The usefulness of fine-needle aspiration cytology in the management of parotid gland masses at Chris Hani Baragwanath academic hospital

Mdletshe, Fanelesibonge Brightness
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BACKGROUND: Salivary gland tumours account for 3% of all head and neck tumours and 85% salivary gland tumours arise from the parotid gland. 80% of the parotid gland tumours are benign while 20% are malignant. The gland is also the site of various non-neoplastic conditions that can present a diagnostic challenge clinically and on investigations. Fine needle aspiration cytology (FNAC) is relied upon for preoperative workup but the vast number of histological subtypes including heterogeneity of tumours compounds cytological analysis. However, FNAC still forms an integral part of preoperative decision-making. It can assist in distinguishing between neoplastic and non-neoplastic conditions and often forms the basis of a decision to not proceed to surgical management in some patients with parotid gland masses. AIM: To determine the diagnostic value of fine-needle aspiration cytology in patients presenting with parotid gland masses and CHBAH. METHODS: A retrospective review of records of patients that had preoperative fine-needle aspiration cytology (FNAC) for parotid gland mass followed by parotidectomy over a 5 year period, between January 2013 and December 2017. Information was retrieved from patient discharge summaries kept in the ENT Department, the operating theatre record and histopathology reports from the National Health Laboratory Services (NHLS) database. The data collected included age, sex, preoperative FNAC results, post-operative histology results, presenting symptoms and clinical signs. RESULTS: A total of 77 patient records were retrieved and reviewed. 63 patients met the inclusion criteria. 52% of the patients were male and 48% were female. Their average age was 43.3 years (range: 23-74 years). 71% (45/63) of the tumours were benign, and 21% (13/63) were malignant while 8% (5/63) showed inflammatory lesions on FNAC. (41/45) 91.1% of the benign tumours on FNAC had a corresponding benign tumour result on histology. 30.8% (4/13) cases identified as malignant on FNAC showed a corresponding malignant result on histology. The sensitivity and specificity of FNAC to detect malignant tumours was 33.3% and 97.6% respectively. The negative and positive predictive values were 83% and 80% whilst the accuracy was calculated at 83%. CONCLUSION: FNAC for parotid gland masses is more reliable in the diagnosis of benign than malignant tumours. Lymphoid lesions and non-neoplastic diseases often result in false positive and negative diagnoses on FNAC. The accuracy of FNAC in correctly identifying malignant tumours is low and surgical decision should rely on combination of findings from clinical and imaging investigations.
Research Report M. Med