Abstract. Twenty-four adenocarcinomas of the hepatobiliary system were found among I10 primary hepatic neoplasms; 22 of these were intrahepatic, one involved the extrahepatic bile duct and one the gall bladder. Histologically, 10 intrahepatic neoplasms were classified as cholangiocarcinoma, and 12 as bile duct cystadenocarcinoma. The former were characterized by tubular structures lined by anaplastic cuboidal or columnar cells with diffuse fibrous stroma, and the latter by multiple cystic structures with papillary and solid areas. Half the bile duct cystadenocarcinomas showed benign cysts and transition to adenocarcinoma. This was seen in only one case of cholangiocarcinoma. The extrahepatic bile duct carcinoma was characterized by tubular structures lined with flattened cuboidal cells with scant stroma. The gall bladder adenocarcinoma contained many acinar structures lined with columnar or cuboidal cells and separated by thin stroma. Distant metastasis was found in 87.5% (21 of 24) of the bile duct adenocarcinomas; the lymph nodes, lungs and peritoneum were the common sites of metastasis.The biliary system can be divided anatomically into three segments: the intrahepatic and extrahepatic bile ducts, and the gall bladder. Carcinomas of all three segments have been described in man [I, 7, 8, 13 We analyze 24 biliary system neoplasms, and describe their clinical, gross morphologic and histologic characteristics.
Materials and MethodsThe 110 primary hepatic neoplasms found in 12,245 necropsies of dogs done at The Animal Medical Center were studied as described in a previous report [ 151. Of these neoplasms, 24 originated from the biliary system: 22 from the intrahepatic bile ducts, one from an extrahepatic bile duct and one from the gall bladder.Formalin-futed tissues were processed routinely, and sections 4 to 6 pm thick were stained with hematoxylin and eosin (HE), mucicarmine, and periodic acid-Schiff (PAS).
ResultsThe frequency of bile duct carcinoma in this study was 22% of the primary hepatic neoplasms and 0.2% of the necropsy population. The majority of bile duct carcinomas occurred in dogs over 10 years of age (63%; 15 of 24) and in females (58%; 14 of 24). The neoplasms were found in eight different breeds, and no breed predisposition was found. Anorexia, lethargy, ascites and dyspnea were the common clinical signs. Thirteen percent (2 of 15) were icteric; one of these was the dog with extrahepatic bile duct carcinoma. One dog had myelopathy caused by metastasis, one had seizures, and one had vomiting. Leukocytosis and increased serum alkaline phosphatase were recorded in three of four dogs.Gross morphologic descriptions adequate to classify the intrahepatic bile duct carcinomas into massive, nodular or diffuse lesions were available for 18 dogs. In nine, the neoplasm consisted of a large mass in one of the liver lobes: five in the left lateral lobe, two in the central lobe, one each in the right lateral and right medial lobes. In six of these, smaller metastatic lesions were found in other lobes. Nodular...