Fine Needle Aspiration Cytology of Adenomyoepithelioma of the Breast: Cytologic Findings and Histologic Correlations

Fine‐needle aspiration (FNA) cytology was performed on a 71‐year‐old woman with the right breast painless tumor (12 mm in diameter). FNA smears were cellular, and two types of cells were observed as main components. One was benign ductal epithelial cells and the other was associated with larger nuclei, prominent nucleoli, and ample clear cytoplasm. However, the latter cells lacked nuclear atypia and hyperchromasia and looked benign as well. Both types of cells appeared separately as sheets but also mixed in cell clusters. The latter cells were considered myoepithelial cells and the close associated proliferation of ductal epithelial cells and myoepithelial cells suggested adenomyoepithelioma as the cytological diagnosis. Histologically, the diagnosis of adenomyoepithelioma was confirmed. The cytological findings are described in detail, and their relation to the histological characteristics is discussed. The usefulness of cytologic findings in predicting histology is also analyzed.