A 10-year experience in preoperative ultrasound imaging for parotid glands’ benign neoformations

Salivary gland neoplasms represent less than 4% of all head and neck lesions, being 80% in the parotid gland and usually benign. Imaging plays a key role in the evaluation of parotid gland masses. Ultrasound is cheap, with an excellent resolution and a safe real time assessment making it an ideal first evaluation option. Conversely, MRI is considered a second-line pre-surgery exam used to determine the location, the extension and the signal features of a parotid lesion. Both US and MRI are poorly reliable for predicting histology, therefore a fine-needle aspiration cytology (FNAC) is usually needed. In our retrospective study, we examined 263 patients with parotid diseases and a FNAC positive for a benign neoplasm, who underwent surgery between 2010 and 2020, in the departments of Otorhinolaryngology and Maxillofacial surgery in Verona. We compared a group of 126 patients preoperatively evaluated with ultrasound and a control group of 137 patients studied through third level imaging (usually MRI). In our case series, both third level imaging and US were used in equal measure, despite the lesion size. We found the recurrence rate to be almost the same between the two diagnostic methods and we saw that the patients studied through third level preoperative imaging had a higher complication rate and a worse facial nerve outcome. In our opinion, for patients with a FNAC positive for benign lesion the exclusive use of ultrasound imaging provides enough information to study the neoplasm while allowing for a faster and cheaper preoperative evaluation.