Immunoperoxidase staining in the detection of lymph node metastases in stage I breast cancer.

Axillary lymph node involvement by tumour metastasis is of major prognostic significance in breast carcinoma. In an immunocytochemical study using monoclonal antibodies to cytokeratins, 7 (23%) of 30 cases of node-negative breast carcinoma were found to contain metastases, resulting in upstaging of the disease. The metastatic foci were missed on routine screening of H&E stained sections. There was no significant association between the presence of metastases and the location, diameter, type or grade of the primary tumour. These findings emphasize the contribution of immunocytochemical staining for the identification and detection of metastatic breast carcinoma in axillary lymph nodes.