Preoperative accurate prediction of final histopathologic diagnosis is essential in the management including surgical planning of parotid tumors. 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. This study was conducted as 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, the accuracy and the specimen adequacy were analyzed according to the tumor components. The US-FNA group showed significantly higher rates of non-diagnostic results than in the US-CNB group (44.0% vs. 13.8%, p=0.002). Diagnostic accuracy was also significantly higher in US-CNB than US-FNA (95.4% vs. 64.0%, P < 0.001), and the non-diagnostic result of US-FNA was the main factor in reducing accuracy. Meanwhile, in US-FNA, a significant decrease in accuracy was observed in cystic-predominant tumors compared to solid-predominant tumors (20.0% vs. 75.0%, p=0.040). US-CNB has superiority in both sample adequacy and diagnostic accuracy compared to US-FNA in preoperative diagnosis of parotid tumors, and especially more active use in cystic-predominant tumors could be considered.

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