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 a suspicious area found on a mammogram or ultrasound. See an illustration of the female breast.

There are several ways to do a breast biopsy. The sample of breast tissue will be looked at under a microscope to check for cancer cells.

• A fine-needle aspiration biopsy puts a thin needle through the skin, into the lump, and removes cells to look at. Needle aspiration may be done to see if the lump is solid or fluid-filled (cyst). If the lump is a cyst, it will go away after the fluid is removed. If there is no fluid, another type of biopsy will be done.
• A core needle biopsy uses a large needle fitted with a special tip. The needle goes through the skin to the lump or area to take out a sample of tissue about the size of a pencil lead. A core needle biopsy can also be done using a suction unit that gently removes a larger sample of tissue.
• A stereotactic biopsy uses a special type of X-ray during a core needle biopsy to find the area of the breast where the biopsy sample will be taken. This technique can check a lump that cannot be felt on breast examination but is seen on mammogram or ultrasound. A small incision is then made in the skin of the breast, and the core needle is guided by the X-ray to the biopsy site to take a tissue sample. Stereotactic biopsy may not be appropriate for all types of breast lumps.
• An open biopsy makes a cut in the skin and removes a sample of the lump or the entire lump. If your doctor cannot feel a lump, a needle (or wire) can be put in the suspicious area during a mammogram done just before surgery. The needle (or wire) then guides your doctor to the suspicious area to take a biopsy sample.

More tests or biopsies may be needed if problems are found during the first biopsy or if your doctor is concerned about a certain area of your breast.

Why It Is Done

A breast biopsy checks to see if a breast lump is cancerous (malignant) or noncancerous (benign).

How To Prepare

Tell your doctor if you:

• Are taking any medicines.
• Are allergic to any medicines, including anesthetics.
• Are allergic to latex.
• Have any bleeding problems or take blood thinners, such as aspirin, heparin, warfarin (Coumadin), enoxaparin sodium (Lovenox), or clopidogrel bisulfate (Plavix).
• Are or might be pregnant.

You will be asked to sign a consent form. Talk to your doctor about any concerns you have regarding the need for the biopsy, its risks, how it will be done, or what the results will indicate. To help you understand the importance of the biopsy, fill out the medical test information form(What is a PDF document?).