Columnar cell lesions of the breast: mammographic findings with histopathologic correlation.

Because of advances in mammography and a concomitant rise in the number of breast biopsies being performed for mammographically detected abnormalities, increasing numbers of columnar cell lesions (CCLs) are being described by pathologists. However, these lesions can be challenging to manage, since their classification has changed over time and only limited research has been conducted regarding their clinical significance. CCLs may be characterized by a single layer of columnar cells (columnar cell change [CCC]), multiple layers with stratification and apical tufting (columnar cell hyperplasia [CCH]), or monomorphic cells with cytologic atypia (flat epithelial atypia [FEA]). The differentiation between CCC, CCH, and FEA is clinically significant: CCC and CCH are considered benign lesions, whereas FEA can be associated with, and even a precursor to, low-grade ductal carcinoma in situ and atypical ductal hyperplasia. Therefore, the identification of FEA at core biopsy should prompt excision of the remaining portion of the lesion. Copyright RSNA, 2007.