Values of fine‐needle aspiration cytology of parotid gland tumors: A review of 996 cases at a single institution

Abstract

Background We evaluated the diagnostic accuracy of fine‐needle aspiration cytology (FNAC) in a large series of benign and malignant parotid tumors. Methods The FNAC diagnosis of 821 benign and 175 malignant parotid tumors managed at our department between 1999 and 2017 was correlated with the final histology. Results FNAC made a correct histopathological diagnosis in 72% of the benign parotid tumors; however, FNAC provided a correct grade in only 34% of the malignant tumors. FNAC correctly identified the histology of 94% of pleomorphic adenomas subsequently confirmed by histopathological examination. The sensitivity, specificity, and diagnostic accuracy of FNAC for detecting malignancy were 82.3%, 98.7%, and 95.9%, respectively. Conclusion FNAC generally provided the correct histological diagnosis for benign tumors. However, the histological evaluation and grading of malignant tumors were poor. Although FNAC showed good sensitivity, specificity, and accuracy, its sensitivity decreased when nondiagnostic cases were included in the analysis.

Preoperative evaluation and treatment consideration of parotid gland tumors

“…We found previously that 10% of submandibular gland tumors with a benign cytology turned out malignant, 20 and Suzuki et al 14 showed this risk to be even 14% in parotid tumors. Thus, a risk for malignancy remains: in our series, one such tumor turned out to be carcinoma ex PA.…”

“…In addition, 36% were Warthin tumors, which is significantly more than in other series (8%-15%), 15,17 but reflects figures presented by Perkins et al 18 Most malignant tumors in our study were SDCs (31%), a significantly differing finding from other studies where other tumor types predominate. 13,14,16,19 We encountered no adenoid cystic carcinomas (ACC), but noteworthy, the overall number of malignancies remained low. In our previous study of submandibular gland neoplasms, ACC was the most common type of malignancy.…”

“…Malignant parotid gland tumors represented 10% of all neoplasms, which is in line with the study published by Bradley et al in 2013 12 but significantly less than in some other recent studies reporting 14% to 32%. [13][14][15][16][17] Due to the national health care system with centralized treatment we were able to gather a patient series that represents the true distribution of benign and malignant tumors within our geographic area. We report an annual incidence of 0.88/ 100 000 inhabitants for malignant parotid neoplasms, which follows the estimation presented previously from the UK.…”

“…Certain cytological findings, such as those showing PA, are considered highly reliable with a correct diagnosis in 91% to 94% of cases. 14,20,24 Somewhat less reliable figures have also been presented:…”

“…In practice, patients are well counseled to acknowledge the risks related to parotid gland surgery, 31 and when all cytological criteria for Warthin tumor are fulfilled, the diagnosis is nearly 100%. 14,32,33 We had 15 patients with a final histopathology showing a cyst.…”