Critical clinical appraisal of the role of ultrasound guided fine needle aspiration cytology in the management of parotid tumours.
OBJECTIVE: Fine needle aspiration cytology is a well established tool for investigating many head and neck conditions. Its application in parotid tumours is, however, controversial. This article is aimed at defining the role of ultrasound guided fine needle aspiration cytology (FNAC) in the diagnostic work up of parotid tumours. The accuracy and utility of FNAC of parotid tumours was also assessed. DESIGN: Retrospective case note review. SETTING: District general hospital. PARTICIPANTS: Review of 69 patient records who had parotid surgery under one surgeon's care (JS). Clinical opinion, FNAC results and final pathology findings were examined. MAIN OUTCOME MEASURES: The results of the FNAC were compared to the histopathological diagnosis obtained from the surgical specimen. RESULTS: Histological evaluation revealed 13 malignant tumours and 56 benign lesions. The overall sensitivity of FNAC was 84.6 per cent and specificity was 96.4 per cent. We noted 11 true positive, 54 true negative, two false negative and two false positive results. Positive predictive value for diagnosing malignancy was 84.6 per cent and negative predictive value for malignancy was 96.4 per cent. The overall accuracy of FNAC of parotids in this study was 94.2 per cent. CONCLUSIONS: FNAC results provide useful preoperative information. FNAC enables more reliable patient counselling and reduces pathological surprises. Pre-operative recognition of malignant tumours may help prepare both the surgeon and patient for an appropriate surgical procedure. Its enhancement of the pre-operative recognition of malignant parotid tumours may alert more stringent attention to the operative margin and hence better tumour clearance. Ultrasound guided FNAC was found to be highly specific for malignancy and its sensitivity for malignancy was good.