Ultrasound Features as Adjunctive Predictors of Pathological Grade in Phyllodes Tumors of the Breast: An Imaging‐Pathology Correlation Study

Abstract

ABSTRACT Background and Aim Phyllodes tumors of the breast are rare fibroepithelial neoplasms whose pathological classification remains challenging due to marked histological heterogeneity, often complicating clinical management decisions. This study investigated whether preoperative ultrasound features correlate with pathological grade in phyllodes tumors and can serve as adjunctive information to guide diagnosis and management. Methods This retrospective study included 78 patients with pathologically confirmed phyllodes tumors (55 benign, 22 borderline, 1 malignant) who underwent preoperative ultrasound. Two blinded breast radiologists assessed tumor characteristics using the BI‐RADS lexicon. Histopathological grading followed the 2019 WHO criteria. Statistical analysis included chi‐square tests, receiver operating characteristic (ROC) curve analysis, and interobserver agreement assessment. Minimum follow‐up was 12 months (median, 28 months; range, 12–48 months). Results Significant differences between benign and borderline tumors were observed for maximum diameter (median, 2.7 vs. 5.0 cm; p < 0.001), irregular shape (21.8% vs. 72.7%; p < 0.001), wavy margins (18.2% vs. 72.7%; p < 0.001), calcification (16.4% vs. 50.0%; p = 0.004), and internal anechoic/hypoechoic areas (1.8% vs. 77.3%; p < 0.001). Boundary characteristics, aspect ratio, orientation, and color Doppler flow were not discriminatory ( p > 0.05). The optimal size cutoff was 3.55 cm (AUC: 0.881; sensitivity: 82.6%; specificity: 83.6%; p < 0.001), while a combined model incorporating all five features achieved superior performance (AUC: 0.924; sensitivity: 90.9%; specificity: 85.5%). The single malignant tumor measured 18 cm and demonstrated all high‐risk features. Local recurrence occurred in 9.1% of borderline tumors (2/22), and no benign tumors recurred during follow‐up. Interobserver agreement ranged from moderate to almost perfect ( κ = 0.58–0.89). Conclusion Specific ultrasound features, particularly size > 3.55 cm, irregular shape, wavy margins, calcification, and internal cystic areas, correlate significantly with borderline grade in phyllodes tumors. These findings can guide clinical suspicion, prompt consideration of wider excision when wavy margins are present, and help pathologists target solid components adjacent to cystic areas, potentially improving diagnostic accuracy and reducing recurrence.