Ultrastructural study of the initial phases of pancreatic carcinoma induced by BOP in the Syrian golden hamster

: A serial study was carried out on the lesions induced by N-nitroso-bis(2-oxopropyl)amine (BOP) in the Syrian golden hamster until the appearance of pancreatic ductal carcinomas. During the initial phase, first findings were cytolysis of acinar cells close to blood vessels and other cells, together with a loss of zymogen granules from the cytoplasm, and an increase in the diameters of the acinar lumens. After week 11 a proliferation of ductule-like cells was observed. We consider that a minimum proliferation of cells at the acinus-ductule junction would give rise to pseudoductules composed of remains of acinar cells together with ductule-like cells.