Histology of portal vascular changes associated with idiopathic non‐cirrhotic portal hypertension: nomenclature and definition

Abstract

Idiopathic non-cirrhotic portal hypertension (INCPH) is a rare vascular liver disease that has attracted new interest in recent years. It is characterised by clinical signs of portal hypertension in the absence of cirrhosis or severe fibrosis and any known cause of portal hypertension. As much uncertainty exists about INCPH pathophysiology, and no definite diagnostic tests are available, liver biopsy is an essential tool for achieving a definite diagnosis. Unfortunately, the histological diagnosis of INCPH is not always straightforward, as the characteristic lesions are unevenly distributed, vary greatly in their severity, are often very subtle, and are not all necessarily present in a single case. Furthermore, specifically for the characteristic portal vessel changes observed in INCPH, the terminology and definition are ambiguous, which adds complexity to the already complex clinicopathological scenario. An international study group of liver pathologists and hepatologists pursued a consensus on nomenclature for the portal vascular lesions of INCPH. Such standardisation may assist pathologists in the recognition of such lesions, and will possibly facilitate further advancement in this field.

Aberrant von Willebrand factor expression of sinusoidal endothelial cells and quiescence of hepatic stellate cells in nodular regenerative hyperplasia and obliterative portal venopathy

“…The diagnosis of NRH was made when the liver parenchyma showed nodular configuration with central hyperplastic hepatocytes surrounded by peripheral atrophic hepatocytes but no fibrosis 10,25 . The diagnosis of OPV, previously known as hepatoportal sclerosis, was made when the portal tract demonstrated portal fibrosis with phlebosclerosis and/or other portal vascular changes, such as herniated portal veins, hypervascularised portal tracts and periportal abnormal vessels 8–10,25 . Evidence of clinical portal hypertension included any of the following features: oesophageal varices, hypersplenism, ascites or increased hepatic venous pressure gradient.…”

“…OPV is an under‐recognised disease of unclear aetiology and the diagnosis can be easily overlooked on needle liver biopsy 7,8 . OPV is characterised by portal fibrosis and obliteration of small and medium branches of the portal vein, 9,10 resulting in the development of portal hypertension and its sequelae. Patients with OPV often present with variceal bleeding, splenomegaly and thrombocytopenia and only mildly abnormal liver tests.…”

Vascular Liver Disorders, Portal Vein Thrombosis, and Procedural Bleeding in Patients With Liver Disease: 2020 Practice Guidance by the American Association for the Study of Liver Diseases

“…In addition to the absence of cirrhosis, various vascular histopathological lesions have been described in patients with INCPH, including intrahepatic PV stenosis (also called obliterative portal venopathy), nodular regenerative hyperplasia, or incomplete septal cirrhosis, as well as less specific but suggestive histological alterations, such as herniated PVs, hypervascularized portal tracts, abnormal periportal vessels, sinusoidal dilatation, or regenerative hepatocytes. ( 266 ) An overarching entity called portosinusoidal vascular disease (PSVD) has been proposed to account not only for INCPH, but also for the increasingly reported similar histopathological anomalies in patients without portal hypertension. ( 267‐269 )…”

Causes and Management of Non-cirrhotic Portal Hypertension​

“…Biopsy remains mandatory to confirm the diagnosis of PSVD. Since the typical histological lesions cannot be all always contemporary present and they are distributed in a focal way, it is necessary to have an adequate liver specimen (Table 2 ) [ 4 ••, 11 •]. The optimal sample should measure more than 20 mm of length and contain at least 10 portal spaces, and it should be low fragmented.…”