Focal breast edema associated with malignancy on T2-weighted images of breast MRI: peritumoral edema, prepectoral edema, and subcutaneous edema.

Edema, defined as high signal intensity on T2-weighted images, is a useful breast MRI finding, which compensates for the moderate specificity of breast MRI. Although diffuse breast edema can be caused by benign and malignant etiologies, focal edema is commonly associated with malignancy except for previous procedures including biopsy and surgery. For more accurate comprehension of the appropriate usage of breast edema, focal breast edema should be divided into three different types: peritumoral edema, prepectoral edema, and subcutaneous edema. It is useful to review and clarify these types of focal breast edema based on pathological findings as this may help predict the likelihood of malignancy in breast MRI lesions.