Diagnosis and Management of Focal Nodular Hyperplasia
What Is Focal Nodular Hyperplasia?
Focal nodular hyperplasia (FNH) is a solid, benign hepatic mass of non-vascular origin and is the second most common benign liver lesion. FNH lesions can occur alone or in conjunction with other lesions like hemangiomas.
The pathology of FNH is described below
Laboratory Features: Normal Alpha-fetoprotein
Imaging Techniques: Spokes of wheel vascular pattern.
Histopathological Features: Central scar, ductular reaction, and fibrosis
Gene Expression: Beta-catenin pathway activation
Diagnosis of FNH
The diagnosis of FNH consists of imaging techniques. There must be characteristic features of FNH lesions and these lesions should not resemble other similar lesions.
In FNH, the levels of Alpha-fetoprotein remained within the reference ranges.
In FNH, the levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (GGT) displayed minor elevations. Sometimes the increase in these levels may be associated with other comorbid conditions and during a diagnosis this has to be taken into consideration.
Ultrasonography, Credits: pixabay
To evaluate liver lesions including FNH, ultrasonography was considered the first imaging modality. But this technique lacks an appropriate sensitivity.
FNH often appears as an isoechoic or hypoechoic mass with a hyperechoic central scar relative to the liver parenchyma.
In some countries, Contrast-enhanced ultrasonography is used to differentiate FNH and hepatocellular adenoma.
Computed Tomography,Credits: pixabay
Triphasic helical computed tomography with and without contrast is a cheap and reliable imaging modality.
Pre-contrast, focal nodular hyperplasia appears hypodense or isodense with a central scar evident in approximately one-third of cases.
FNH appears hyperdense during the hepatic arterial phase and isodense during the portal venous phase rendering the lesion indistinguishable from the rest of the liver parenchyma.
Magnetic Resonance Imaging
MRI, Credits: pixabay
MRI shows the highest sensitivity (∼70%) and specificity (98–100%) for FNH.
MRI reliably allows for discrimination between FNH and other focal liver lesions in most cases.
FNH lesions in an MRI imaging appear isointense to hypointense lesions.
MRI combined with hepatobiliary scintigraphy is the best test to diagnose focal nodular hyperplasia and the sensitivity and specificity of this technique are 99% and 100% respectively.
Doppler US and the contrast-enhanced US (CEUS) can greatly improve the accuracy in the diagnosis of FNH.
Management of FNH
As FNH may sometimes be difficult to diagnose, the healthcare professional team need to remain careful when making a diagnosis.
A comprehensive evaluation of a patient by physicians, nurses, pharmacists, and other healthcare professionals is necessary, before carrying out any surgical intervention.
If the patients have no symptoms, it is ideal to wait and make a diagnosis after some time.
Patients presenting with symptoms may need surgical resection.
If the patient is suspected to have FNH, contrast-enhanced MRI is done. If the diagnosis is doubtful, CEUS and biopsy are performed. Diagnosis is made based on the size of lesions.