Aim: This study aims to conduct a systematic review of the current knowledge regarding the diagnostic performance of MRI in the investigation of non-mass lesions of the breast. Method: Up to July 2022, PubMed, Scopus, Web of Science, and Embase were searched comprehensively. All studies examining the diagnostic performance of MRI in non-mass lesions were included except review articles, articles published in a language other than English, and case reports or series of cases. Two independent reviewers performed a literature review and data extraction. A checklist for cross-sectional studies developed by the Joanna Briggs Institute (JBI) was used to assess sources of bias. Results: The systematic review included two studies. If any enhancement is present on MRI, most ultrasound NMLs exhibit a non-mass-enhancement. We found that the distribution of non-mass enhancement lesions was primarily segmental and regional. The highest number of malignancies is associated with segmental distributions since 81.8% of the cases with segmental enhancement were ductal carcinomas, specifically DCIS. Conclusion: Non-mass lesions of the US that do not enhance in MRI have a good prognosis. Breast cancer is very unlikely in these cases, so follow-up is acceptable unless there is a suspicion of malignancy on mammography. In cases where regional and segmental enhancement of NMLs occurs on CE-MRI, ductal carcinomas may be present, and a pathological examination is warranted. [ABSTRACT FROM AUTHOR]