Atypical Breast Proliferative Lesions and Benign Breast Disease

  Management of atypical breast lesions continues to evolve. There is considerable controversy as to whether these entities represent risk factors for future breast cancer or whether they are instead precursor lesions.  A better understanding of the prognostic and therapeutic implications of each of these lesions is important for assessing subsequent breast cancer risk.  Risk assessment tools are available for screening high risk patients and understanding the utility and limitations of these tools is important for all clinicians involved in the care of patients. There have been significant advances in breast cancer screening in the last several year including breast tomosynthesis, automated breast ultrasound, molecular imaging, as well as accelerated breast MRI protocols. This has raised the question: Do women at risk for breast cancer need additional breast cancer screening using these newer imaging modalities?  In addition, with these advancesin imaging, can women with atypical proliferative lesions be observed rather than undergoing surgical excision as some suggest? The role of observation, surgical excision and even prophylactic mastectomy in women with atypical proliferative lesions continues to be debated; however there is data that can guide physicians in the management of these patients.  Pleomorphic Lobular carcinoma in-situ (PLCIS) is a distinct pathological entity within LCIS and there is no consensus regarding surgical margins or the need for adjuvant treatment to prevent recurrence.  Recently, ductal carcinoma in-situ (DCIS) has been the subject of much controversy: is it truly a cancer or is it instead a precursor lesion.  The traditional management of DCIS with lumpectomy and radiation is now being debated and recent data demonstrates that low grade DCIS can be managed with observation.  Clinical trials are now accruing patients with low and intermediate grade DCIS to observation and