Core Needle Biopsy

Medically Reviewed by Melinda Ratini, MS, DO on March 02, 2022

If your doctor notices something unusual during a regular breast exam or mammogram, they may suggest a core needle breast biopsy. A breast biopsy is a way to look at tissue from your breast to check for cancer.

Why the Test Is Done

Your doctor might suggest this test for several reasons:

  • You, or your doctor, feel a lump, thickening, or other change in your breast.
  • A mammogram shows an abnormal area in your breast.
  • An ultrasound or breast MRI shows something your doctor wants to check out.
  • You have changes in your nipple, like a discharge or puckered skin.

How It’s Done

You’ll usually get a core needle biopsy in a doctor’s office or clinic. You’re awake, but part of your breast is numb.

You may lie facedown on a table with openings for your breasts. Or you may lie flat, on your side, or sitting up. You will have to keep from moving during the test.

After numbing the area with a shot, your doctor will make a small cut -- about a quarter-inch -- in your breast. That’s where your doctor will insert a thin, hollow needle to remove samples of tissue.

During the test, your doctor will likely use an MRI, ultrasound, or mammogram to help guide the needle to the right spot. They’ll put the needle into your breast several times to collect different samples. Each is about the size of a grain of rice.

Usually, the doctor also places a tiny stainless steel clip inside the breast to mark the biopsy site. This will show up on mammograms and other tests to help them find the exact spot. It can help your doctor see if the area has changed and find it if you need treatment later. You won’t be able to feel or see the clip.

You should get a bandage and an ice pack, but no stitches, after the test.

After the Test

The doctor will probably tell you to take it easy for a day or so. But you should be able to do your normal activities after that.

You may have some bruising and tenderness in the area of the biopsy. If you noticed a lump in your breast before the biopsy, swelling might make it seem bigger than it is for a little while. It can take several weeks for bruising to go away.

To ease pain and swelling, apply a cold pack to the area. You may also want to take a non-aspirin pain reliever like acetaminophen.

Getting Results

The doctor will send your tissue samples to a lab for analysis. A doctor called a pathologist will study the samples under a microscope, looking for cancer cells. They’ll send their report to your doctor.

Ask your doctor when to expect results. It should be a few days to a week or so after the biopsy.

The report will show whether cancer was found and give details about the type. Just because your doctor suggests a biopsy, it doesn’t mean you have cancer. Most biopsies don’t find any signs of cancer.

Next Steps

If the biopsy does find cancer cells, the pathologist will do more tests to find out the type of cancer and how quickly it might grow. Using that information, you and your doctor will come up with a treatment plan.

If the test results aren’t clear, you might have another core needle biopsy or a different type of breast biopsy.

Show Sources


Mayo Clinic: “Breast Biopsy.” “Biopsy.”

American Cancer Society: “Core Needle Biopsy of the Breast.”

MD Anderson Cancer Center: “8 breast biopsy questions, answered.”

Agency for Healthcare Research and Quality: “Core-Needle Biopsy for Breast Abnormalities.”

National Breast Cancer Foundation: “Biopsy.”

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