Neovasculature of benign thrombus of the inferior vena cava demonstrated by computed tomography during hepatic arteriography, mimicking a small hepatocellular carcinoma.

A 64-year-old man who underwent hepatectomy for hepatocellular carcinoma (HCC) 4 years ago followed by transarterial chemoembolization for recurrent foci 1 year later had a thrombus in the inferior vena cava (IVC). Tumor thrombus derived from HCC was suspected owing to the increase in size and hepatic arteriography was performed. Common hepatic arteriography demonstrated a small stain suggesting a recurrent HCC in the remnant liver. However, CT during hepatic arteriography revealed that the stain localized not in the liver but within the thrombus in the IVC; there was no recurrent HCC in the liver. The dense stain associated with thin neovasculature developed through the thrombus was recognized. The thrombus spontaneously regressed 8 months later. It was speculated that the neovasculature played an important role in a process of absorption of the thrombus. One should note that the stain shown on angiography does not always suggest that the lesion is localized in the liver and is malignant.