To list the MRI features of non mass like enhancement.

To list the differential diagnoses of non mass like enhancement.

To list the management pathway for non mass like enhancement.

In non mass like enhancement, the main differential diagnosis is DCIS versus so called “mastopathic changes”.

Since DCIS is a differential diagnostic considération, enhancement kinetics are unreliable to categorize non mass like enhancement.

Symmetry and configuration are the key imaging features.

Non mass like enhancement is a fréquent finding in breast MRI. It relates to the fact that enhancement occurs in the normal-appearing fibroglandular tissue that surpasses that of the other parts of the parenchyma. There is no associated space occupying lésion. In pre-contrast non-fat-suppressed or fat-suppressed Tl-and T2-weighted images, there is usually no correlate observable. The differential diagnosis of non-mass-like enhancement is between benign nonspecific fibrocystic disease / adenosis, hormonal stimulation, and subclinical mastitis on one hand, versus DCIS or (less likely) diffusely infiltrating (usually lobular) cancer on the other. Key components of differential diagnosis is configuration of the enhancement (does it follow the orientation of the milk duct or not?) and symmetry (symmetric or asymmetric). Less important criteria are internai enhancement (internai architecture) and enhancement kinetics. It is important to realize that enhancement kinetics can only be used to corroborate the suspicion of DCIS - but they can not be used to alleviate the indication to biopsy a finding which, based on configuration and asymmetry, is suspicious. Management dépends on the différent constellation of clinical, mammographie, and MRI findings. It usually includes short-term follow up (6 months) and, if stable/persistent, MR guided vacuum biopsy.