Hepatocellular adenoma: the molecular subtypes and their risks
- Lesion
Hepatocellular adenoma is a benign liver tumour, mostly in young women on hormones; some types bleed or turn into cancer.
What it is
Hepatocellular adenoma is a benign neoplasm of hepatocytes that usually arises in a normal liver, classically in young women using oral contraceptives, and also with anabolic steroids, obesity and glycogen storage disease. It is now classified by molecular subtype, which predicts risk: inflammatory and HNF1A-inactivated types are most common, while β-catenin-activated adenomas carry the highest risk of hepatocellular carcinoma. Large adenomas can rupture and bleed into the abdomen.
Structure
- Gross: well-demarcated pale or yellow-tan nodule, sometimes with hemorrhage, up to many centimetres, often under the capsule.
- Micro: sheets and cords of hepatocytes in plates one to two cells thick, isolated thick arteries, no portal tracts or bile ducts.
Molecular subtypes of hepatocellular adenoma
| Subtype | Molecular change | Features and stains | Main risk |
|---|---|---|---|
| HNF1A-inactivated | Loss of HNF1A (somatic or germline) | Steatotic; loss of LFABP staining | Low malignancy risk |
| Inflammatory | Activating gp130 (IL6ST) or other JAK-STAT mutations | Sinusoidal dilation, inflammation, thick arteries; SAA and CRP positive | Bleeding; some also carry β-catenin mutation |
| β-catenin-activated | CTNNB1 (or other Wnt pathway) activation | Cell atypia; nuclear β-catenin, diffuse glutamine synthetase | Highest risk of HCC |
| Sonic hedgehog | GLI1 fusion genes | Often hemorrhagic | Bleeding |
Markers
- LFABP
- Serum amyloid A
- C-reactive protein
- β-catenin (nuclear)
- Glutamine synthetase
Clinical notes
- Pain or sudden intra-abdominal bleeding, especially in pregnancy; many are incidental.
- Resection is advised for β-catenin-activated tumours, lesions of five centimetres or more and adenomas in men.
Test yourself
Think of the answer, then tap the question to see it.
Which subtype of hepatocellular adenoma has the highest risk of becoming carcinoma?
The β-catenin-activated subtype, which shows nuclear β-catenin and diffuse glutamine synthetase staining.
Why does an adenoma lack portal tracts?
It is a neoplasm of hepatocytes alone, fed by isolated arteries, without normal portal tracts or bile ducts.
Which hormone exposures are linked to hepatocellular adenoma?
Oral contraceptives in women and anabolic androgenic steroids.
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Primary Liver Cancer Treatment (PDQ®) - NCI (National Cancer Institute, 2026).
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Representative model, for educational purposes only.