Regional Non-mass Enhancement (NME) on Breast MRI

IMAGING FINDINGS: ​
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Axial Maximum Intensity Projection (MIP) image of the breasts demonstrates regional non-mass enhancement occupying the majority of the medial right breast.
 
WHY IT MATTERS:

1. Non-mass enhancement can have several distributions. These include focal, linear, segmental, regional, diffuse or multiple regions.
2. Regional non-mass enhancement is defined as an area of enhancement that involves >25% of a quadrant and does not appear to conform to a ductal distribution. It can be due to normal hormonal variation, fibrocystic changes or extensive DCIS among other etiologies.​

FURTHER READING:
Patterns of Nonmasslike Enhancement at Screening Breast MR Imaging of High-Risk Premenopausal Women (RadioGraphics 2013)