Portal vein thrombosis (PVT) can occur within the main portal vein, or it can occur in the branches of the portal vein within the liver itself. It can be an occluding thrombus or nonoccluding, with a clot present but continued blood flow through the vessel. The sequela of a long-standing PVT is cavernous formation of the portal vein, which represents bridging collaterals around the occlusion.