Breast cysts and solid lesions: the role of fine-needle aspiration.

Breast cyst aspiration and fine-needle or needle-core biopsy of palpable and nonpalpable breast masses can be cost-effective and in some situations provide instant resolution of cystic masses. The limitations of the techniques must be known if the benefits are to be exploited. New evaluations on cyst fluid demonstrating proteins (common to breast cancer) have been demonstrated, as well as assessment of electrolyte ratios in fluid. These may give additional information regarding cyst character and potential risks for breast cancer. Physicians involved in the treatment of breast disease must be aware of these advances as well as being clinically adept in fine-needle aspiration.