Partial nodular transformation of the liver with portal vein thrombosis. A report of two autopsy cases.

Partial nodular transformation (PNT) of the liver is a rare condition in which nonfibrous nodules composed of hyperplastic hepatocytes replace the hepatic parenchyma around the hepatic hilus. We report two autopsy cases involving PNT of the liver with portal vein thrombosis. Case 1 was a 27-year-old man with malignant lymphoma. Ascites gradually increased, and he died 4 years after the onset of his illness. Case 2 was a 73-year-old woman treated for cirrhosis for 4 years who died of renal failure. Postmortem examination of these two cases revealed numerous coalescent nodules in the hilus of the liver as well as portal vein thrombus in the hilus. Microscopically, these nodules in the perihilar area were composed of hyperplastic hepatocytes without fibrous rim, and the peripheral parenchyma showed atrophy to some extent. The portal vein thrombi in the hilus and large portal tracts were mainly fresh and partially organized. Portal vein branches in the peripheral small portal tracts were devoid of significant pathologic changes. We suggest that PNT of the liver in our cases occurred as the result of uneven blood supply to the perihilar parenchyma due to portal vein thrombosis in the hepatic hilus.