THE SO-CALLED BILE-DUCT ADENOMA IS A PERIBILIARY GLAND HAMARTOMA

The cell phenotype of so-called bile duct adenoma (BDA) was investigat ed immunohistochemically using monoclonal antibodies to two recently i dentified antigens (designated D10 and 1F6) extracted from human liver and cultured biliary epithelium. The acini and tubules of BDA consist ed of serous and mucous cells that expressed D10 and 1F6. The intrahep atic peribiliary glands of normal liver, comprising intramural mucous glands and extramural tubuloalveolar seromucinous glands, similarly ex pressed D10 and 1F6 antigens. Antigen 1F6 was present in the cells for ming the canals of Hering and normal bile ductules but not in interlob ular and larger bile ducts. Proliferating bile ductules associated wit h large bile duct obstruction and alcoholic cirrhosis or the epithelia of the von Meyenberg complex and polycystic liver did not exhibit thi s combined profile of D10 and 1F6 expression and mucous cells, These f indings suggest an origin of BDA from peribiliary glands rather than f rom bile ductules or ducts. Consistent with this view was our finding that 18 of the 30 BDA were spatially related to a large-calibre bile d uct, Therefore, BDA, well known for its benign behavior, is a small ma ss of disorganized but mature peribiliary gland acini and tubules with in a variable amount of stroma and should properly be called a peribil iary gland hamartoma.