Fine-needle aspiration cytology for parotid lesions, can we avoid surgery?

OBJECTIVE Salivary gland neoplasms are rare tumours, with most arising in the parotid gland. Fine-needle aspiration cytology (FNAC) is a common method for preoperative evaluation of parotid masses, although its usefulness is controversial. This study was designed to evaluate the accuracy of FNAC in a large cohort of patients, with emphasis on diagnosis of benign tumours and especially Warthin tumour which can be managed conservatively. STUDY DESIGN Retrospective case series with chart review. SETTING Tertiary medical centre. SUBJECTS AND METHODS From 1991 to 2014, all patients 18 or older with both preoperative FNAC and postoperative pathology report were included. Patients with a history of head and neck malignancy or chronic sialoadenitis and patients who had undergone prior oncological treatment were excluded. RESULTS 470 patients were available for analysis. Overall accuracy was 82.6%. Positive predictive value (PPV) varied between 88.6% and 94.3% for pleomorphic adenoma and 77.1%-100% for Warthin tumour, with values varying depending on different characteristics of patients (eg age, smoking status). For pathologically proven malignant tumours, the FNAC diagnosis was benign or non-diagnostic in 26% of the cases. CONCLUSION Fine-needle aspiration cytology has limited utility in confirming a benign diagnosis of a parotid mass for most patients, although for some subpopulations, the PPV may be high enough to defer surgery.