The role of liquid-based cytology in the investigation of breast lesions using fine-needle aspiration: A cytohistopathological evaluation

Introduction: Liquid-based cytology processing of breast fine-needle aspiration (FNA) specimens has been used in our institution since 1999. The aim of this study was to investigate the role of liquid-based cytology (Thin-Prep®) in the evaluation of breast FNA specimens. Patients and Methods: This study was carried out on 352 cases corresponding to equal number of women (134 malignant and 218 benign) examined from September 1999 to June 2003. A direct to vial study was planned. Aspirated material was directly immersed to cytolytR vial (Cytyc Corporation, Boxborough, MA). The specimens were transported to the laboratory non-refrigerated within 24 hr. Thin-Prep slides were made using the Thin-Prep 2000 processor. The remaining material was embedded in paraffin. Results: Altogether, 352 cases were examined and unsatisfactory smears were observed in 14 (3.9 %) out of all cases. The histologic examination verified that 128 out of 131 total malignant cases and 203 out of 207 total benign cases were correctly diagnosed with the cytological technique. False positives were found in four cases and false negative in three cases. Liquid-based technique presented a sensitivity of 97.7%, a specificity of 98%, a positive predictive value (PPV) of 96.9%, a PNV of 98.5%, and an over all accuracy (OA) of 97.9%. Conclusions: The processing of FNA breast specimens using liquid-based cytology offers an accurate diagnostic tool. Liquid-based cytology could reduce the uncertainty based in the cytological evaluation of FNA, because it offers the possibility to embed material in paraffin and take tissue sections with histological appearance identical to those observed in routine histological sections. Moreover it offers the potential advantage of retraining extra material for the purpose of ploidy analysis and immunohistochemical study in order to offer information concerning the expression of prognostic markers such as p53, MIB-1, steroid hormone receptors, and EGFR.