Lymphatic metastasis

Lymphatic metastasis is the most common form of cancer metastasis. It refers to the phenomenon that invading tumor cells pass through the lymphatic vessel wall and are taken to the lymph nodes in the confluence area with the lymph fluid, and the same tumor grows at this center. Lymph node metastasis generally first arrives at the group of lymph nodes closest to the tumor, and then goes to the distant one in turn. When tumor cells infiltrate and grow at each station, they also spread to adjacent lymph nodes in the group. However, there are exceptions. In some patients, it is also possible to short-circuit the lymph nodes in the bypass path and transfer directly to distant lymph nodes. This method of transfer is clinically referred to as jumping transfer. These characteristics increase the complexity of tumor metastasis, which makes clinically appear some lymph node metastasis cancer which is difficult to find the original focus. There are generally two types of metastasis along the lymphatic vessels, namely continuous diffusion and discontinuous diffusion. Continuous spread refers to the progressive proliferation of gastric cancer cells in the lymphatic vessels, which continuously spread to the lymph nodes (or retrograde) along the lumen, reach a certain distance or reach the lymph nodes in the drainage area. Discontinuous spread refers to cancer cells falling into the lymphatic vessels without forming continuous cancerous cords, floating or swimming in the lumen of the lymphatics or swimming out of the lymphatic vessels in an amoebic motion, or It is the lymphatic flow that reaches the draining lymph nodes. The above two types of diffusion are not isolated, especially continuous diffusion in the lymphatic vessels, sometimes only reaching a certain distance, and then the cancer cells fall off into the lymphatic vessels, and then spread and metastasize in the second way. Metastatic lymph nodes are usually larger and harder than normal lymph nodes, and even a few fused together to form a huge mass. Most epithelial malignancies, such as various cancers, are prone to lymphatic metastasis. Because the lymphatic vessels are ultimately connected to blood vessels, malignant tumor cells can enter the veins along with the lymph fluid. Therefore, lymphatic metastasis eventually leads to bloodstream metastasis.