Ultrasonography techniques in the preoperative diagnosis of parotid gland tumors – an updated review of the literature

Abstract

Preoperative diagnosis of parotid tumors plays a crucial role in selecting and planning the surgical treatment. Ultrasound (US) with its modern techniques can contribute to the differential diagnosis of parotid tumors. This paper aims to achieve a comprehensive review of the ultrasound techniques used in the differential diagnosis of parotid tumors, based on the latest literature data. Considering that most parotid gland tumors are located in the superficial lobe, US is frequently the first imaging technique used for the diagnosis of parotid tumors. Sonoelastography can provide additional data on the elasticity of parotid tumors, but there is an overlap between malignant and benign parotid tumors parameters. Contrast-enhanced ultrasound adds value to conventional ultrasound and allows a more complete characterization of parotid tumors. Many authors have reported promising results using contrast-enhanced ultrasound in the differential diagnosis of parotid tumors. Multiparametric ultrasound with a careful and systematic approach usually allows an accurate differential diagnosis of parotid tumors.

Preoperative Multiparametric Ultrasound and Fine Needle Aspiration Cytology evaluation of parotid gland tumors: which is the best technique?

“…They concluded that there was a correlation between the micro-and the macro-vascularization of the lesions respectively evaluated with CEUS and Color-Doppler US, but the predictive value of each single technique was not so effective and a multiparametric assessment was required to increase the specificity and PPV in the diagnosis of malignant parotid lesions and the sensitivity in the differential diagnosis between pleomorphic adenomas and Warthin's tumors [37]. Another recent review confirmed that MPUS, specially if includes CEUS, enables the differential diagnosis of parotid tumors [1,20].…”

“…The following patterns were considered at the evaluation with baseline ultrasound: 1) suspected malignant lesions: nodular appearance, irregular or frankly infiltrating margins, heterogeneous hypoechoic structure, calcifications and hypo-anechoic necrotic-hemorrhagic internal areas, associated regional lymphadenopathy [1,15]; 2) pleomorphic adenoma: homogeneous, lobulated, hypoechoic structure with posterior wall enhancement, with or without calcifications, poor vascularization [1,16]; 3) Warthin's tumor: oval, hypoechoic mass, capsulated with anechoic and hypervascularized areas [1,17,18].…”

“…Parotid neoplasms are the most frequent salivary gland tumors; 60% of them are benign and are mainly located in the superficial lobe (76% of cases), while malignant lesions usually involve the deep lobe or both lobes. Tumor location, extension and correct preoperative characterization play a crucial role in deciding the proper treatment [1][2][3][4].…”

“…Characterization of parotid tumors is relevant in planning surgery and in predicting possible complications or recurrencies. Imaging techniques such as Ultrasound (US), Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) are frequently used for the evaluation of parotid lesions, although none of them can guarantee an accurate differ-ential diagnosis between benign lesions and malignancies [1]. The sensitivity and specificity of Fine Needle Aspiration Cytology (FNAC) varies according to lesion location and size, and the pathologist's experience.…”

“…Recently, some authors have focused on US coupled with various innovative techniques, under the name of Multiparametric Ultrasound (MPUS) [14]. These techniques, such as Contrast-Enhanced Ultrasound (CEUS) and Ultrasound-Elastography (USE), are used to increase the effectiveness and the accuracy of B-mode US in the differential diagnosis of parotid masses and decrease the need for invasive techniques [1,2].…”