Role of Ancillary Tests in Breast Fine Needle Aspiration Biopsy Cytopathology

Abstract

In this chapter, we review the main current applications of ancillary techniques in breast fine needle aspiration biopsy (FNAB) cytology. Contemporary ancillary techniques used in combination with FNAB of the breast range from “classic” immunocytochemistry (ICC) to modern molecular techniques, in particular, next-generation sequencing (NGS). The applications reviewed in this chapter include the primary diagnosis of a breast lesion, the identification of the breast as a primary source of a metastatic lesion, the evaluation of breast prognostic and predictive markers, and the tracking of tumor evolution. This chapter aims to elucidate the complexity of the many challenges traditionally associated with the application of ancillary techniques to FNAB of the breast and provide insights into some of the most cutting-edge and clinical useful application scenarios.