Hepatocellular carcinoma (HCC) has a way of invading local vasculature, in particular the portal vein. HCC can invade intra or extra hepatic segments of the PV. It is particularly important that you determine whether a PV thrombus is bland (ie. just blood) or malignant. A bland thrombus will not contraindicate liver transplantation, whereas a malignant thrombus is considered stage IV (metastatic) disease and liver transplantation cannot be considered.
In the image above left, notice the large, enhancing lesion that appears to include the right and left side of the liver. Beneath it, you can see a similarly enhancing lesion, the tumor thrombus. This is the key to diagnosis- enhancement of the thrombus. Bland thrombus should not enhance after contrast administration. The figure to the right also shows this extesive tumor thrombus.
Considerations for treatment (since transplantation cannot be performed) will include TACE or sorafenib as long as the patient has Child class A, compensated disease and good functional status.