Fine needle aspiration vs. surgical pathology specimen in salivary gland tumors: a study of diagnostic accuracy and predictive value

BACKGROUND:
While the present literature emphasizes that surgical biopsies are the gold standard in diagnosing salivary gland tumors, several studies highlight the role of fine needle aspiration (FNA) due to its high diagnostic yield and minimally invasive nature. However, the role of FNA and its accuracy in diagnosing salivary gland tumors compared to surgical biopsies is poorly investigated in the Eastern region of Saudi Arabia.


OBJECTIVE:
Assess the diagnostic accuracy of FNA in salivary gland tumors as compared to histopathological findings from surgical specimens. Identify sources of diagnostic discrepancies between FNA and surgical biopsies.


DESIGN:
Retrospective diagnostic accuracy study


SETTINGS:
King Fahd Hospital of the University in Eastern Province, Al Khobar, Saudi Arabia


PATIENTS AND METHODS:
Patients with confirmed diagnosis of salivary gland tumor who underwent both FNA and surgical biopsy between 2014-2024. FNA was performed under ultrasound (US) guidance and examined by two consultant pathologists. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to evaluate the diagnostic accuracy of FNA.


MAIN OUTCOME MEASURES:
FNA diagnostic accuracy compared to histopathological findings from surgical specimens.


SAMPLE SIZE:
40 cases


RESULTS:
A total of 267 cases were considered in this study, of which only 40 cases were included. FNA had a high specificity of 100% (95% CI: 85.8%-100%) but a low sensitivity of 23.08% (95% CI: 5.0%-53.8%). The PPV is 100% (95% CI: 29.2%-100%). The NPV is 70.6% (95% CI: 64.0%-76.4%). Finally, the overall accuracy is 73% (95% CI: 55.9%-86.2%).


CONCLUSION:
Our study supports the utility of FNA as a diagnostic modality for salivary gland tumors, demonstrating high specificity with variable sensitivity. The observed false negative rate emphasizes the need for cautious interpretation of negative results, necessitating confirmatory histopathological studies. The findings highlight the influence of sample size on cytology performance, with smaller studies reporting lower sensitivity compared to larger multi-center analyses.


LIMITATIONS:
Sample size, retrospective design, data extraction, incomplete data.