Accuracy of Fine Needle Aspiration Cytology of Salivary Gland Lesions: Routine Diagnostic Experience in Bangkok, Thailand

Fine needle aspiration (FNA) cytology is well accepted as a safe, reliable, minimal invasive and cost-effectivemethod for diagnosis of salivary gland lesions. This study evaluated the accuracy and diagnostic performance ofFNA cytology in Thailand. A consecutive series of 290 samples from 246 patients during January 2001-December2009 were evaluated from the archive of the Anatomical Pathology Department of our institution and 133specimens were verified by histopathologic diagnoses, obtained with material from surgical excision or biopsy.Cytologic diagnoses classified as unsatisfactory, benign, suspicious for malignancy and malignant were comparedwith the histopathological findings. Among the 133 satisfactory specimens, the anatomic sites were 70 (52.6%)parotid glands and 63 (47.4 %) submandibular glands. FNA cytological diagnoses showed benign lesions in 119cases (89.5 %), suspicious for malignancy in 3 cases (2.2 %) and malignant in 11 cases (8.3%). From the subsequenthistopathologic diagnoses, 3/133 cases of benign cytology turned out to be malignant lesions, the false negativerate being 2.2 % and 1/133 case of malignant cytology turned out to be a benign lesion, giving a false positive ratewas 0.8%. The overall accuracy, sensitivity, specificity, positive predictive value and negative predictive valuewere 97.0% (95% CI, 70.6%-99.4%), 81.3% (95% CI, 54.4%-96.0%), 99.1% (95% CI, 95.4%-100%), 92.9%(95% CI, 66.1%-99.8), 97.5% (95% CI, 92.8%-99.5%), respectively. This study indicated that FNA cytology ofsalivary gland is a reliable and highly accurate diagnostic method for diagnosis of salivary gland lesions. It notonly provides preoperative diagnosis for therapeutic management but also can prevent unnecessary surgery.