Clinicopathological significance of adenomatous hyperplasia of the liver

: Adenomatous hyperplasia (AH) is defined as a discrete nodular lesion showing varying degrees of hepatocyte hyperplasia in chronic liver disease, particularly in liver cirrhosis. Recently, AH has attracted the attention of both clinician and pathologist regarding the possibility of the precursor lesion of hepatocellular carcinoma (HCC) because AH is frequently coexistent with HCC and occasionally contains foci of well-differentiated HCC within a nodule. Of the 60 resected HCCs, smaller than 2 cm in diameter, in case of liver cirrhosis in our hospital, AH was found in the vicinity of HCC of 7 cases (12%). Of the 8 autopsy cases of HCCs, smaller than 2 cm in diameter with liver cirrhosis, AH was found in the vicinity of HCC of 3 cases (37.5%). On the other hand, there was no association of AH in 94 resected HCCs with chronic hepatitis. Furthermore, among 51 autopsy cases of liver cirrhosis, 41 nodular lesions, smaller than 2 cm in diameter, were found and 23 large regenerative nodules (56.1%), 6 AHs (14.6%), 4 AHs containing cancerous foci (9.8%) and 8 HCCs (19.5%). Accordingly, if AH could be a precursor of HCC, it could be said that approximately 12-37.5% of HCC would be multicentric origin and the association of liver cirrhosis would be inevitable for the multicentric occurrence of HCC from the view point of morphologic observation. Together with frequent association of HCC and AH, and the presence of AH containing HCC foci, AH may have a high potency of a precursor lesion, and it is important to conduct a meticulous follow-up for AH.