Accuracy of fine needle aspiration cytology from breast masses in Thailand.

Objective: To evaluate the accuracy and diagnostic performance of fine needle aspiration FNA cytology in diagnoses of breast masses.

Methods: Women who had FNA diagnoses for breast masses and underwent subsequent histopathologic evaluation during January 2003-December 2006 were accessed from the archive of the Anatomical Pathology Department of our institution. Cytologic diagnoses were classified as unsatisfactory, benign, atypical probably benign, suspicious probably malignant, and malignant, and were compared to the histopathologic diagnoses obtained from core needle biopsy, excisional biopsy, or mastectomy to give an assessment of the diagnostic performance of FNA.

Results: A series of 190 breast masses were identified during the study period. The FNA cytological diagnosis was unsatisfactory due to inadequate specimens in eight cases (4.2%). The diagnoses in the remaining 182 cases were: benign lesions in 98 (53.9%); suspicious for malignancy in 31 (17.0%); and malignant in 53 (29.1%). From the subsequent histopathologic diagnoses, 6/98 cases of benign cytology turned out to be malignant lesions (false negatives); 22/31 cases of suspicious cytology were truly malignant while the other nine were benign; and only 1/53 with malignant cytology was benign (false positive), the lesion being a fibroadenoma . The overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 91.2% (95% confidence interval (CI), 87.6%-94.8%), 92.5% (95% CI, 88.7%-96.3%), 90.2% (95% CI, 85.9%-94.5%), 88.1% (95% CI, 83.4%-92.8%) and 93.9% (95% CI, 90.4%-97.4%), respectively.

Conclusions: FNA cytology is highly accurate for diagnosis of breast masses. However, the clinician should correlate FNA cytological results with physical examination and imaging findings to prevent false negative and false positive events and to obtain optimal management for their patients.