The Usefulness of Ultrasound-Guided Core Needle Biopsy Compared to Fine Needle Aspiration in Pre-Operative Diagnosis of Cystic-Predominant Parotid Tumors

Abstract

Background and Objectives Accurate preoperative prediction of final histopathologic diagnosis is essential in parotid tumor management, which also includes surgical planning. As a preoperative diagnostic examination for parotid tumors, the accuracy of ultrasound-guided fine needle aspiration (US-FNA) and ultrasound-guided core needle biopsy (US-CNB) was compared, and factors affecting the accuracy of diagnosis and adequacy of the specimen were analyzed.Subjects and Method This study was conducted as a retrospective analysis of 90 patients with parotid tumor who had undergone parotidectomy after pre-operative ultrasound-guided biopsy. We divided the study subjects into US-FNA and US-CNB groups and evaluated the diagnostic accuracy by comparing the pre-operative results with the final histopathologic diagnosis after surgery. In addition, accuracy and specimen adequacy were analyzed according to tumor components.Results The US-FNA group showed significantly higher rates of non-diagnostic results than the US-CNB group (44.0% vs. 13.8%, <i>p</i>=0.002) did. Diagnostic accuracy was also significantly higher in US-CNB than in US-FNA (95.4% vs. 64.0%, <i>p</i><0.001), and the non-diagnostic result of US-FNA was the main factor in reducing accuracy. Meanwhile, in both cysticpredominant tumors and solid-predominant tumors (94.8% vs. 75%, <i>p</i>=0.023), US-CNB showed significantly better accuracy than US-FNA (100.0% vs. 20.0%, <i>p</i>=0.010) did.Conclusion US-CNB has superiority in both sample adequacy and diagnostic accuracy compared to US-FNA in preoperative diagnosis of parotid tumors, and it seems necessary to consider its use more actively in the diagnosis of cystic-predominant tumors.