Diagnostic Accuracy of Breast Ultrasonography Parameters in Idiopathic Granulomatous Mastitis Patients: a Cross-Sectional Study.

Background: Idiopathic granulomatous mastitis (IGM) is a rare inflammatory breast condition. Accurate diagnosis is crucial for effective management. The present study aimed to evaluate the diagnostic accuracy of breast ultrasonography (US) parameters in IGM patients. Methods: This cross-sectional study enrolled patients with IGM. Patients were first assessed by their pathology as a reference test, immediately followed by the breast US as an index test. The binary data of breast US parameters (parenchymal heterogeneity, irregular lesion border, axillary lymphadenopathy, fistula, hyperkeratosis and well-defined heterogeneous lesion) was assessed and reported with diagnostic parameters. Results: Finally, 140 patients were enrolled in this study. Key US parameters for diagnostic accuracy were identified: irregular lesion border (sensitivity: 81.8%, specificity: 62.5%), fistula (predicitive positive value: 100%) and hyperkeratosis (predicitive positive value: 100%). Axillary lymphadenopathy and parenchymal Heterogeneity showed lower diagnostic value. The optimal ultrasound score cut-point was 1.5, with a Youden index of 0.81, sensitivity of 0.81, and specificity of 1.00. The area under the ROC curve was 0.95. Conclusion: This study highlights the importance of specific US parameters in diagnosing IGM, providing valuable insights for clinicians and radiologists.