Benign transport of breast epithelium into axillary lymph nodes after biopsy

The most important prognostic indicator of distant metastasis in breast can cer is histologic documentation of axillary lymph node metastasis. Controve rsy exists about the importance of micrometastases (<0.2 cm), and current p athology practice includes a careful search for their presence. We describe the histologic findings in a series of axillary lymph node dissections tak en approximately 2 weeks after breast biopsy. Each case has limited presenc e of epithelial cells in the subcapsular sinus of a draining lymph node tha t we attribute to mechanical transport of tumor and/or normal breast epithe lium secondary to the previous surgical or needle manipulation. These cells were accompanied by hemosiderin-laden macrophages and damaged RBCs. While the clinical implication of these findings is unknown, we believe that it w ill be of no clinical significance and have no untoward prognostic effect.