Massive portal vein tumor thrombus from colorectal cancer without any metastatic nodules in the liver parenchyma.

Metastatic lesions in the liver derived from colorectal cancer rarely invade the portal vein macroscopically. Portal vein tumor thrombus is commonly associated with hepatocellular carcinoma. Colorectal liver metastases are usually accompanied by microscopic tumor invasion into the intrahepatic portal vein, and the incidence of macroscopic tumor thrombus in the trunk of the portal vein is rare. Here, we provide unique appearance of metastatic colorectal cancer. To the best of our knowledge, macroscopically, the right portal vein filled with the tumor thrombus without any tumor in liver parenchyma has been quite rare.