Abstract
OBJECTIVES: For lesions in the salivary glands, ultrasonography (US) is an ideal tool for initial assessment. The aim of this study was to characterize and differentiate between the Gray scale and Doppler US findings of intracapsular carcinoma ex pleomorphic adenoma (Ic-CxPA) and invasive carcinoma ex pleomorphic adenoma (Inv-CxPA). METHODS: A total of 87 patients (89 lesions) with histopathologically proven CxPA underwent US examination. The following characteristics were assessed on US images: size, shape, border, echogenicity, echo texture, posterior echo, vascularity, and regional lymph node enlargement. One-way analysis of variance (ANOVA), nonparametric test, Fisher's exact test, chi-square test and receiver operating characteristic (ROC) curve were used for the analyses of the US findings of Ic-CxPAs and Inv-CxPAs. RESULTS: We found that on US images, nearly all Ic-CxPAs (10/11) and a few of Inv-CxPAs (17/78) showed benign features, such as a regular shape, a well-defined border, and enhancement of posterior echo, while most Inv-CxPAs (61/78) showed one or more following features: an irregular shape, an ill-defined border, and lack of enhancement of posterior echo. CONCLUSIONS: Ic-CxPAs tended to exhibit benign features, whereas most Inv-CxPAs tended to exhibit one or more invasive features. US can provide strong evidence in differentiating Inv-CxPAs from Ic-CxPAs.