In order to reveal the precursor lesion of hepatocellular carcinoma, a histopathologic study was performed on 141 cases of liver cirrhosis with or without hepatocellular carcinoma. Exclusive of primary or metastatic hepatocellular carcinoma nodules, 94 nodular lesions (>5 mm) were detected in 53 cirrhotic livers. They consisted of 83 large regenerative nodules and 11 dysplastic nodules. Besides some common features with those observed in the former type, the dysplastic nodules presented increased cytoplasmic basophilia, nuclear and nucleolar enlargement, nuclear crowding, occasional microacinar formation and proliferation of the hepatocytes within fibrous septa. These changes were not substantial enough to allow the diagnosis of hepatocellular carcinoma. In one case, however, malignant transformation of hepatocytes was suspected because of their pattern of extranodular outgrowth. It is important to recognize these subtle abnormalities in order to define premalignant hepatic lesions. A possible connection between benign large regenerative nodules and dysplastic nodules is also discussed.
Although many investigators have suggested that there are precancerous lesions of hepatocellular carcinoma (HCC), no unifying concept exists with respect to their morphologic characteristics. Recent advances in diagnostic procedures have facilitated detection of minute nodular lesions arising in the liver which need to be defined histologically prior to determining the appropriate treatment. In Japan, HCC usually develops in close association with preexisting liver cirrhosis. Cirrhotic livers are therefore believed to have a precancerous lesion, which will become recognizable as a small nodule. These considerations have led us to reexamine various nodular lesions occurring in cirrhotic livers.
This paper describes the histologic findings of these lesions. They are indeed different from a definite HCC but seem to be closely related to the development of HCC.
Methods
A total of 141 autopsy cases of liver cirrhosis with or without HCC were studied during the period from 1978 to 1985. One hundred twenty cases were thought to be posthepatitic (mixed