Abstract
For examining the pathway of hepatic metastasis of gastointestinal cancer, we established rat models of simple mesenteric lymphagiectomy and mesenteric lymph vessel obstruction. With these models, we carried out mesenteric lymphangiography and examined them for morphological changes in lymph vessels and lymph flow. In the model of simple mesenteric lymphagiectomy, the contrast material filled the intestinal lymph trunks and the thoracic duct in 3 of 5 animals on the 4th postoperative day and in all 5 animals on the 6th postoperative day, indicating lymph vessel recanalization. In the model of lymph vessel obstruction, we carried out mesenteric lymphangiography on the 6th postoperative day and obtained images of the mesenteric vein, the portal vein and the liver in all 5 animals. These images revealed lyphatico-venous communication induced by the mesenteric lymph vessel obstruction. In clinical cases of multiple hepatic metastasis of colonic cancer, carbonic particles injected into the paracolic lymph node were immediately detected in the portal blood. The lymphatico-venous communication is considered to be induced by lymph vessel obstruction, lymph retention and elevation of endolymphatic pressure. The presence of lymphatico-venous communication could be an important factor in the mechanism of hepatic metastasis of gastrointestinal cancer. This communication suggests the possibility of hematogenous metastasis via the lymphatic system.
