Early and Most Common Metastasis Pathway of Primary Liver Cancer

The earliest and most common way for primary liver cancer to spread is through hematogenous metastasis within the liver. Hematogenous metastasis occurs when cancer cells from the primary tumor enter the bloodstream and travel to various organs such as the lungs, liver, bones, and brain, where they establish secondary tumors. In the case of liver cancer, these cancer cells can invade the portal vein and form tumor thrombi. When these thrombi break loose, they can lead to multiple metastatic lesions within the liver.

Tumor thrombi in the main portal vein can cause obstruction, leading to portal hypertension and refractory ascites. Hematogenous metastasis can also spread to distant sites such as the lungs, adrenal glands, bones, pleura, and brain, causing symptoms specific to those areas. Pleural metastasis is more commonly seen on the right side and may result in pleural effusion.

Besides hematogenous spread, liver cancer can also metastasize through lymphatic channels and direct seeding. Lymphatic metastasis is relatively common, with the most frequent site being the lymph nodes around the hepatic hilum. Cancer cells can also reach the lymph nodes near the pancreas, spleen, aorta, or even the supraclavicular lymph nodes.

The least common type of metastasis is peritoneal seeding, where cancer cells detach from the liver and implant onto the peritoneum or pleura. This can lead to the development of hemorrhagic ascites or pleural effusion.

Understanding these different pathways of metastasis is crucial for early detection and effective treatment planning for patients with primary liver cancer.