Phyllodes tumour of the breast: Differentiation of histological grade by ultrasonography

Objectives: To retrospectively evaluate whether benign and aggressive phyllodes tumours have distinguishing ultrasonographic features. Methods: We searched the breast imaging database for patients with diagnoses of phyllodes tumours between 2003 and 2014. The imaging studies of eligible patients were retrospectively reviewed. Results: A total of 46 patients (all women; mean age, 41.1 years; range, 20-69 years) were enrolled in the study. The histological grades were benign in 67.4% (n = 31), borderline in 23.9% (n = 11), and malignant in 8.7% (n = 4) of patients. The mean long-axis diameter of the tumour was 3.1 cm (range, 0.7-6.9 cm) in benign tumours and 5.8 cm (range, 3.0-13.0 cm) in aggressive tumours. As compared with benign phyllodes tumours, aggressive tumours showed larger long-axis diameter (p = 0.01), more frequently irregular shape (60% vs. 3.2%), indistinct or microlobulated margins (66.7% vs. 25.8%), and complex cystic and solid echogenicity (46.7% vs. 0%). Benign phyllodes tumours more commonly showed heterogeneous echogenicity with small anechoic clefts (54.8% vs. 20.0%). Conclusion: Several sonographic findings including long-axis diameter, shape, margin, and echogenicity were helpful to differentiate benign and aggressive phyllodes tumours. Irregular shape was a strong, independent predictor of aggressive phyllodes tumours.