Ultrasound-guided core needle biopsy of parotid gland swellings

Objective: To determine whether ultrasound-guided core needle biopsy is a safe and reliable investigation in cases of parotid swelling in which fine needle aspiration cytology has failed to give a definitive diagnosis. Design: Analysis of 66 ultrasound-guided core biopsy specimens of the parotid gland (the largest series reported thus far) sample number refers to histological samples throughout the paper. Subjects: All the 184 cases of parotid surgery with a histological diagnosis were included. Main outcome measures: The sensitivity, positive predictive value and diagnostic accuracy of fine needle aspiration cytology and ultrasound-guided core needle biopsy, as compared with the final histological analysis. Results: Of a total of 184 patients, 89.1 per cent (164/184) had benign parotid lesions excised. The sensitivity, positive predictive value and diagnostic accuracy of fine needle aspiration cytology for benign lesions were 76.2, 84.2 and 87.5 per cent, respectively, and those of ultrasound-guided core needle biopsy were 91.7, 98.2 and 96.4 per cent, respectively. Twenty of 184 patients (10.9 per cent) had malignant lesions. The sensitivity, positive predictive value and diagnostic accuracy of fine needle aspiration cytology for detection of malignant lesions were 60, 75 and 75 per cent, respectively, while those of ultrasound-guided core biopsy were 89, 100 and 100 per cent, respectively. Non-diagnostic rates were 25.8 per cent for fine needle aspiration cytology and 4.5 per cent for ultrasound-guided core biopsy. Only one case of complications (a sub-clinical haematoma) occurred in the ultrasound-guided core biopsy group. Conclusion: We propose ultrasound-guided core needle biopsy as a very safe and effective toot in cases of parotid swelling in which fine needle aspiration cytology has failed to give a definitive diagnosis.