Nodular transformation of the liver associated with portal and pulmonary arterial hypertension.

A case of multiple focal nodular hyperplasia (FNH) of the liver associated with noncirrhotic portal hypertension and later complicated by pulmonary arterial hypertension leading to death from right heart failure is reported. In retrospect, the portal hypertension diagnosed in early life was most likely due to a congenital hypoplasia of portal vein branches and multiple FNH, a hyperplastic response of the liver parenchyma in association with anomalies of hepatic arterial branches as found within the lesions. This case may represent a form of multiple FNH syndrome restricted to the liver, because neither extrahepatic vascular malformation nor brain tumor was identified at autopsy. The FNH lesions had considerably expanded over the years, and the severe sinusoidal congestion due to chronic right-sided heart failure with subsequent prolonged parenchymal exposure to blood-borne hepatotrophic factors is a likely explanation for both the massive enlargement of FNH lesions and the nodular regenerative hyperplasia observed in the intervening parenchyma.