Bile duct adenoma and von Meyenburg complex-like duct arising in hepatitis and cirrhosis: pathogenesis and histological characteristics.

Morphologic features and neoplastic potentials of bile duct adenoma (BDA) and von Meyenburg complex (VMC)-like duct arising in chronic liver disease were unknown. Thirty-five BDAs and 12 VMC-like duct lesions were observed in 39 cases with chronic liver disease. BDAs were divided into the EMA-cytoplasmic type (n = 14) and EMA-luminal type (n = 21). EMA-cytoplasmic BDA composed of a proliferation of cuboidal to low-columnar cells forming an open lumen with NCAM(+)/MUC6(-), resembling an interlobular bile duct. EMA-luminal BDA showed uniform cuboidal cells with narrow lumen, and NCAM(++)/MUC6(++), resembling a ductular reaction. VMC-like duct showed positive MUC1 expression and negative MUC6. The expression of S100P, glucose transporter-1 (GLUT-1) and insulin-like growth factor II mRNA-binding protein 3 (IMP-3) were not detected in three lesions. p16 expression was higher than those of the ductular reaction, and the Ki67 and p53 indexes were very low (<1.0%). Large-sized EMA-luminal BDA shows sclerotic stroma. We classified small nodular lesions of ductal or ductular cells in chronic hepatitis and cirrhosis into the following groups: BDA, interlobular bile duct type; BDA, ductular/peribiliary gland type; and VMC-like duct. They may be reactive proliferation rather than neoplastic lesions.