From the Guidelines
Idiopathic Noncirrhotic Portal Hypertension (INCPH) is characterized by histological findings of phlebosclerosis, nodular regeneration, sinusoidal dilatation, para-portal shunt vessels, and perisinusoidal fibrosis, as noted in the EASL clinical practice guidelines 1. The most prevalent histological features observed in INCPH patients include obliterative vascular lesions, which are thought to be the primary cause of the intrahepatic haemodynamic changes 1. Some key features of INCPH include:
- Phlebosclerosis, which is generally regarded as the primary lesion in the development of the intrahepatic haemodynamic changes 1
- Nodular regeneration, which is a result of the disturbed intrahepatic circulation and subsequent parenchymal remodeling 1
- Sinusoidal dilatation, which is often present, particularly in periportal areas 1
- Para-portal shunt vessels, which are a result of the increased portal pressure 1
- Perisinusoidal fibrosis, which is a characteristic feature of INCPH 1 It is essential to note that liver histology remains crucial in the diagnosis of INCPH, and a sufficient specimen size is needed to demonstrate the presence of these lesions 1. A liver biopsy is recommended for the diagnosis of INCPH, as it allows for the exclusion of cirrhosis and other causes of non-cirrhotic portal hypertension 1.
From the Research
Histological Findings of Idiopathic Noncirrhotic Portal Hypertension
The histological findings of idiopathic noncirrhotic portal hypertension (INCPH) are heterogeneous and often subtle, making diagnosis challenging even for experienced hepatopathologists 2. Some common histological features of INCPH include:
- Portal vein sclerosis, which is considered a strong independent histologic predictor for INCPH 2
- Obliterative portal venopathy (OPV), which is characterized by the presence of shunt vessels, phlebosclerosis, and increased number of portal vessels 3
- Incomplete septa and nodular regenerative hyperplasia, which can be seen in some cases of INCPH 4, 3
- Aberrant portal/periportal vessels, which were previously thought to be a characteristic feature of INCPH, but have been found to not significantly contribute to the positive assignment of OPV status 2
Prevalence of Histological Features
Studies have shown that histological features of INCPH can be seen in incidental liver biopsies and fatty liver disease without portal hypertension 3. In one study, at least one feature of INCPH was noted in 90% of the biopsies, and 10% of the biopsies showed 5-6 features of INCPH without portal hypertension 3.
Diagnostic Criteria
A three-tiered classification with diagnostic criteria has been proposed to facilitate the histologic assignment of OPV status for the evaluation of INCPH 2. This classification takes into account the presence of portal vein sclerosis and other histological features, and can aid in practical histologic assessment of liver biopsies with or without portal hypertension. The diagnosis of INCPH is based on clinical criteria and the formal exclusion of any other causes of portal hypertension, and a formal diagnosis is based on the presence of unequivocal signs of portal hypertension, absence of cirrhosis, advanced fibrosis or other causes of chronic liver diseases, and absence of thrombosis of the hepatic veins or of the portal vein at imaging 5.