Microwave ablation of benign parotid gland tumors under ultrasound guidance: a multicenter retrospective case series.

Background: Surgical resection for benign parotid gland tumors is associated with high complication rates, and thus there is in acute need for minimally invasive alternatives. This study aimed to examine the feasibility, safety, and efficacy of ultrasound-guided microwave ablation (MWA) for benign parotid gland tumors. Methods: A retrospective multicenter study was conducted on 13 consecutive patients clinically diagnosed with parotid gland mass and suspected parotid gland tumors from July 2013 to June 2018. All patients underwent core needle biopsy, and parotid gland tumors considered benign based on the biopsy results were treated with ultrasound-guided MWA. The ablated area of the parotid gland was evaluated through dynamic ultrasound imaging, and complications related to needle biopsy and ablative treatment were followed up, with a follow-up ultrasound performed in the third month after MWA. Results: A total of 13 parotid gland tumors underwent core needle biopsy over 5 years. Of these, 12 were benign tumors, including six pleomorphic adenomas, four Warthin's tumors, one dermoid cyst, and one lymphoid nodular hyperplasia, all treated with MWA. Patient age ranged from 10 to 79 years (median, 60.5 years), with tumor diameters ranging from 17.8 to 49 mm (median, 26.15 mm). MWA was performed for 70-598 s (median, 155 s), with complete absorption occurring in 8-37 months (median, 23.5 months). No residual tumors or serious complications were observed after ablation. Conclusions: Ultrasound-guided MWA can serve as a minimally invasive alternative to open surgery for the treatment of benign parotid gland tumors and involves only limited side effects and minor complications.