A breast biopsy is a test performed by taking a sample of breast tissue from an area deemed suspicious by a doctor after he or she examines the results of a woman's mammogram. A pathologist then analyzes the sample, and determines whether the tissue is cancerous by looking at the cells underneath a microscope, according to the American Cancer Society. The types of breast biopsies differ by procedure method.
Fine-Needle Aspiration Biopsy
The American Cancer Society reports that a fine-needle aspiration biopsy is a type of breast biopsy in which a very thin needle attached to a syringe is inserted into the breast. By pulling back on the syringe plunger, the doctor is able to aspirate the cells of the area of interest into the needle. The doctor may guide the position of the needle by feeling for the lump, or use ultrasound to image the lump if it cannot be felt. The doctor may also use mammograms taken from two angles to locate the breast lump, which is called a stereotactic needle biopsy. If the needle aspirates fluid, meaning that the lump is fluid-filled, the lump is most definitely not cancer. A fine-needle aspiration biopsy is a very quick and easy way to determine whether the lump is a fluid-filled cyst or a solid tumor.
Core Needle Biopsy
A core needle biopsy involves using a thin needle to remove a sample of breast tissue. However, the needle is slightly thicker than the one used for fine-needle aspiration biopsy, the Mayo Clinic notes. Often several samples of tissue are taken, usually about the size a grain of rice.
Vacuum-Assisted Core Biopsy
This type of biopsy, according to the American Cancer Society, is similar in principle to core needle biopsies, but removes larger amounts of tissue. One type of vacuum-assisted core biopsy uses a tool called the Mammotome. The procedure involves inserting a hollow probe into a small incision in the breast and suctioning a core of breast tissue into the probe, which is cut from the breast with a rotating knife located within the probe.
Surgical Biopsy
The sample of breast tissue in this type of biopsy is removed by making an incision in the skin, and physically removing the tissue. Harvard Health Publications, a service of the Harvard Medical School, reports that this is the most invasive type of biopsy, and will leave a visible scar. The procedure may even change the shape or size of the breast. A surgical biopsy in which only a part of the lump is removed for diagnostic purposes is called an incisional biopsy. When the entire lump is removed, the procedure is called an excisional biopsy.
If the lump cannot be felt, the doctor may use some of the imaging techniques described above, and insert a wire through a needle into the breast. The needle is removed, but the wire is left in place to mark the location of the suspicious lump during surgery.
