Canine hepatocellular carcinoma.

In a study of 110 primary hepatic neoplasms in dogs, 55 hepatocellular carcinomas and two combined hepatocellular and cholangiocarcinomas were diagnosed. These neoplasms were classified into the following 11 groups based on histo-architectural pattern: trabecular, peliod, cobblestone, peritheliomatous, anaplastic, pseudoglandular, pleomorphic, scirrhous, clear cell, solid, and combined hepatocellular and cholangiocarcinoma. The neoplastic hepatocytes varied from almost normal to highly anaplastic spindle cells. Pleomorphic and giant cells were common in some groups, rare or absent in others. Metastasis was found in 61% (35 of 57 dogs), with varied frequencies in the different groups. Cirrhosis was found in only 7% (4 of 57), in contrast to a much higher percent in man, indicating the possibility of a different pathogenesis in the dog.