# Diagnostic Accuracy of Fine-Needle Aspiration Cytology in the Diagnosis of Parotid Gland Swellings

## TL;DR

This study evaluates how accurate fine-needle aspiration cytology is in diagnosing parotid gland swellings, finding it to be highly specific and useful for distinguishing benign from malignant cases.

## Contribution

The study provides a detailed assessment of FNAC's diagnostic accuracy in parotid gland lesions using real-world clinical data.

## Key findings

- FNAC showed high specificity (98.83%) and accuracy (91.07%) in diagnosing parotid gland swellings.
- Pleomorphic adenoma was the most common pathology observed in both FNAC and histopathological analysis.
- FNAC's high positive predictive value (94.4%) and positive likelihood ratio (55.88) support its use as a diagnostic tool.

## Abstract

Background

Parotid gland swellings are the most common salivary gland lesions. Fine-Needle Aspiration Cytology (FNAC), apart from being the first-line diagnostic tool in the evaluation of parotid gland swellings, plays an integral role in planning both surgical and non-surgical therapy.

Objectives

To determine the diagnostic accuracy of FNAC in the evaluation of parotid gland swellings.

Methodology

Medical records of all patients who underwent surgery for parotid gland lesions at Ramaiah Medical College and Hospital, Bengaluru, Karnataka, since 2010 were retrospectively analyzed. Demographic data, FNAC reports, and final histopathology reports were extracted, assessed, and statistically analyzed.

Results

Out of the 193 patients who underwent surgery for parotid gland swelling during the study period, 112 cases were included in the study. The cohort consisted of 67 male and 45 female patients, with a mean age of 50 years. FNAC diagnosed 94 patients with benign disease and 18 patients with malignant disease. Final histopathological analysis of post-surgical specimens revealed that 86 cases had benign pathology, while 26 had malignant disease. Pleomorphic adenoma was the most common pathology observed in both FNAC and histopathological analysis.

The diagnostic performance of FNAC in identifying parotid gland pathology was as follows: sensitivity, 65.38%; specificity, 98.83%; accuracy, 91.07%; positive predictive value (PPV), 94.4%; negative predictive value (NPV), 90.42%; positive likelihood ratio (LR+), 55.88; and negative likelihood ratio (LR-), 0.35.

Conclusions

Our findings demonstrate that FNAC has good accuracy in distinguishing benign lesions from malignant ones. FNAC is a readily available, repeatable, inexpensive, minimally invasive, and relatively painless outpatient procedure with no known serious complications. While a relatively low sensitivity may limit its standalone diagnostic value, its high specificity, PPV, NPV, and LR+ underscore its importance as a valuable diagnostic tool in the evaluation of parotid gland swellings.