Idiopathic noncirrhotic portal hypertension: current perspectives

Abstract

The term idiopathic noncirrhotic portal hypertension (INCPH) has been recently proposed to replace terms, such as hepatoportal sclerosis, idiopathic portal hypertension, incomplete septal cirrhosis, and nodular regenerative hyperplasia, used to describe patients with a hepatic presinusoidal cause of portal hypertension of unknown etiology, characterized by features of portal hypertension (esophageal varices, nonmalignant ascites, porto-venous collaterals), splenomegaly, patent portal, and hepatic veins and no clinical and histological signs of cirrhosis. Physicians should learn to look for this condition in a number of clinical settings, including cryptogenic cirrhosis, a disease known to be associated with INCPH, drug administration, and even chronic alterations in liver function tests. Once INCPH is clinically suspected, liver histology becomes mandatory for the correct diagnosis. However, pathologists should be familiar with the histological features of INCPH, especially in cases in which histology is not only requested to exclude liver cirrhosis.

Keywords: esophageal varices; idiopathic portal hypertension; obliterative portal venopathy; splenomegaly.

Figure 1

Histologic features of the portal tracts in INCPH. Notes: (A) Obliterative venopathy: portal vein with a reduced lumen (arrow) within a fibrotic portal tract; hematoxylin and eosin stain, original magnification ×10. (B) Obliterative venopathy: a fibrotic portal tract (white arrow) with a rounded contour and a small portal branch showing a thickened wall (arterialization): hematoxylin and eosin stain, original magnification ×20 (C) Obliterative venopathy: immunostain with antismooth muscle actin antibodies highlights smooth muscle cells hyperplasia in portal vein branch arterialization (asterisk); original magnification ×20. (D) Paraportal shunt: dilated, thin-walled portal vascular channel herniating into the surrounding parenchyma (asterisk); picrosirius red stain, original magnification ×10. (E) Marked portal vein dilation: the enlarged portal branch (asterisk) is at least three times greater than the size of the bile duct; picrosirius red stain, original magnification ×20. (F) Increased number of portal vascular channels (arrows); hematoxylin and eosin stain, original magnification ×10. Abbreviation: INCPH, idiopathic noncirrhotic portal hypertension.

Figure 2

Histologic features of the liver parenchyma in INCPH. Notes: (A) Sinusoidal dilatation with perisinusoidal fibrosis: dilated sinusoids are wider than one liver cell plate and are rimmed by a thin layer of collagen; picrosirius red stain, original magnification ×10. (B) Nodular regeneration: hyperplastic hepatocytes (asterisk) are surrounded by atrophic hepatocytes (arrow), in absence of fibrous septa; reticulin stain, original magnification ×10. (C) Organizing thrombus within a medium-sized portal branch; hematoxylin and eosin stain, original magnification ×5; (D) Platelet deposits within sinusoids (arrow); hematoxylin and eosin stain, original magnification ×100. Abbreviation: INCPH, idiopathic noncirrhotic portal hypertension.