The spectrum of cytologic features in nonproliferative breast lesions

BACKGROUND. The reliability of cytologic criteria to classify nonproliferat ive breast lesions (NPBL) is still debated. Sampling error and heterogeneit y of breast lesions complicates the histologic correlation of fine-needle a spiration results further. METHODS. To provide optimal cytohistologic correlation, two smears (one tha t was stained with hematoxylin and eosin and one that was stained with Diff -Quik [American Scientific Products, McGraw Park, IL]) were prepared from s pecific tissue sections from breast biopsies without mass lesions. The 42 c ases classified as NPBL histologically were included in the current study. The cytologic features of the smears were evaluated. RESULTS. Cellularity ranged from low (40% of cases) to moderate (50% of cas es) to high (7% of cases). The cells were arranged in small clusters in 79% of cases, were mixed with large sheets in 17% of cases, and were in large sheets in 2% of cases. Intact lobules were noted in 31%. The configuration of the epithelial groups was complex in 62% of cases. Myoepithelial cells i n the background and within the epithelial groups were noted in all the spe cimens. The percentage of single epithelial cells was < 10 in 38% of cases, 10-20 in 41%, and 20-30 in 19%. Mild nuclear enlargement and overlap, micr onucleoli, and mild chromatin clumping were noted in a significant number o f cases. CONCLUSIONS. NPBL have been found to have a wide spectrum of cytologic appe arances. At one end of the spectrum, smears are cellular with up to 30% sin gle cells and large sheets in a complex configuration and exhibit nuclear e nlargement and overlap and prominent nucleoli, features that overlap with t hose described in proliferative breast lesions. Cancer (Cancer Cytopathol) 2001;93:140-145. (C) 2001 American Cancer Society.