Fig. 5

Representative micrographs of cholangiocarcinoma (CCA) and its precursor lesions in H&E-stained sections. A primary lesion from the bile duct is indicated by CK19 staining, in hamster livers infected with Opisthorchis viverrini and receiving NDMA, at 5 months. A–C Malignant transformation of cholangiofibrosis; D–F malignant transformation of cholangiofibroma; CCA (black arrows). Note abnormal overlapping and piling up of cells and gland formation at a metaplastic duct (yellow arrows), with proliferation of atypical ductules in the hepatic parenchyma (black arrows). G–I CCA, a well-differentiated adenocarcinoma producing mucin; malignant transformation from a dilated metaplastic duct (yellow arrows), is noted. J–L CCA (black arrows), a moderately differentiated adenocarcinoma with mild production of mucin, malignant transformation foci are obscured