Breast lesions with unknown malignant potential (B3) comprise a diverse range of diagnostic abnormalities that may be connected to atypia. Approximately 20–30% of these cases can have associated in situ or invasive cancer; thus these entities are often referred to as high-risk lesions as well. Traditionally, open excision of such lesions was preferred to avoid patients from the needless anxiety or excessive healthcare expenses. However, with advancements in the field of radiological interventions and imaging; there has been emergence of literature regarding minimally invasive procedures/techniques for management of high-risk lesions. Their potential upgradation rates with various types of biopsies and role of multidisciplinary discussions to approach these lesions have also been highlighted by many authors. Thus it becomes imperative for radiologists who interpret breast imaging, to familiarize themselves with B3 lesions, their upgradation rates, and role of imaging in their management. This chapter attempts to discuss these areas of interest along with current recommendations for B3 lesion management.