Hepatocellular carcinoma

Imaging

• 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