Focus on dysplastic nodules and early hepatocellular carcinoma: an Eastern point of view.

Although increasing numbers of equivocal nodular lesions have been detected in patients with liver cirrhosis with the development of various diagnostic imaging modalities, the pathological diagnosis of small, well-differentiated hepatocellular carcinoma (HCC) in the early stage and of high-grade dysplastic nodules (DNs) is a controversial issue among both Japanese and Western pathologists. In particular, many of the vaguely nodular HCCs of well-differentiated HCC diagnosed by Japanese pathologists tend to be interpreted as high-grade DNs rather than HCC by Western pathologists. In contrast, many of the high-grade DNs diagnosed by Western pathologists are interpreted as well-differentiated HCC by Japanese pathologists. The reasons for the discrepancy between Japanese and Western pathologists can be explained by the following: for Western pathologists, most information comes from the study of HCC and advanced cirrhosis explanted at liver transplantation without detailed clinical information about the nodules; for Japanese pathologists, most information comes from the examination of surgical and biopsy materials together with detailed clinical information that includes meticulous follow-up data on the clinical course of the nodular lesions. To resolve the diagnostic confusion concerning equivocal nodular lesions in the cirrhotic liver, it is necessary to promote the active exchange of clinicopathologic information between Japan and Western countries.