Non-Diagnostic

The adequacy criteria for salivary gland cytology have been clearly defined in the First Edition of the Milan System for Reporting Salivary Gland Cytopathology. The same criteria have been tested and validated in several studies. Here, advantages and limitations of adequacy criteria are discussed. Both qualitative and quantitative aspects of the specimen are needed to define its adequacy. Many factors including the aspiration technique (manual versus image-guided), caliber of the FNA needle, nature of the lesion (solid versus cystic), sample preservation method, and presence of background blood due to hemorrhage among others can influence the adequacy of a salivary gland FNA. Adhering to a practical set of criteria for sample adequacy, even if empirical, will help to ensure a low false negative rate, and lead to better overall patient care. Based upon non-diagnostic rates reported in the recent literature as well as the author’s own experiences, it is estimated that the rate of non-diagnostic salivary gland FNAs should not exceed 20%.