Abstract:

Objective: To assess the value of magnetic resonance imaging (MRI) in the differential diagnosis of benign papillary lesions with malignant papillary lesions of the breast. Methods: A retrospective analysis of breast MRI findings of 146 papillary lesions of the breast with pathologically confirmed diagnosis (106 benign lesions and 40 malignant lesions）was performed. The MRI findings were categorized according to MRI BI-RADS 2013 edition. Time-signal intensity curve(TIC） and apparent diffusion coefficient (ADC) map were obtained from the1.5 T Siemenseaera workstation. ROIs were drawn on ADC map of the slice with the largest tumor area using b=800 s/mm², avoiding necrotic or cystic parts. The early enhancement rate was measured within 1.5 min after injection. Results: In the mass cases, malignant lesions tended to appear more commonly in irregular shape than benign lesions （100.0% vs 62.2%）（P<0.05）. The margin of the benign lesions was circumscribed in 54.1%（40/74）, and the margin of the malignant lesions was spiculated in 56.3%（9/16）; 59.5% of the benign lesions were less than 1cm（44/74）, while 100.0% of the malignant lesions were between 1-5 cm（16/16）（P<0.05）. Benign lesions were presented as homogeneous-enhancement in 47.3% (35/74), and malignant lesions were presented as heterogeneous-enhancement in 75.0%（12/16）（P<0.001）. The papillary lesions of the breast tended to be locatedat periphery（benign 70.3% vs malignant 68.8%）. In the non-mass lesions, all the papillary lesions tended to appear in segmental distribution （benign 56.3% vs malignant 62.5%）. Diffuse distribution was more common in malignant papillary lesions（25.0% vs 6.3%）（P<0.05）, and focal distribution was more common in benign papillary lesions（37.5% vs 12.5%）（P>0.05）. Both benign and malignant lesions tended to present plateau and wash-out curves （71.7% vs 95.0%）. Malignant lesions were more commonly to be cystic (solid portion<25%) than benign lesions (10.0 % vs 0.9%). All the papillary lesions tended to be duct-dilated（62.3% vs75.0%）. The mean ADC value was lower in malignant lesions (0.95×10^-3 mm²/s vs 1.13×10^-3 mm²/s). Conclusions: The shape, margin, size, enhancement pattern of masslesions, distribution of non-mass lesions and ADC had diagnostic value for the differentiation of benign papillary lesions with malignant papillary lesions of the breast.

Key words: Magnetic resonance imaging, Diffusion weighted imaging, Papillary lesions of breast