Micronodular Transpormation (Nodular Regenerative Hyperplasia) of the Liver: A Report of 64 Cases Among 2,500 Autopsies and A New Classification of Benign Hepatocellular Nodules

Abstract

Nodular regenerative hyperplasia is defined by he–patocellular nodules distributed throughout the liver in the absence of fibrous septa between the nodules. Most reports have been single cases so that the prevalencend clinical significance of nodular regenerative hyperplasia is uncertain. In this study, the hepatic histology of 2,500 consecutive autopsies was reviewed. A spectrum of nodular regenerative hyperplasia present in 2.6% of autopsy livers and qualitatively similar but lesser degrees of noduler transformation was found with nodular regenerative hyperplasia present in 2.6% of autopsy livers and qualitatively similar but lesser degrees of nodular transformation in a further 10.2%. Nodular transformation was also seen in 47% of livers with cirrhosis and 69% with portal veins was seen in all cases with nodlular regenerative byperplasal, but only 4.7% of these had evidence of portal hypertension. The prevalence of various clinical states was compared in nodular regenerative hyperplasia and in controls. The reslults confirm, extend and quantify the spectrum of associated diseases. Nodular regenerative hyperplasia occurs in 5. 6% of individuals over age 80 and with increased frequency in patients with arteritis, polymyalgia rheumatica, massive tumor infiltration and mineral oil deposition. Nodular tumor infiltrtion and mineral oil deposition. Noduler regenerative hyperplasia appears to be the hepatic analogue of arterial and arteriolar nephrosclerosis. A new classification of nodular transformation is proposed that encompasses the specturm of lessions described here and the previously defined entities of focal nodular hyperplasia, parial nodular transformation and “cirrhosis telangiectasia hepatis.” The major conclusion is that nodular regenerative yperplasia is a secendary and nonspecific tissue adaptation to tation to heterogeneous distribution of blood flow and does not represent a specific entity.(HEPATOLOGY 1990; 11:787–797.)