Idiopathic noncirrhotic portal hypertension.

Cirrhosis is the most common cause of portal hypertension but there are many causes of noncirrhotic portal hypertension. Many of these etiologies may be diagnosed by liver biopsy. Idiopathic noncirrhotic portal hypertension is being increasingly diagnosed and has varied histopathological findings as well as overlapping definitions. Many of these histological changes can be subtle, thus making it a challenging diagnosis for the pathologist to make. This review summarizes the clinical aspects of idiopathic noncirrhotic portal hypertension and outlines the different definitions and histological features of the entity. In addition, pearls and pitfalls for the pathologist in making this diagnosis are included.