Section: Hepatobiliary Sub-section: Liver Curriculum: Curriculum, page 86
Definition
Benign epithelial tumour comprised of hyperplastic hepatocytes
Epidemiology
- 2nd most common benign solid liver tumour.
- Prevalance 0.2%.
- Mostly female
- 20-40yrs.
Risk factors
- Treatment for childhood cancer w haematopoietic stem cell transplantation
- ?female hormones
- No clear relationship with OCP
Aetiology/Pathology
- Injury to the portal tract
- Results in enlargement of arterial venous shunts
- Causes hyperperfusion in local arteries resulting in oxidative stress that triggers a response from hepatic stellate cells to produce the typical central scar
Pathology
- Lobulated lesion composed of nodules surrounded by fibrous septa originating from central scar.
- On histological analysis, a classic FNH shows nodular hyperplastic parenchyma
- Development of FNH thought to be caused by injury to portal tract resulting in formation and enlargement of arterial to venous shunts.
- This causes hyperperfusion in local arteries resulting in oxidative stress triggering hepatic stellate cells to produce typical central scar.
Clinical
- Asymptomatic, incidental.
- Some have abdominal pain or palpable mass.
- Complications such as rupture causing intraperitoneal haemorrhage are rare.
Investigations
- USS
- Iso-echoic with central scar. Poorly able to differentiate
- CT
- Pre con: hypo or Iso
- Arterial: Homogenous and rapid diffuse centrifugal filling, central scar nonenhanced
- PV: slightly hyperattenuating or isoattenuating to liver and poorly visualised in many studies, the central scar remains hypodense.
- Delayed: hyperattentuation of central scar and septae.
- MRI
- T1 iso or hypo, hypointense central scar
- T2 hyperintense central scar
- Arterial - homogeneous enhancement
Management and follow up
- Usually dx on MRI or CT. Not routine biopsy unless uncertain dx.
- FNH not premalignant.
Unclear diagnosis
- Follow up imaging +/- biopsy
Asymptomatic
- No treatment
- No follow up
Symptomatic
- Further evaluation
If women on OCP
- f/u w annual USS 2-3 years in women on OCP.