US in preoperative evaluation of parotid gland neoplasms

Salivary gland neoplasms account for only 3% of all tumors of the head and neck area, but as they represent a wide variety of histological types, they are a big diagnostic challenge. The cornerstone of salivary gland neoplasm treatment, both for the benign and malignant lesions, is surgery. The main goal of the therapy is not only to achieve complete surgical tumor resection, but also to preserve adjacent structures (facial nerve, parapharyngeal space structures). Ultrasonography is an examination commonly used in the preoperative diagnosis of the lesions localized within salivary glands. Very often it is the only diagnostic imaging method used in these cases. The aim of the study was to establish diagnostic value of US examination and its parameters for the assessment of parotid gland tumors. A prospective study was performed on a group of 51 patients with parotid gland neoplasms, who over a period of 3 years underwent surgery in Otolaryngology and Laryngological Oncology Department with Craniomaxillofacial Surgery Department of Central Clinical Hospital of Ministry of Defence in Warsaw. All the included patients underwent US examination in the preoperative period. The parameters selected for the assessment were: ill-defined tumor margins, tumor vascularity and the presence of enlarged regional lymph nodes. The results of imaging examination were compared to the final diagnosis based on pathological examination of the surgical specimen. The parameters of the US examination such as sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the evaluation of parotid gland tumors were established based on the examination results. An analysis was performed and ill-defined parotid tumor margins turned out to be a US parameter with higher diagnostic value for differentiating benign and malignant lesions than increased tumor vascularity. The presence of enlarged regional lymph nodes with blurred echostructure on the US examination had little value for differentiating lesions. The sensitivity of the US examination in terms of detecting malignant parotid gland neoplasms increased significantly in the setting of simultaneous assessment of several parameters.