Pathologic Observations of Intrahepatic Peribiliary Glands in 1000 Consecutive Autopsy Livers: Heterotopic Pancreas in the Liver

One thousand consecutively autopsied livers were examined for intrahepatic heterotopic pancreas. Heterotopic pancreas in the liver was found in 41(4.1%) of the 1000 livers. It occurred with nearly equal frequency in "normal" livers and variously diseased livers. Histologically, heterotopic pancreas was situated exclusively in the large- and medium-sized portal tracts, and its size ranged from 250-900 μm in diameter. It was intermingled with intrahepatic peribiliary glands and appeared to communicate with bile duct lumina. Heterotopic pancreas consisted of three cell types: acinar cells with eosinophilic zymogenlike granules, clear cells resembling centriacinar cells, and ductular elements. Langerhans' islets were not found in any cases. Immunohistochemically, constituent cells of heterotopic pancreas contained pancreatic α-amylase and trypsin but lacked argentaffin and argyrophilic cells as well as insulin-, glucagon-, and somatostatin-immunoreactive endocrine cells. Ultrastructurally, acinar cells contained many dense granules regarded as zymogen granules. It is indicated that intrahepatic heterotopic pancreas occurs in large portal tracts. It may modify hepatic bile by secreting pancreatic enzymes into intrahepatic bile duct lumina.