Unusual hepatocellular lesions in primary biliary cirrhosis resembling but unrelated to hepatocellular neoplasms

Summary Structural, cellular and nuclear abnormalities of hepatocytes are a histological hallmark of well-differentiated, small hepatocellular carcinoma (HCC) or its borderline lesion. This study revealed that several hepatocellular abnormalities found in these hepatocellular neoplasms were also found in non-cirrhotic stages of primary biliary cirrhosis (PBC) in which HCC is unlikely to develop. These changes are small cell changes, consisting of the appearance of small hepatocytes arranged in thin trabecular or compact patterns with increased cellularity and basophilic cytoplasm. This was found in 36%, 71% and 100% in specimens of stages 1, 2 and 3, respectively. Large cell changes occurred and consisted of large hepatocytes with large nuclei and prominent nucleoli, found in 27%, 47% and 22% of the stages, respectively. Finally, liver cell rosettes were seen, showing variable acinar formation and present in 0%, 41% and 33% of the stages, respectively. These lesions were identified microscopically as irregularly shaped areas or vague nodules of hepatocytes without a fibrous rim, in the hepatic lobules. They showed an expansive growth or shaggy border against the surrounding hepatic parenchyma. Follow-up studies, including autopsies, failed to show development of HCC or its borderline lesion in PBC cases. Pathologists must make a diagnosis of HCC and its borderline lesion bearing in mind the occurrence of such unusual hepatocellular lesions probably of a reactive nature.