Accuracy of FNAC and CT in the differentiation of benign and malignant parotid tumours in a case series

Introduction: Parotid tumours, in addition to the wide variety of types, are histologically complex. Differentiating between benign and malignant tumours in preoperative diagnosis is important in deciding the type of surgery required. Fine needle aspiration cytology (FNAC) is a simple, quick, low-cost, low-invasive and well-tolerated tool used in the preoperative diagnosis of these tumours. Material and methods: we calculated the sensitivity, specificity, predictive positive value (PPV) and negative predictive value (NPV) of FNAC and computed tomography (CT) in the differentiation of benign and malignant parotid tumours operated between 2010 to 2014 in the oral and maxillofacial surgery department of the University Hospital Miguel Servet. Results: The sensitivity of FNAC is 50%, while the specificity is high, at 98.7%. FNAC offers high reliability in the diagnosis of malignant tumours, despite its low sensitivity. However, when the diagnosis is indeterminate or benign, other than pleomorphic adenoma or Whartin tumour, the reliability to exclude malignancy decreases. Conclusion: The low sensitivity of FNAC to differentiate malignant from benign parotid tumours, means that we cannot rule out other diagnostic tests, clinical symptoms and especially the intraoperative vision of each surgeon. Especially when the diagnosis is indeterminate. Nevertheless, it is a technique used in a systematised way and helps in pre-surgical decision-making. (C) 2017 Elsevier Espana, S.L.U. and Sociedad Espanola de Otorrinolaringologia y Cirugia de Cabeza y Cuello. All rights reserved.