Reactive changes in lymph-nodes draining breast-carcinoma and their relation to tumor spread.

The changes in anatomical structure and functional composition found in lymph nodes draining breast carcinoma are commonly termed 'reactive'. These features are described in relation to nodal tumour growth. The nodes studied showed increasing structural complexity with increasing size. Capsular infolding, with subsequent nodal segmentation was prominent. Their composition differed from the generally accepted proliferative pattern in that massive T-cell activity was often directly subcapsular. This may represent a local immunological response in nodes that are otherwise unstimulated. They were found in both the presence and absence of nodal tumour. In tumour-bearing nodes anatomical changes involved gross modification of the pathways available for tumour spread. In some this restricted tumour growth to certain nodal segments, but in others it provided short cuts through the nodes to the efferent draining vessels, potentially increasing the possibility of distant spread. The anatomical changes resulting from the 'reactive changes' in the lymphoid cell populations are thus not irrelevant to tumour spread, although the possible immunological significance of the latter are as yet unknown.