The clinical significance of cytokeratin-positive cells in lymph nodes at the time of mastectomy from patients with ductal carcinoma-in-situ

Background: We determined the presence or absence of and clinical significance of cytokeratin-positive cells in the lymph nodes of patients who had had mastectomies for ductal carcinoma-in-situ. Methods: Two pathologists independently assessed the axillary lymph nodes found. All patients had either a core or open biopsy performed before the time of mastectomy. The lymph nodes were assessed with hematoxylin and eosin stain and immunohistochemistry for cytokeratin marker AE1/AE3. The slides were assessed for the presence or absence of epithelial cells. As a control, axillary lymph nodes found in prophylactic mastectomies were assessed. None of these had had a previous biopsy performed. Results: Lymph nodes from all patients demonstrated no obvious epithelial cells on hematoxylin and eosin stain. Peripheral sinuses of lymph nodes from six patients (23%) who had mastectomies for ductal carcinoma-in-situ contained a few cytokeratin-positive cells on immunohistochemistry. The lymph nodes of the control group demonstrated no cytokeratin-positive cells. The mean follow-up of patients was 5 years, and all patients were alive without recurrence at the time of the study. Conclusions: Epithelial cells may be present in the lymph nodes draining a site of recent breast biopsy in the absence of invasive carcinoma, indicating that these are an artifact of recent surgery and not of micrometastatic disease.