Hepatocellular Adenoma

DEFINITION

Benign liver neoplasms strongly associated with oestrogen use.
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EPIDEMIOLOGY

Incidence

Uncommon, except 30-40x more common in OCP users

Age

Gender

Geographical distribution

Risk factors
Personal
OCP
- duration and dose associated.
i.e. oestrogens
Androgens and anabolic steroids
Predisposing conditions
Hemochromatosis, B-thalassemia, type I metabolic diseases, glycogen storage diseases, DM II.

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AETIOLOGY

Benign liver tumours
Can occur spontaneously or in association with above factors

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BIOLOGICAL BEHAVIOUR

Pathophysiology
Can contain large subcapsular vessels
Can be pedunculated, resulting in torsion and pain.
Micro = benign hepatocytes arranged in a trabecular patterns and thin vessels throughout.

Pathology
Typically solitary
- multifocal in 10-30%
- 'hepatic adenomatosis' is more than 10 lesions.
--> more likely to get symptoms and rupture, and abnormal hepatic function.
--> tend to be diffuse making resection difficult.

Natural history
Risk of malignant transformation is 10%;
- higher in men

Complications
As expand >5cm, risk of haemorrhage and infarction increase
High risk of spontaneous bleeding (20-40%).
- can lead to severe abdo pain, hemoperitoneum and hypovolaemia
- but this is rare unless anticoagulated.
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MANIFESTATIONS

Symptoms

Usually found asymptomic and incidentally when small
Larger lesions:
- pain
- sense of upper abdo fullness

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INVESTIGATIONS

Biochemistry

Can have abnormal GGT and ALP (us. if large)

Imaging
CT
Hypervascular on arterial phase, become isodense or hypodense on portal venous phase (due to AV shunting)
Smooth surface, capsule and necrosis / haemorrhage help differentiate from FNH.
Can contain fat and may have calcification.
While imaging can helpfully distinguish adenoma from FNH, harder to distinguish from HCC
- except that HCC tends to have more classical / pronounced washout on portal venous phase imaging
MRI
Useful to differentiate from FNH
Hyperintense or isointense on T1
Mildly hyperintense on T2
Signal heterogeneity is one of the most consistent features
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MANAGEMENT

Conservative
If <3cm, observe with serial imaging and alpha-fetoprotein.
Stop OCP.

Operative
Resect to relieve symptoms, prevent bleeding or stop malignant transformation.
If >4cm strongly advise resection.
Anatomic or segmental resection.
Wide margins unnecessary as most are benign.
May need a staged resection if bilobar disease.
Ruptured

Delay surgery and stabilize; operative mortality 8%
Selective arterial embolization and then elective resection.


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REFERENCES
Cameron 10th