hyperplasia, desquamation and proliferation of the bile-duct lining cells, glandular formation and fibrosis of the periductal connective tissue of the walls are the commonest

3/15 had cholangiocarcinomas, 3/15 had cholangiofibromas and 6/15 had cholangiofibroses. ln the group with combined treatment but given praziquantel three days before NDMA, 11/15 animais developed cholangiofibroses. ln the group given NDMA alone, 4/15 animaIs had cholangiofibroma and 5/15 had cholangiofibroses; and in the group receiving only helminthic infection, 12/15 animais developed cholangiofibroses. No cancerous or precancerous lesion ofthe bile duct was found in the untreated control group (Lee et al., 1994).