Toowoomba Base Hospital Queensland, Australia
Title: Fine needle aspiration cytology in the diagnosis of parotid masses in a South East Queensland Hospital
Dr Christopher Jackson is a Principal House Officer in ENT at the Toowoomba Hospital in Queensland where he has been based for two years. He graduated from the University of Queensland in 2015 and holds academic title at this institution with ongoing research within the ENT field.
The salivary glands are associated with a wide range of pathologies, some of which are not easily differentiated by clinical or radiographic findings. Fine needle aspiration (FNA) is a safe and readily available pre-operative tool that is frequently used to delineate neoplastic parotid tumours. There is however a wide range of reported variability regarding the sensitivity of FNA cytology in the diagnosis of parotid masses (Henrys et al. ANZ J Surg, 2014). This study was completed to provide further Australian data on the clinical role of FNA cytology in the evaluation of parotid gland lesions. Methodology: Retrospective data was collected from patients at Logan Hospital in South East Queensland from 2006 to 2016. FNA results from 183 patients who underwent parotidectomy during this period were analysed. We compared FNA cytology with formal histological diagnosis post-operatively and conducted statistical analysis of the results. Results: We found FNA cytology was reliable in diagnosing benign parotid gland neoplasms with a sensitivity and specificity of 98.6% and 74.1% respectively. For malignant tumours, FNA was less accurate with a sensitivity and specificity of 84% and 98.6%. The positive predictive value for predicting malignancy was 91.3%. Of malignant tumours in this series the majority (54.2%) were squamous cell carcinomas (33.3%). There were 18 (9.8%) non-diagnostic FNA results, 16.6% (N=3) of these were associated with malignant tumours on final histopathology. Conclusion: This study adds further weight to FNA cytology being a useful investigation for the evaluation of parotid gland lesions. It should not be relied upon in isolation however owing to its lower sensitivity in the diagnosis of malignant parotid tumours. Careful history taking, physical examination, radiological imaging and good clinical judgement should thus be employed in all cases of salivary gland masses.