Having a breast biopsy under mammogram guidance

This biopsy is also known as a tomosynthesis guided or stereotactic guided breast biopsy.
It uses mammography imaging and low-dose X-rays to help find breast abnormalities and remove tissue samples for examination under a microscope.
It is less major than a surgical biopsy, which is done in an operating theatre while you are asleep.
It usually leaves little or no scarring and can be a good way to check calcium deposits or small lumps that can�t be seen on an ultrasound scan.

You will be asked to take off your clothes from the waist up and sit/lie down on a chair in front of the mammography machine.
The Mammographer will position your breast.
It will be held in place by the mammography paddle (a flat plate) on the mammography machine.
The skin over the area of the biopsy will be cleaned with a sterilising solution. A local anaesthetic will be injected into the skin to numb the area.
A biopsy needle with a small suction is then used. The consultant radiologist uses the mammograms to find the right area.
You will hear a whirring noise as each sample is taken.
Several samples will be taken. Pictures of the samples will also be taken.
At the end of the procedure, the radiographic assistant will press firmly on the area for up to 15 minutes. This helps to reduce bruising.
Paper strips are then placed over the puncture site and a dressing placed over the area.
You will be given an after-care leaflet to take home.

A tiny titanium clip is placed into the breast at the end of the procedure.
This is helpful if the area biopsied needs to be located again.
You will not be able to feel the clip and you can still have MRI scans.
After a couple of final mammograms to check the clip is in the right place, you will be allowed to go home.

Please call the Imaging Help Desk on 020 7288 5888 (Monday to Friday, 9am to 3pm) and ask to speak to the Breast Imaging Team before your appointment if any of the following applies to you:
- If you take any medicine that thins your blood and makes you bleed more easily. These include, Warfarin, Rivaroxaban, Apixaban, Clopidogrel (Plavix), or Heparin injections.
- If you have a medical condition which makes it difficult for your blood to clot normally. We may need to change your medication dose or test your blood before the biopsy is done.
- If you have a physical disability or find climbing steps difficult.
- If you are or think you might be pregnant.
You may eat and drink normally.
Do not put on deodorant, powder or creams on your breasts or underarm area within two hours of your procedure, as these products can affect your results.
Please tell the staff if you have any allergies.
We recommend that you do not drive yourself to the appointment.

A small part of your breast will be gently pressed during the whole procedure.
This may be a little uncomfortable at first.
The local anaesthetic used to numb the breast may sting for a few seconds before it takes effect.
More local anaesthetic can be given during the procedure if any discomfort is felt.
Most patients report the procedure is a little uncomfortable, but not painful.
Some women find it more comfortable to wear a bra after the procedure.
If you do not normally wear a bra, please bring a soft, non-wired bra (such as a sports bra) with you to wear after the biopsy, and for the following few days.

You may feel pain or discomfort after the local anaesthetic has worn off usually after 1-2 hours.
Taking simple pain killers such as paracetamol (not aspirin) can help with this or wearing a soft bra.

Bruising can cause swelling and the lump can appear to get bigger, but this usually settles by itself.
Sometimes a solid lump will form beneath the skin.
This is due to blood collecting and hardening within the breast.
It is called a haematoma.
If this happens, we recommend that you show it to your breast surgeon at your results appointment in clinic.

If the puncture site starts to ooze, apply some direct pressure for a minimum of 10 minutes until it stops.
If the bleeding does not stop or your breast starts to swell, take off the dressing.
Then press on the area again using an ice pack or a bag of frozen peas wrapped in a towel.
If after 30 minutes the bleeding still hasn�t stopped then please visit your hospitals Accident & Emergency department and take this leaflet with you.

There is also a small risk that the abnormal area is in a part of the breast where it is hard to take good samples of tissue.
This may mean the biopsy does not give a clear result.
Your Doctor may then suggest another test, such as a surgical biopsy to remove and check the area.

The tissue samples will be sent to the laboratory to be examined by a Pathologist.
Your results are also talked about in a weekly team meeting. This helps make sure you get the right care and treatment.
The results can take up to two weeks to be available.
An appointment will be made with your clinical team in the Breast Clinic.

Tel.: 020 7288 5888, Monday to Friday 9am to 3pm.

Published:

08 Jun 2026

Review:

06 Jun 2028

Reference:

ACW/Imag/HBBUMG/01