Cellular stromal reaction in lymph node metastases of human colorectal carcinomas.

The composition and extent of lymphoreticular infiltrates in 19 lymph node metastases of 15 cases of colorectal cancer (Dukes stage C) were investigated histologically and immunohistologically. The cellular stromal reaction in the lymph node metastases showed a clear predominance of monocytes/macrophages (considered important components of the host's natural defence system) and of T lymphocytes and their major subsets (essentially maintaining the cell-mediated system of immune surveillance). Cells involved in the humoral immune response (B lymphocytes, plasma cells and B-accessory reticulum cells) and other components of natural resistance (natural killer cells, tissue mast cells and eosinophilic granulocytes) were usually found only in small amounts. It should be emphasized that an in situ histomorphological study allows only limited conclusions to be drawn about the functional properties of the cells. However, the preferentially intrastromal localization of the lymphoreticular infiltrates obviously militates against intense host-tumor interaction.