Regional lymph nodes and hematogenous metastasis of cancer

Aim. Morphological study of the microvasculature of regional lymph nodes in relation to the cancer of the lymph nodes as possible additional or alternative metastasis pathways. Methods. The lymph nodes of 150 cancer patients (1263 nodes in total), regional to cancer of various localization, were studied. Histological sections staining with hematoxylin and eosin by Van-Giesons method, pyronine by Brachets method, toluidine blue and picro-Mallory were prepared. An immunohistochemical study was performed using monoclonal antibodies to pan-cytokeratins, CD31, type IV collagen, CD3, CD20, and CD68. The area of metastases to the lymph nodes was determined by using a morphometric grid and used to identify the four study groups. In addition, the immunomorphological reactions of the lymph nodes were taken into account in each group. Results. It was identified that the microvasculature of the lymph nodes can be involved in the metastatic process along with the lymphatic pathways. At the same time, there is a decrease in vascular wall function and violation of the rheological properties of blood, accompanied by the deposition of intra- and extravascular fibrin. Hematogenous metastasis is largely influenced by the state of lymph node sinuses, in which blood is found, and in some observations by the expression of CD31 (a marker of blood endothelium). Hematogenous dissemination of cancer often begins after the appearance of lymph node metastases. The greater the anatomical extent of lymph node metastases, the more often tumor cells are present in the blood vessels. In addition, an isolated lesion of the microvasculature with the presence of tumor cells in the extranodal vessels without metastases in the lymph node itself was revealed. It was observed that the invasion of tumor cells into the microvasculature depended on the immunomorphological reactions of the lymph nodes. Conclusion. The microvasculature of regional lymph nodes can be both an additional and an alternative lymphogenous metastasis pathway of cancer; at the same time, vascular invasion is accompanied by microcirculation disorders and depends on the volume of metastases and the immunomorphological reactions of the lymph nodes.