Needle aspiration biopsy uses a needle that is attached to a syringe for collection of (by drawing up via suction; i.e., aspiration of) fluid, cells, or tissue directly from the mass. Usually, the doctor can perform this procedure while feeling the lump to help guide the needle. If a mass was seen on a mammogram, but the lump cannot be felt easily, the doctor may use ultransography (i.e., ultrasound examination), computed tomography scanning (a CT scan), or computer-guided imaging to help locate the mass and guide the position of the needle. Use of computer-guided imaging to locate the mass and help guide the position of the needle is called stereotactic needle biopsy.
If this procedure locates fluid, it is an indication that the lump is a cyst. If the procedure locates a solid mass, a biopsy sample of the mass will be removed and sent to a laboratory for further analysis under the microscope. Solid masses can be malignant.
Using needle aspiration, mammography, and a clinical breast exam, a doctor can determine with about 98% accuracy whether a lump is benign or malignant. If, however, there is still doubt, a core needle biopsy may be ordered.
Core needle biopsy uses a larger needle to remove a small cylinder of tissue from the lump. Then the specimen of tissue is sent to a laboratory for analysis under the microscope.