Fine Needle Aspiration Cytology of Benign Salivary Gland Tumors with Myoepithelial Cell Participation: An Institutional Experience of 575 Cases

OBJECTIVE: The aim of this study was to evaluate the diagnostic accuracy of fine needle aspiration (FNA) cytology of benign salivary gland tumors with myoepithelial cell participation, namely, pleomorphic adenoma, basal cell adenoma and myoepithelioma, at a single institution over a period of 10 years. STUDY DESIGN: This study was based on 575 cytologic and matching histological samples (534 pleomorphic adenomas, 26 basal cell adenomas and 15 myoepitheliomas). RESULTS: In most cases (393/534) of pleomorphic adenoma, a precise diagnosis was given. However, only 2 cases of basal cell adenoma and 1 case of myoepithelioma were diagnosed definitively. Descriptive diagnosis, instead of a definite diagnosis, was rendered in 16.9% of pleomorphic adenomas, 53.8% of basal cell adenomas and 40.0% of myoepitheliomas. Among all cases, the possibility of malignancy was raised in 5.2% of pleomorphic adenomas, 15.4% of basal cell adenomas and 20.0% of myoepitheliomas with a variable degree of suspicion. CONCLUSION: In some cases, the distinction between these three neoplasms remains difficult in that all exhibit some degree of myoepithelial participation. However, FNA showed a high diagnostic accuracy in diagnosing benign salivary tumors with myoepithelial differentiation, and triage into this category provides sufficient information for clinicians to make treatment decisions.