Cytologic diagnosis of columnar-cell lesions of the breast

This study describes the cytologic features of breast columnar-cell lesions (CCLs) and determines whether these lesions can be diagnosed by fine-needle aspiration. We present ten cases of biopsy-proven CCL with prior fine-needle aspiration material and discuss the spectrum of changes, as well as features important in the cytologic distinction of CCL from diagnostic mimics. CCLs were characterized by flat sheets of cells with enlarged nuclei, distinct cell borders, and finely granular cytoplasm. Cytologic atypia ranged from minimal to severe, and many cases (8/10) exhibited a paucity of myoepithelial cells. CCL showed significant cytologic overlap with papillary neoplasms and well-differentiated adenocarcinomas. The prospective diagnosis of CCL cannot reliably be made by fine-needle aspiration. However, it is important to recognize the range of cytologic atypia that can be seen with CCL to avoid an overdiagnosis of malignancy.