Fine needle aspiration cytology of salivary glands: a 15-year retrospecitive analysis

초록

Background The aim of this study evaluate the sensitivity, specificity and the most common diagnostic pitfalls of FNA of salivary gland lesions performed at a single university hospital over a time period of 15 years. Methods A total 603 salivary gland FNAs was performed at Inha University Hospital from 1997 to 2012. FNA cytologic findings and final pathologic findings were examined. Results The cytologic diagnoses included 25 malignancies, 15 suspicious for malignancies, 32 atypia, 435 negative and 96 unsatisfactory. 274 cases had histologic follow-up (45%). There were 6 false negative: 4 mucoepidermoid carcinoma, 1 carcinoma ex pleomorphic adenoma and 1 malignant lymphoma. There were 4 false positive: 2 Warthin’s tumor and 2 chronic sialadenitis. The overall accuracy in distinguishing benign from malignant lesions was 96.4%. The sensitivity and specificity were 77% and 98%, respectively. Benign cases with the highest false-positive rates were Warthin’s tumor (50% false positive). Malignant cases with highest false-negative rates were low grade mucoepidermoid carcinoma (66% false negative). Selected review of the the most discordant individual cases revealed possible explanations for some of the interpretive errors. Conclusions The data confirm the difficulty associated with interpretation of salivary gland FNA specimens. Ten cases had discrepancies in benign versus malignant diagnoses with six cases being false negative. The errors in these FNA diagnoses were due to sampling error, observation error and interpretational error. Cytopathologists should be aware of the potential false positive and false-negative interpretations that can occur in FNAs from this organ site in order to minimize the possibility of diagnostic errors. Keywords Salivary gland tumor fine needle aspiration cytology