Canine hepatic neoplasms: a clinicopathologic study.

One hundred ten primary hepatic neoplasms, excluding hematopoietic and vascular tumors, were diagnosed in 12,245 canine necropsies. Included were 55 hepatocellular carcinomas, 24 bile duct carcinomas, 2 combined hepatocellular and cholangiocarcinomas, 15 carcinoids and 14 sarcomas. A majority of the dogs with hepatocellular carcinoma (80%), bile duct carcinoma (65%) and sarcoma (61%) were 10 years old or older; 71% of the dogs with carcinoid were under 10 years old. Hepatocellular carcinoma and sarcoma occurred more often in males, bile duct carcinoma in females, and no sex predisposition was found in dogs with carcinoid. All dogs had hematologic and biochemical abnormalities relating to liver function. The aspartate amino transferase/alanine amino transferase ratio was less than one in cases of hepatocellular carcinoma and bile duct carcinoma, and more than one in cases of carcinoid and sarcoma. A massive lesion in one of the liver lobes was the most common gross morphologic feature in cases of hepatocellular carcinomoa and bile duct carcinoma, with the left lateral lobe affected most often. In cases of carcinoid, most of the lesions were diffuse. The most common sites of metastases were lymph nodes and lungs for hepatocellular carcinoma and bile duct carcinoma, lymph nodes and peritoneum for carcinoid, and spleen for sarcoma.