The largest and progressively increasing changes occur in the regional lymphatic collectors of the lungs in cancer. The relationship of the growing tumor in the lung with the regional lymphatic apparatus is very peculiar. This is determined by the reaction of all components of the lymphatic collectors both to the waste products and decay of the cancerous tumor, and to the formation and development of its metastases here. The latter cause blockade, destruction of the lymphatic capillaries, blood vessels, nodes and induce the formation of compensatory pathways of lymph outflow. Ultimately, destructive changes due to the high malignancy and transience of the pathological process prevail. At the same time, a significant and even total lesion develops, both regionally and closely related sections of the lymphatic collectors associated with them, resulting in the generalization of the tumor process.
In the initial period of the development of the disease, changes in the lymphatic system in lung cancer are manifested in the expansion of the lymphatic vessels, especially in the interlobar cracks and in the basal parts of the corresponding lobes. Around the tumor, a dense network of lymphatic vessels forms, with the appearance of peculiar deformations and irregularities in the contours. Nastenia develops polypoid outgrowths directed toward the tumor and merging with each other, forming new capillaries. At the same time, in the central parts of the growing tumor, over time, they become small, with destroyed, ulcerated edges. In the more peripheral ones, they still retain their structure, often represented by abundant reticular anastomoses, the loops of which for the most part are not yet closed and are only being formed. With the progression of the disease, destructive processes in both the pre-existing and newly formed lymphatic networks, destructive processes always prevail: there is a deformation of the lymphatic capillaries and
vessels, the development on their walls of numerous bizarre outgrowths. These changes are growing: the contours of blood vessels become even more uneven, their lumen is narrowed in places. Where the pleura is adjacent to the tumor, the loops of the lymphatic network of an irregular shape are often not closed, and the contours of the vessels look fuzzy, with notches. At this time, there is still no complete blockage of lymph outflow, but signs of lymphostasis are already beginning to appear. Subsequently, as the tumor grows, destruction and degeneration of the lymphatic network, which is in close proximity to it, occurs with the development of new capillaries and blood vessels in more distant parts of the lung. Here, the lymphatic capillaries expand compensatoryly, form finger-shaped outgrowths and form a dense network with the formation of additional pathways of lymph outflow.
Noticeable changes occur in lung cancer in the lymph nodes. They are associated both with the defeat of the lymph nodes by metastases or direct growth of the tumor in them, and with the impact on the lymphoid tissue of its metabolic products.
The most frequently observed increase in the size of regional lymph nodes. Meanwhile, it is well known that not all enlarged lymph nodes contain cancer metastases. During the histological study of most of the enlarged nodes, pronounced lymphoid and reticular hyperplasia is noted to varying degrees, as a kind of reaction to the various metabolic processes in a growing tumor, as well as the inflammatory, paracancrotic process in the lung tissue that accompanies it. It is possible that a peculiar protective reaction of the regional lymphatic apparatus manifests itself in this way . It was found that changes in the lymph nodes not affected by tumor metastases are expressed in a kind of hyperplastic reaction of the reticular cells of the sinuses of the node. In these cases, they expand, occupying the cortical part of the lymph node, and their lumen is filled with hyperplastic reticular cells, which partially transform into fibroblasts with the formation around collagen. These changes are recognized as pathognomonic and are designated as “sinus histiocytosis”. It was noted that in patients with a high degree of “sinus histiocytosis” in the regional lymph nodes, the spread of metastases and the progression of the primary tumor in the lung are less pronounced, and the life expectancy after surgery is much higher.