A common pattern is a large dominant lesion with scattered smaller satellite lesions
Screening
In screened high-risk populations, new masses that develop over the course of surveillance have a likelihood of being HCC approaching 100%
Masses that have a typical appearance of hemangioma have a 50% chance of being HCC
Pitfalls
In advanced cirrhosis the diffuse hepatic inhomogeneity and nodularity both reduce the sensitivity of sonography to as low as 50%
Therefore better to start screening early in disease course
large tumors that involve liver segments diffusely are often harder to detect with sonography than are smaller tumors
Tumor thrombus
HCC is the tumor most likely to invade the portal vein
May see continuity between parenchymal tumor and tumor thrombus
Blood flow within the thrombus is highly specific for tumor thrombus
Tumor invades portal vein peripherally and grows toward the central veins so arterial flow to the tumor is in the opposite direction from the normal hepatic artery flow
Portal vein expansion by the thrombus suggests that it is a tumor even if no detectable tumor vascularity