Occult hepatocellular carcinoma in cirrhosis: value of ultrasound-guided biopsy of portal vein system thrombus.

We report two cases of occult hepatocellular carcinoma associated with alcoholic cirrhosis, in which the diagnosis of malignancy was respectively established by ultrasound-guided biopsy of umbilical vein and portal vein branch thrombus. When measurement of serum alpha-foetoprotein, and liver ultrasonography and/or computed tomography failed to clearly demonstrate hepatocellular carcinoma, the presence of a thrombosis of the portal vein system is highly suggestive of malignancy, which may be easily confirmed by venous biopsy.