Diagnostic discrepancy of early hepatocellular carcinoma between Japan and West.

The diagnoses for a range of hepatocellular neoplastic lesions amongst Japanese and Western pathologists show a striking lack of consistency, especially in distinguishing dysplastic nodules (DN) from very well-differentiated hepatocellular carcinomas (HCC). Namely, very well-differentiated HCC showing a vaguely nodular appearance diagnosed by Japanese pathologists tends to be diagnosed as high-grade DN by Western pathologists. Both Japanese and Western pathologists agreed that "stromal invasion", which is tumor cell invasion into the intra-tumoral portal tracts, is considered the most helpful morphologic clue to distinguish high-grade DN from well-differentiated HCC.