Multiparametric ultrasonography, elastography, and the Milan System for reporting salivary gland cytopathology in the preoperative evaluation of major salivary gland tumors.

INTRODUCTION: High-resolution ultrasonography (US) is widely used to evaluate diseases of the major salivary glands. Previous studies on salivary gland US have focused primarily on qualitative descriptions and have often been limited by small sample sizes. This study aims to identify the most relevant US features for differentiating major salivary gland tumors within a large surgical cohort. METHODS: This retrospective observational study included 271 patients who underwent surgical resection of salivary gland tumors between August 2015 and December 2025. All patients received preoperative US and fine-needle aspiration and had definitive postoperative histopathological diagnoses. Sonographic characteristics, Doppler vascular patterns, elastography findings, and Milan cytological categories were analyzed and compared with histopathological diagnoses using chi-square, Fisher's exact, and Kruskal-Wallis tests, followed by multivariable logistic regression to identify independent predictors of malignancy. RESULTS: Among the 271 tumors, 231 (85.24%) were benign (predominantly pleomorphic adenoma [38.01%] and Warthin tumor [33.21%]) and 40 (14.76%) were malignant. On univariable analysis, malignancy was significantly associated with irregular or speculated shape, ill-defined margins, heterogeneous echotexture, calcifications, solid architecture, spotted or mixed vascularity, and higher real-time elastography (RTE) scores (all p < 0.05). After multivariable adjustment, heterogeneous echotexture (OR 3.78, 95% CI 1.31-10.92) and calcification (OR 14.84, 95% CI 2.67-82.50) remained independent predictors of malignancy, while oval (OR 0.10) and lobulated (OR 0.13) shapes were independently associated with a lower likelihood of malignancy. Pleomorphic adenomas exhibited the highest mean shear wave elastography (SWE) values, whereas Warthin tumors demonstrated lower stiffness and more frequent cystic architecture. Cytologically, the Milan System demonstrated favorable diagnostic performance. Comparing category IVa with categories V and VI yielded a sensitivity of 86.67% (95% CI, 69.5-100.0%), specificity of 98.84% (95% CI, 97.3-100.0%), and accuracy of 97.87% (95% CI, 95.8-99.9%). CONCLUSIONS: Conventional US features remain highly valuable for differentiating benign from malignant salivary gland tumors. Elastography provides complementary information regarding tissue stiffness and heterogeneity, while the Milan cytology system demonstrates excellent diagnostic reliability.