A biopsy is a test that establishes the precise diagnosis when a breast lump or other abnormality is discovered. With this procedure, cells or tissue are removed and examined under a microscope by a specially trained doctor called a pathologist. Of the approximately half-million breast biopsies performed each year, as many as 80 percent turn out to be benign.
What Happens When a Lump is Found or an Abnormal Mammogram Report Occurs? (Diagnostic Alternatives)
Cyst Aspiration
Cyst aspiration uses a narrow-gauge needle attached to a hypodermic syringe to remove fluid from a "cyst," (a fluid-filled mass). The mass may be palpable and/or detected by mammography. If fluid appears, the growth is a cyst that will break down and disappear from the monitor. If the physician is unable to draw out any fluid, the growth is solid, making it necessary to perform a biopsy.
Fine Needle Aspiration Biopsy (FNAB)
Fine Needle Aspiration Biopsy (FNAB) uses a narrow-gauge needle, under vacuum pressure, (similar to or smaller than the type used to draw blood) attached to a hypodermic syringe to remove cells from a palpable mass or thickening for pathologic study. The gauge of the needle is based on the size of the patientís breast and the profile of the suspicious lump.
Needle Localization Biopsy
When non-palpable mammographic findings warrant biopsy to determine the presence or absence of malignancy, a needle localization biopsy can be performed. This mammographic procedure localizes the abnormality by placing a special needle or wire through the skin to guide the surgeon. An x-ray of the problem area is usually taken during surgery to ensure accurate tissue removal.
Stereotactic Biopsy
Another way to localize a nonpalpable lesion is by stereotactic guidance. This is most commonly used to biopsy microcalcifications or indiscriminate mammographic shadows. Stereotactic biopsy uses radiation to produce double-image (stereo views) mammography of the suspicious area. The two stereo images are viewed next to each other on the same film. Computer-generated coordinates are then created from the two images. The abnormal area is targeted and a needle is "shot" into the breast to remove a sample of tissue.
Core Needle Biopsy
Core needle biopsy uses a larger bore-cutting needle to withdraw a sample of tissue from a palpable or mammographically detected mass. The gauge of the needle is based on the size of the patientís breast and the profile of the suspicious lump.
Incisional Biopsy
An incisional biopsy surgically removes a portion of the lump for microscopic examination of tissue, after making an incision in the skin. This technique involves either a local or general anesthesia.
Excisional Biopsy
An excisional biopsy surgically removes (excises) the entire lump through a skin incision. This technique also involves either a local or general anesthesia.
Ultrasound-Guided Biopsy
Ultrasound-guided biopsies can be useful for patients with lesions that show up on only one view or that only show up in an ultrasound image, pregnant women or nursing mothers who need to avoid exposure to x-rays and patients with multiple lesions in one or both breasts. High-resolution ultrasound uses high-frequency sound waves, or echoes, to project the internal anatomy of the breast onto the screen of a monitor. A transducer, functioning like a microphone, is placed on the breast after a special gel has been applied to the skin. The transducer both sends and receives sound waves that produce the internal imaging of the breast.
1. Ultrasound-Guided Fine Needle Aspiration
The radiologist or sonographer performing the ultrasound can locate the growth with the help of a transducer to direct a fine gauge needle into the area of the growth. With the needle functioning under vacuum pressure, the physician is then able to drain away any fluid. If fluid appears, the growth is a cyst that will break down and disappear from the monitor. If the physician is unable to draw out any fluid, the growth is solid, making it necessary to perform a biopsy.
2. Ultrasound-Guided Fine Needle Aspiration Biopsy
An ultrasound-guided fine needle aspiration biopsy is like an ultrasound-guided fine needle aspiration (see above). A local anesthetic may be used to numb an area of skin on the breast. Once the physician locates the suspicious area, he can then guide a needle to the area with the use of the ultrasound equipment. Once the needle is in place, a vacuum is created within the syringe, cells are drawn into the needle. It is common for the doctor to make several insertions (passes) of the needle into the growth to make sure that an adequate sampling of cells is obtained.
3. Ultrasound-Guided Core Needle Biopsy
An ultrasound-guided fine needle aspiration biopsy is similar to an ultrasound-guided fine needle biopsy (see above). A transducer is placed on the patientís breast where it will receive and send the sound waves that will produce the internal breast image. A local anesthetic is used to numb the patientís breast(s), after which a 14 or 18 gauge core needle is injected. Due to the size of the needle, the physician will need to make a small incision (nick) in the skin to insert the wider core needle. The size of the needle is the main difference between a fine needle and core needle biopsy.
Future Techniques Currently Under Investigation
Ultrasound Computed Tomography (CT)
Ultrasound CT is currently being tested at The University of California, San Diego, California. It does not involve radiation to get inside the breast for cross-sectional pictures or image ěslicesî called tomograms. The images are projected onto a computer screen for viewing via ultrasound equipment. It takes about 20 minutes for a full screening that requires seven or eight images to get a complete picture of the breast. Researchers are hopeful that this technique will provide clinicians with better defined images of solid masses that are particularly difficult to identify in dense breasts.
Positron Emission Tomography (PET Scan)
In a PET scan tomogram, a patient receives an injection of a radioisotope that releases a nuclear substance (positron). Concentrations of the isotope are absorbed by breast cells that can form ěhot spotsî. A rapid film sequence creates image ěslicesî (tomograms) that, when put together, create a complete picture of the breast. A radiologist can then zero in on the ěhot spotsî to detect a small cancer growth and the spread of cancer to the lymph nodes. The PET scan also allows clinicians to get a good view of very dense breasts. False-positive results can occur because the images produced make it difficult to distinguish between infections and cancer.
