Differential Diagnosis for a Liver Lesion

The provided description of a well-demarcated 4cm lesion in segment 3 of the liver, which is heterogeneous and hyperintense on T2 weighted images, hypointense on T1 weighted images, with arterial enhancement and retained signal intensity in the portal venous phase, along with diffusion restriction, suggests several potential diagnoses. These can be categorized as follows:

• Single Most Likely Diagnosis

  • Hepatocellular carcinoma (HCC): This is the most likely diagnosis given the lesion's characteristics, particularly the arterial enhancement and the fact that it retains signal intensity in the portal venous phase, which is typical for HCC. The diffusion restriction also supports this diagnosis, as HCC often shows restricted diffusion due to its high cellularity.

• Other Likely Diagnoses

  • Focal nodular hyperplasia (FNH): Although less likely than HCC, FNH can present with similar imaging characteristics, including hyperintensity on T2 weighted images and arterial enhancement. However, FNH typically does not show significant diffusion restriction and often has a central scar.
  • Hepatic adenoma: These lesions can be heterogeneous and show arterial enhancement. However, they are usually more homogeneous on T2 weighted images and may not retain signal intensity in the portal venous phase as consistently as HCC.

• Do Not Miss Diagnoses

  • Metastasis: Although the imaging characteristics are not as typical for metastasis (which often shows more pronounced diffusion restriction and variable enhancement patterns), metastatic disease to the liver is common and can present in various ways. Missing this diagnosis could have significant implications for patient management and prognosis.
  • Intrahepatic cholangiocarcinoma (ICC): ICC can present as a mass-like lesion with similar imaging characteristics, including diffusion restriction. It is less common than HCC but is important not to miss due to its aggressive nature and different treatment approach.

• Rare Diagnoses

  • Hepatoblastoma: This is a rare liver tumor, mostly occurring in children, but can be considered in adults, especially if the lesion shows aggressive features and atypical imaging characteristics.
  • Inflammatory hepatocellular adenoma: A subtype of hepatic adenoma that can present with atypical imaging features, including significant heterogeneity and diffusion restriction, due to the presence of inflammatory cells.
  • Biliary cystadenoma/cystadenocarcinoma: These are rare cystic lesions of the liver that can show mural nodules and septal enhancement, along with diffusion restriction in solid components, but are less likely given the solid nature of the described lesion.