Comparison of preoperative fine-needle aspiration cytology diagnosis and histopathological diagnosis of salivary gland tumors.

We investigated 115 patients with salivary gland epithelial tumors who had undergone preoperative fine needle aspiration cytology (FNAC) of salivary glands and had been diagnosed by postoperative histopathological examination. We compared the findings of preoperative FNAC with their histopathological types in salivary gland tumors, and discuss the results and problems. The diagnostic accuracy, sensitivity, and specificity of preoperative FNAC of salivary glands were 98.2%, 88.2%, and 100%, respectively. The percentage of inadequate specimens was 6.1%. The rates of agreement in the diagnosis of pleomorphic adenoma, Warthin tumor, and basal cell adenoma were 96%, 92.9%, and 55.5%, respectively. The rate of agreement of histopathological types in the malignant tumors was 30%. We realized again not only that the diagnostic accuracy of preoperative FNAC for salivary gland tumors was high, but also that it was a safe, easy-to-perform, clinically very useful diagnostic procedure. However, this study exposed several problems which are the inadequate sampling rate and the difficulty in diagnosing malignant tumors. We have been making efforts to take appropriate specimens by writing comments on the cytological report indicating a re-examination, or by the presence of the clinical laboratory technician at the FNAC procedure. We consider it necessary to adequately re-aspirate the solid portion after cyst fluid aspiration, or to re-perform FNAC at a later date, and to improve the diagnostic accuracy by further experience with more patients.