Based on studies of NAF cytology and breast cancer occurrence in studies involving over 20,000 women and spanning over 20 years, a five-category system has been established for reporting NAF cytology results.
The Text Table below provides the NAF Cytology Reporting System and the description of the findings associated with each category.
The following examples of each category are taken from the excellent article by Drs. Kerry AS Proctor, Leslie R Rowe, and Joel Bentz which was written for the clinical laboratory specialist (The role of nipple-aspirate fluid cytology in breast-cancer risk screening, March 2009, Medical Laboratory Observer). By designating this article as Open Access on Biomed Central, the authors have provided a great service to the medical community and we wish to thank them here.
Figure 1. NAF Category O. Negative for atypical or malignant cells. Rare benign (non-hyperplastic) ductal epithelial cell (arrow). Foam cells and proteinaceous debris noted in the background (arrow). The squamous epithelial cell (arrow) is a contaminate from the breast or nipple surface. ThinPrep-Pap stain.
Figure 2. NAF Category I. Benign normal ductal epithelial cells identified. Foam cells with small cluster of ductal epithelial cells. ThinPrep-Pap stain.
Figure 3. NAF Category II. Benign hyperplastic ductal epithelial cells identified. Note the slight nuclear enlargement and fine, smooth chromatin, which is evenly distributed. Nucleoli are sometimes present. Millipore Filter-Pap stain.
Figure 4. NAF Category III. Atypical ductal epithelial cells. The nuclear/cytoplasmic ratio is increased. The ductal cell nuclei are enlarged, with hyperchromatic nuclei. The chromatin is more coarse, but remains evenly distributed. The nuclear contours are slightly irregular. ThinPrep-Pap stain.
Figure 5. NAF Category III. Atypical hyperplasia. Atypical ductal epithelial cells in large cohesive fragment. Nuclear crowding and overlap, with atypical ductal cells. ThinPrep-Pap stain.
Figure 6. NAF Category IV. Suspicious for malignancy. Group of highly atypical ductal epithelial cells with dark, hyperchromatic chromatin. The chromatin is more irregular in its distribution, and coarsened. Note the nuclear contour pleomorphism is greater. There are prominent nucleoli. Millipore Filter-Pap stain.