Histogenesis of cholangiomas and cholangiocarcinomas in thioacetamide fed rats.

A sequential, histologic analysis of the livers of male albino rats chronically fed the hepatocarcinogen thioacetamide (TAA) is performed after one, two, three, four, eight and twelve months of treatment. Liver cell alterations present after one, two and three months consist of centrolobular liver cell degeneration and oval cell proliferation. After 8 months of TAA treatment, a variety of benign tumors (cystadenomas, angiomas, cholangiomas) is observed. From the 12th month all experimental animals develop cholangiocarcinomas. Pulmonary metastases are discovered after 15 months. The role of the oval cells in relation to the later appearing cholangiocarcinoma is discussed. A review of literature is given.