The Diagnostic Value of B-Mode Sonography in Differentiation of Malignant and Benign Tumors of the Parotid Gland

Introduction: Different imaging modalities are used to evaluate salivary gland diseases, including tumors. Ultrasonography (US) is the preferred method on account of its ease of use, affordability, safety profile, and good tolerance among patients. The aim of this study was to evaluate the role of US in differentiating malignant from benign parotid tumors, in the context of previous controversy in the literature on this subject.   Materials and Methods: A cross-sectional study was performed in patients who presented to Qaem Medical Center with parotid masses and who were candidates for parotidectomy between June 2013 and January 2015. Patients were initially referred for a diagnostic US of the parotid. US examinations were performed and sonographic features were reported. The tumors were then classified as benign or malignant on the basis of literature descriptions of the US features of parotid tumors, and were next diagnosed pathologically. The sensitivity, specificity, positive predictive value, and negative predictive value of US for the purpose of differentiating malignant from benign tumors were then calculated.   Results: Twenty-eight patients (aged 18–92 years) underwent US of parotid masses. Twenty-three tumors were diagnosed as benign and five were diagnosed as malignant. The final histopathologic examination showed 21 benign and seven malignant tumors. The sensitivity, specificity, positive predictive value, and negative predictive value of US for differentiating malignant from benign tumors were calculated as 57%, 95%, 80%, and 87%, respectively.   Conclusion: US has a high specificity in differentiating between malignant and benign tumors. However, fine needle aspiration or core needle biopsy is advocated for an exact diagnosis.