Comparative Study of Qualitative and Quantitative Analyses of Contrast-Enhanced Ultrasound and the Diagnostic Value of B-Mode and Color Doppler for Common Benign Tumors in the Parotid Gland.

Meiying Yan,Liyu Chen,Dong Xu,Lingyan Zhou

doi:10.3389/fonc.2021.669542

Meiying Yan, Liyu Chen + Show 2 more

Open Access

https://doi.org/10.3389/fonc.2021.669542

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Abstract

PurposeTo preliminarily identify three common benign parotid gland tumors: pleomorphic adenomas (PA), Warthin tumors (WT), and basal cell adenomas (BCA) by qualitative and quantitative analyses using contrast-enhanced ultrasound (CEUS).MethodsPreoperative images of parotid gland masses were analyzed, including 129 cases of ultrasonography (US) and color Doppler sonography (CDS) and 110 cases of qualitative and quantitative CEUS. The diagnosis was confirmed by postsurgical pathology outcomes.ResultsPA presented low and heterogeneous enhancement and echo-free area, whereas most WT and BCA presented with high and relatively homogeneous enhancement. Compared with WT and BCA groups, a “slow in” pattern was more common in the PA group and a “slow out” pattern was more frequently noted in the WT group than in the PA and BCA groups. The unique features of qualitative CEUS in the PA group enable distinguishing PA from the 2 other groups. The further distinction among the groups was made based on quantitative parameters of time-intensity curves (TICs), which revealed that the mean peak intensity (PI), mean transit time (MTT), the area under the curve (AUC), and time from peak to one half (HT) exhibited significant differences. ROC analysis was next applied to determine the optimal cutoff points to predict the diagnostic tendency among the groups. When the rising slope (RS) was >2.145, the possibility of BCA was greater than WT.ConclusionsCEUS ultrasound is of significant value in the differential diagnosis of the 3 common benign parotid gland masses.

Highlights

Tumors of the salivary gland are relatively rare, constituting a mere 5.0% of all head and neck tumors
Compared with Warthin tumor (WT) and basal cell adenoma (BCA) groups, a “slow in” pattern was more common in the Pleomorphic adenomas (PA) group and a “slow out” pattern was more frequently noted in the WT group than in the PA and BCA groups
The further distinction among the groups was made based on quantitative parameters of time-intensity curves (TICs), which revealed that the mean peak intensity (PI), mean transit time (MTT), the area under the curve (AUC), and time from peak to one half (HT) exhibited significant differences

Summary

Introduction

Tumors of the salivary gland are relatively rare, constituting a mere 5.0% of all head and neck tumors. Parotid gland tumors account for approximately 80.0% of all salivary gland tumors, most of which (75.0–80.0%) are benign [1]. Pleomorphic adenomas (PA) are the most common tumor of all parotid gland tumors, which are benign mixed tumors accounting for approximately 60.0% of all parotid tumors. Monomorphic adenoma (MA), unlike PA, is a type of benign parotid gland tumor that lacks the stromal cell line and is only composed of epithelial or myoepithelial components, including Warthin tumor (WT), basal cell adenoma (BCA), and oncocytoma [3]. WT is the second-most common benign tumor of the parotid gland, known as papillary cystadenoma lymphomatosum or adenolymphoma [4]. The occurrence of BCA is not that common, albeit it is the third-most common type of benign tumor representing approximately 1.0–3.0% of all salivary gland neoplasms [5]. PA has a higher tendency to become malignant relative to BCA and WT, which share a much lesser degree, whereas the other 8 types never develop malignancy [6, 7]

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