Hepatocellular adenoma (HCA) or liver cell adenoma

2nd most frequent hepatic tumor in young women after focal nodular hyperplasia (FNH)

Heterogeneous, hypervascular, hypo-/iso-/hyperechoic mass

Round or mildly lobulated, well-defined borders

Subcapsular right hepatic lobe (75%)

Complex heterogeneous mixed echogenicity mass

Hypoechoic halo of compressed liver tissue with multiple vessels

Larger lesions prone to intratumoral hemorrhage or rupture with intraperitoneal hemorrhage

Best imaging tool: Ultrasound for lesion detection, guiding biopsy, and monitoring size

Liver-specific MR contrast agents have high accuracy in distinguishing HCA from other liver lesions

Hemangioma

FNH

Hepatocellular carcinoma

Potential complications: ± hemorrhage, malignant degeneration

More common in younger women on oral contraceptive pill (OCP)

Definitive diagnosis and subtype with biopsy

Molecular classification (4 subtypes) helps determine prognosis and management

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  β-catenin-activated HCA : 10%

  
  
  
  
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    Prone to malignant degeneration

  
  
  
  
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  Inflammatory (I-HCA) : 40-50%

  
  
  
  
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    More common in women on OCP, obese, or metabolic syndrome

    
    
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    Greatest risk of hemorrhage (up to 30%)

    
    
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    Malignant degeneration: 5-10%

  
  
  
  
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  HNF-1α : 30-35%

  
  
  
  
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    More common in women on OCP

    
    
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    Often asymptomatic, lowest risk of malignant transformation

  
  
  
  
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  Unclassified HCA : 10%

Rule out other liver tumors with similar imaging features, such as HCC or FNH