| Abstract: |
In the most recent edition of the World Health Organization Classification of Breast Tumours columnar cell lesions are classified as those without atypia, i.e., columnar cell change and columnar cell hyperplasia, and those with atypia, i.e., flat epithelial atypia. Accumulating evidence over the last two decades has suggested that columnar cell lesions represent the earliest precursors in the low-grade breast neoplasia family and are commonly found in association with other members of this family such as lobular neoplasia, atypical ductal hyperplasia, low-grade ductal carcinoma in situ, and low-grade invasive carcinomas. Optimal management of flat epithelial atypia has been a matter of debate. Although traditionally excised due to concern for finding a higher risk lesion on surgical excision, a critical appraisal of more recent studies suggests that observation may be a reasonable approach for at least some patients. This chapter will review the clinico-pathologic features of columnar cell lesions, their molecular pathogenesis, and the data informing management considerations. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022. |
