FINE-NEEDLE ASPIRATION OF THE BREAST FOR DIAGNOSIS OF PREINVASIVE NEOPLASIA

Fine needle aspiration (FNA) of the breast is a well-tolerated procedu re used to evaluate palpable breast masses, has a reported mean specif icity of 99%, and a reported sensitivity of 70-99%. The false positive rate varies from 0-0.4% in most larger series, with a reported false negative rate ranging from 0.7-22%; however, higher false negative rat es have been reported in tumors under 2 cm in diameter. The FNA techni que uses a fine, 20 gauge or less, needle and is not associated with a significant risk of tumor growing out the needle tract.FNA cytology i s not effectively used if a breast mass cannot be palpated or distingu ished from fibrous tissue within the breast. The procedure can be appl ied to nonpalpable masses detected by mammography by employing stereot actic techniques. The cytologic samples obtained from FNA can be used to distinguish atypical ductal hyperplasia from in situ or invasive du ctal carcinoma; however, cytologic criteria to effectively distinguish ductal carcinoma in situ (DCIS) from invasive adenocarcinoma are not definitive in many cases, and are dependent on variables related to th e type of intraductal tumor, the size and character of the cell groups , and the presence of single or disaggregated tumor cells. Employing c urrent cytologic criteria, lobular carcinoma in situ (LCIS) may be dis tinguished from invasive lobular carcinoma in some cases; however, the individual LCIS cells are not morphologically distinct from lobular c arcinoma cells. Atypical lobular hyperplasia has cellular features ess entially the same as those seen in LCIS. Needle biopsy (NB) employs la rger needles of 14-16 gauge. Stereotactic guidance for NB can be augme nted with cytopathology by preceding the biopsy with FNA, and/or by co llecting the cellular sample available when washing the needle after t he tissue sample is removed. These needle biopsy washings are often hi ghly cellular and are complementary to the tissue diagnosis. FNA sampl es or NBs, if adequately cellular, are applicable for DNA analysis by static image analysis (flow cytometry). Flow cytometry is of limited p ractical value where cellularity or tumor representation is poor becau se morphologic confirmation cannot be established. These samples can a lso be used to calculate tumor proliferative fraction, employing Ki-67 antigen. Quantitation of nuclear organizer (AgNOR) regions and expres sion of HER-2/neu and p53 proteins can be accomplished in these sample s; estrogen and progesterone receptors can also be detected and quanti tated. (C) 1993 Wiley-Liss, Inc.