Noncirrhotic portal hypertension.

Portal hypertension is characterized by an increase in portal pressure (>10 mm Hg) and could be a result of cirrhosis of the liver or noncirrhotic diseases. Noncirrhotic portal hypertension (NCPH), as it generally is termed, is a heterogeneous group of diseases that is due to intrahepatic or extrahepatic etiologies. In general, the lesions in NCPH are vascular in nature and can be classified based on the site of resistance to blood flow. Noncirrhotic portal fibrosis and extrahepatic portal vein obstruction are two diseases that are common in developing countries; they most often present only with features of portal hypertension and not of parenchymal dysfunction. These are described in detail.