Gallbladder cancer metastasis pathway

Gallbladder cancer can spread in many ways, including direct invasion, lymphatic, hematogenous, along the neurovascular plexus, intraperitoneal implantation, and intrabiliary dissemination. Direct invasion (liver and surrounding organs) and lymphatic metastasis are the main ways of metastasis of gallbladder cancer. Among confirmed cases of gallbladder cancer, only about 25% of the tumors are confined to the gallbladder wall. 35% have local lymph node metastasis or invade adjacent organs such as the liver, and 40% have distant lymph node or organ metastasis.

1. Direct invasion accounts for 65%-90%. Because the gallbladder wall on one side of the gallbladder bed has no serosal layer, it is common for gallbladder cancer to directly invade the liver (segments IV and V) through the gallbladder bed. At the same time, because the gallbladder venous plexus directly flows back into the nearby liver, the tumor can directly invade the liver parenchyma along the vascular nerve plexus, and in the late stage, it can also cause distant metastasis in the liver or distant organ metastasis through the bloodstream. The tumor can directly invade the adjacent organs around the gallbladder (common bile duct, gastric antrum, duodenum, pancreas and transverse colon, etc.), or spread up and down along the hepatoduodenal ligament through the vascular nerve plexus, directly invade the extrahepatic bile duct or metastasis to the lymph nodes around the liver portal to compress the common bile duct and cause obstructive jaundice.

2. Lymph node metastasis accounts for 40%-85%. When the gallbladder muscle layer is affected, lymph node metastasis may occur. The pattern and range of lymph node metastasis of gallbladder cancer are consistent with the lymphatic drainage pathway of the gallbladder. The vast majority of lymph node metastasis first occurs in the bile duct lymph nodes, followed by the common bile duct lymph nodes and the liver portal lymph nodes, and finally metastasizes to other regional lymph nodes: peripancreatic, periduodenal, periportal vein, celiac trunk, and lymph nodes around the superior mesenteric artery. A few can retrogradely metastasize upward to the liver portal.

3. Hematogenous metastasis accounts for 20%-25%, returning to the quadratic lobe of the liver through the deep vein of the gallbladder, manifesting as a local mass in the liver near the primary lesion, with or without satellite nodules; lung metastasis is less common.

4. Spread along nerves accounts for 10%-15%. It can spread along the nerve plexus in the gallbladder wall or the hepatoduodenal ligament.

5. Spread into the bile duct is rare. The tumor descends along the gallbladder neck to the common bile duct and implants in the neck and the inner wall of the common bile duct. Cancerous tissue may also fall off and enter the common bile duct, causing obstructive jaundice.

6. Abdominal implantation is rare, but rupture or perforation of gallbladder cancer can lead to extensive abdominal implantation.