Radiological and histopathological manifestations of hepatocellular nodular lesions concomitant with various congenital and acquired hepatic hemodynamic abnormalities

Congenital and acquired hepatic hemodynamic abnormalities are classified into four categories: hepatic arterial inflow disorder, portal vein inflow disorder, hepatic vein outflow disorder, and presence of a third inflow to the liver. Although their detailed etiology is not fully understood, these hepatic hemodynamic abnormalities may cause the formation of hepatocellular nodules. Recent advances in imaging modalities now enable visualization of these hepatocellular nodules concomitantly with the identification of various congenital and acquired hemodynamic abnormalities. Most of these nodular lesions are benign hyperplastic nodules, such as focal nodular hyperplasia, nodular regenerative hyperplasia, and other types of regenerative nodules. However, neoplastic nodules such as hepatic adenoma and hepatocellular carcinoma may also occur in conjunction with hepatic hemodynamic abnormalities. Distinguishing neoplastic nodules, especially malignant liver tumors, from hyperplastic nodules is important. Detection of intranodular Kupffer cells with superparamagnetic iron oxide enhanced magnetic resonance imaging is a key indicator that a nodule is regenerative rather than neoplastic.