Nodular Hyperplasia of
Dr. Ihab Samy
Surgical Oncology Dept.
National Cancer Institute-Cairo Unversity
Benign liver cell tumors (BLCT) are common and their clinical management
The differential diagnosis of liver tumors requires understanding of the
clinical and imaging features of the liver lesions.
FOCAL NODULAR HYPERPLASIA
This is the second most prevalent benign liver lesion (after hemangioma), with a woman
preponderance, in 80–90% of the cases, in third or fourth decade and a global incidence
of about 0.6–3% of the general population.
There is no identifiable etiologic factor. It is, however, associated with a condition
having local or systemic vascular anomalies.
The most accepted theory posits a congenital vascular malformation as the trigger
event; however, it is thought to arise as a result of larger-than-expected pre-existing
spider-like arterial structures with heterogeneous blood flow in the liver cellular
architecture, resulting a hyperplastic hepatocytic response
FNH is a benign idiopathic fleshy tumour of the liver, ten times more common
than adenoma and is found at any age but mainly in adults.
Most of the patients are not symptomatic and the diagnosis is made
incidentally during surgery, autopsy or imaging procedures for others
The liver function tests are normal.
Complications, as the rupture, bleeding or malignant transformation,
although rare, are described in literature
Tumour is more or less rounded, lobulated and well demarcated but not
encapsulated with a diameter ranging from one to several centimetres.
When the tumour is large, it may be painful.
Other symptoms described are loss of appetite, nausea, vomiting and weight
Usually occurs in non-cirrhotic livers.
A central fibrous scar with prominent arterial branches is typically observed
at the histological examination.
Some cases reported of FNH complications mention dilatation of intrahepatic
bile duct, compression of portal vein, compression of stomach, compression
of inferior vena cava, intra-tumor bleeding and intra-peritoneal rupture.
The diagnosis of FNH can be made using imaging techniques in 90% of cases in
The characteristic radiologic findings of FNH have been well documented, but
the exact distinction of FNH from other hypervascular hepatic tumors is not
easy, especially in cases of small lesions.
Contrast-enhanced ultrasonography (CEUS) is the first modality of
choice for FNH:FNH typically shows arterial increase enhancement,
very marked in the first few seconds.
Centrifugal (70%) or eccentric (30%) enhancement through one
afferent correspondingly situated arteries is a diagnostic pointer.
Recently in 2013, Wang et al. from the University of Guangzhou
(Republic of China) confirmed that the contrast-enhanced computed
tomography (CECT) have similar diagnostic performance for FNH and
CEUS should be the first imaging technique for the diagnosis of FNH.
Gadoxetic acid (Gd-EOB-DTPA, Primovist®, Bayer Schering Pharma AG, Berlin, Germany)
is a hepatocyte-specific magnetic resonance (MR) contrast agent that is increasingly
used for liver MR imaging.
Gadoxetic acid is actively taken up by hepatocytes and excreted along the bile duct and
It is known to be specific for the diagnosis of FNH, showing hyperintense or isointense
regions compared to the liver during the delayed hepatobiliary phase
On dynamic contrast-enhanced MR images, FNH usually shows homogeneous
enhancement during the arterial phase, compartmentalized by radiate fibrous
septae, arising from the nonenhancing central scar.
The central scar of FNH usually shows a high SI on T2WI and delayed
enhancement because it is mainly a vascular and inflammatory scar.
Management and Treatment of FNH
If the patient is female with typical FNH on imaging, normal liver tests and no
medical history of cancer, the diagnosis of FNH is considered and the biopsy is
If the patient is a male, biopsy is proposed. In the case of atypical FNH on
imaging biopsy is necessary.
FNH is often asymptomatic and the surgery is not indicated even if the lesion
However, the patients with a large lesions can to develop abdominal pain or
compression of adjacent structures and liver resection may be indicated.
Cherqui D,2008 published a short report on clinical management of benign
liver cell tumors and it is proposed for FNH monitoring by an MRI six and
twelve months, then MRI or CEUS each year for three years after then stop
ACG Clinical Guideline 2014 for FNH
An MRI or CT scan should be obtained to confirm a diagnosis of FNH. A liver
biopsy is not routinely indicated to confirm the diagnosis (strong
recommendation, low quality of evidence).
Pregnancy and the use of oral contraceptives or anabolic steroids are not
contraindicated in patients with FNH (conditional recommendation, low
quality of evidence).
Asymptomatic FNH does not require intervention (strong recommendation,
moderate quality of evidence).
Annual US for 2 – 3 years is prudent in women diagnosed with FNH who wish to
continue OCP use. Individuals with a firm diagnosis of FNH who are not using
OCP do not require follow-up imaging (conditional recommendation, low
quality of evidence).