Extrahepatic Collateral Artery Supply to the Tumor Thrombi of Hepatocellular Carcinoma Invading Inferior Vena Cava: The Prevalence and Determinant Factors

Combined hepatic arterial and extrahepatic collateral supply for IVC tumor thrombi of HCC at initial presentation in a 48-year-old man. (a) On contrast medium–enhanced CT obtained in the arterial phase, the primary HCC shows a well enhancing tumor in the right posterior segment of the liver (arrowheads). (b) The tumor thrombi occupy more than half the IVC lumen and completely fill and distend the IVC lumen (arrow in the left image). The tumor thrombi also extend into the right atrium (arrow in the right image). (c) Celiac arteriography shows huge hypervascular tumor staining (arrowheads) and a thread-and-streaks sign (arrow) along the course of the right hepatic vein extending into the right atrium. In this patient, the left hepatic artery originates from the left gastric artery (not shown). (d) Right inferior phrenic arteriography shows primary tumor staining (arrowhead) and minor IVC tumor thrombi staining (arrow).

Exclusive extrahepatic collateral supply of IVC tumor thrombi is seen in a 49-year-old man with a history of chemoembolization. (a) On contrast medium–enhanced dynamic CT at initial presentation, the primary tumor in the right posterior segment of the liver shows typical findings of HCC: strong enhancement at the arterial phase and rapid washout at the portal phase. There is no evidence of IVC invasion. (b) After two sessions of chemoembolization, follow-up CT shows compact iodized oil uptake at the primary HCC. However, tumor thrombi appeared in the IVC (arrow). The route of invasion is considered to be the inferior right hepatic vein. (c) Celiac arteriography performed at the third chemoembolization session does not show residual tumor staining. (d) Right adrenal arteriography shows hypervascular staining of IVC tumor thrombi (arrow) around the original mass with iodized oil uptake (arrowheads). Therefore, the IVC tumor thrombi are exclusively supplied by the right adrenal artery. (e) Radiograph obtained after chemoembolization through the right adrenal artery shows homogenous uptake of iodized oil in the tumor thrombi (arrowheads). (f) After 9 months, follow-up CT demonstrates shrinkage of the IVC tumor thrombi (arrow) with dense accumulation of iodized oil.

Overall cumulative survival rates calculated from time of detection of IVC tumor thrombi.