Histogenesis of Malignant Liver Tumors Induced by Dimethylnitrosamine. An Experimental Study in Syrian Hamsters

Summary

The histogenesis of malignant liver tumors induced by dimethylnitrosamine was studied in Syrian hamsters. The observed series of lesions that starfed from simple proliferation of reticuloendothelial cells developed into tumors that had the characteristic histological picture of hemangioendothelial sarcomas with multiple lung metastases. The sequential series of lesions that started out as simple bile-duct hyperplasia eventuated in cholangiofibrosis. Cholangiofibrosis appears to be the usual precursor for the development of cholangiocarcinomas. No tumors of hepatic cell origin were observed. The concept that all induced malignant tumors of the liver in laboratory animals arise from hepatic cells is not valid for Syrian hamsters.