Update on classification, diagnosis and management of columnar cell lesions of the breast

Columnar cell lesions (CCLs) are clonal alterations of the terminal duct lobular unit (TDLU) characterised by enlarged, variably dilated acini lined by columnar epithelial cells. They encompass a spectrum of morphological changes ranging from columnar cell change to columnar cell hyperplasia with or without atypia. With the increasing uptake of the breast cancer screening programme and wider use of mammography, more and more of these lesions are identified with associated calcifications, leading to an increasing number of biopsies being obtained that show these changes. In this review, we describe the historic concepts behind the evolution of the terminology of CCLs, and give an update on the diagnostic criteria, immunohistochemistry, and molecular genetics of these lesions. Their relation to breast carcinoma and current management strategies are also discussed. With the relatively recent classification scheme for these lesions, the recognition and study of CCLs is more standardised, and the role of these lesions as potential breast cancer risk factors will become more evident.