Missed nodal metastases in breast-cancer.

The routine use of immunohistochemistry has been suggested in the examination of the axillary nodes from patients with node-negative breast cancer in order to detect possible micrometastases. In this study, comprising 70 axillary specimens, we found missed micrometastases in 5 lymph nodes from a total of 40 cases following staining with epithelial membrane antigen. These metastases were also visible in the original haematoxylin and eosin stained slides, but missed on first examination. This makes a total of 10% of the cases, but only 0.8% of the nodes examined. Due to the increased expense of immunohistochemistry we would not recommend it as a routine in the examination of the axillary specimens. Until the prognostic significance of such deposits has been clearly defined we recommend hilar sectioning of the nodes, i.e. targeting of the sites of choice for micrometastases, and a second look at the slides from 'node-negative' cases, before they are reported.