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The Role of Fine Needle Aspiration Cytology and Frozen Section in the Evaluation of Parotid Lesions: Our Institution’s Experience
Y F Soh*, R Y Zhu*, J W Kam**, X Y Huang*
* Department of Otolaryngology, Head & Neck Surgery, Changi General Hospital
** Clinical Trials & Research Unit, Changi General Hospital
Introduction:
The role and value of fine-needle aspiration cytology (FNAC) in the diagnosis and management of parotid gland lesions remains a topic of controversy. The literature reports significant variability in the accuracy of FNAC for diagnosis of parotid lesions. Supplemental information from intra-operative frozen section (FS) analysis of parotid lesions can significantly influence the extent of surgery, more so in cases where there is a suspicion of malignancy and pre-operative FNAC is non-diagnostic. Distinguishing neoplastic from non-neoplastic lesions and benign from malignant neoplasms of the parotid gland plays a critical role in deciding on patient management.
Aims:
The aim of this study was to review our institution’s experience with diagnostic accuracy of FNAC and FS in the evaluation of parotid gland lesions.
Methods:
A retrospective review of all patients who underwent parotidectomies in an 8-year period between 2008 to 2016 at a single tertiary institution was performed. The accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and histological concordance of FNAC and FS for various parotid lesions were calculated.
Results:
A total of 130 patients were included in this study. The most common lesion found on final histology was pleomorphic adenoma. 92.4% of patients underwent FNAC and 56.5% of patients underwent intraoperative FS for their parotid lesions. FNAC had a sensitivity and specificity of 93.4% and 100% in terms of differentiating between neoplastic and non-neoplastic lesions. In diagnosing malignant neoplasms, the accuracy of FNAC was 98.6% with a PPV of 100% while the accuracy of FS was 97.3% with a PPV of 100%. Overall histological concordance of FNAC and FS for parotid neoplasms was 80.3% and 87.9% respectively.
Conclusion:
Our results suggest that FNAC is a useful tool in the differentiation between neoplastic and non-neoplastic lesions. When used in conjunction with FS, they are complementary in the diagnosis of malignant parotid neoplasms.
References:
1. Schmidt R L et al. A Systematic Review and Meta-Analysis of the Diagnostic Accuracy of Fine-Needle Aspiration Cytology for Parotid Gland Lesions. Am J Clin Pathol 2011; 136:45-59.
2. Schmidt R L et al. A Systematic Review and Meta-Analysis of the Diagnostic Accuracy of Frozen Section for Parotid Gland Lesions. Am J Clin Pathol 2011; 136:729-738.
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