesthesia will be used to keep you comfortable during your biopsy. You may have a local anesthesia, sedation, general anesthesia, or a combination of these. Depending on what kind of anesthesia you have, you may be asleep for your biopsy.

And then, after you are numb or asleep, your doctor makes a cut through the skin to remove part or all of the abnormal tissue. If a small wire was placed to mark the biopsy site, your doctor will take tissue from that area.

Stitches are used to close the skin, and a bandage is put on.

How long the test takes

  • A fine needle breast biopsy takes about 5 to 15 minutes.
  • A core needle biopsy may take 15 minutes to 60 minutes, depending on how the procedure is done.
  • An open biopsy takes about 60 minutes.

How It Feels

You will feel only a quick sting from the needle if you have a local anesthetic to numb the biopsy area. You may feel some pressure when the biopsy needle is put in.


The possible risks from a breast biopsy include:

  • An infection at the biopsy site. An infection can be treated with antibiotics.
  • Bleeding from the biopsy site.
  • Not getting a sample of the abnormal tissue.
  • Dizziness and fainting.

Core needle breast biopsies may leave a small round scar. Open biopsies leave a straight-line scar. The scar fades over time. A fine needle breast biopsy usually doesn't leave a scar.


Breast biopsy


No abnormal or cancer cells are present.


Breast changes that are not cancer (benign) include:

  • Calcium deposits in the breast.
  • Cysts, which are lumps filled with fluid.
  • Enlarged breast lobules (adenosis), which are small round lumps that sometimes can be felt.
  • Fat necrosis, which are round, firm lumps formed by damaged fatty tissue.
  • Fibrocystic lumps and firm tumours (fibroadenomas).

Breast changes that are not cancer but may increase your risk for cancer include:

  • Abnormal cells in the breast ducts (atypical ductal hyperplasia or ADH).
  • Abnormal cells in the breast lobules (atypical lobular hyperplasia or ALH).
  • Many abnormal cells in the breast lobules (lobular carcinoma in situ or LCIS).

Cancer cells are present.


Current as of: March 1, 2023

Author: Healthwise Staff
Medical Review:
Sarah Marshall MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Kathleen Romito MD - Family Medicine
Laura S. Dominici MD - General Surgery, Breast Surgical Oncology