One hundred seventy-six canine lymphomas were classified morphologically using four of the major human lymphoma classification schemes (Rappaport, Lukes-Collins, Kiel, and the Working Formulation). All 176 dogs received the same chemotherapeutic protocol. Sixty-two of these lymphomas had their immunophenotypes established by examination of cell surface markers by automated cytofluorography. Several different morphologic types of canine lymphoma were identified and these were comparable to morphologic categories in human classification schemes. Follicular and low grade lymphomas were rare. The two most common morphologic types were diffuse large cell (centroblastic) and immunoblastic. The Kiel classification appeared to be the most useful human scheme for classifying the canine lymphomas. Cytofluorographic analysis was generally straightforward, and 60 of the 62 lymphomas were placed into one of three immunophenotypic categories: 27 pan-T(LQ1)+SIg+, 21 pan-T(LQ1)-SIg+, and 12 pan-T(LQ1)+SIg-. Two of the lymphomas could not be characterized immunologically because a pre-existing or reactive non-neoplastic population of lymphocytes made interpretation of single cell suspension analysis difficult. The authors identified correlations between morphology and survival and disease-free remission; dogs with high-grade tumors generally survived the longest and had the longest remissions. No correlations were identified between high concentrations of serum lactate dehydrogenase, age, sex, or stage of disease, and morphology, immunophenotype, remission, or survival times. A significant correlation between clinical illness and survival time was documented. The median age of the dogs was nine years, no significant effect of sex on prevalence was observed, and some breeds were significantly overrepresented. Significant morphologic-immunophenotypic correlations included shorter remission and survival times for T-cell tumors than B-cell tumors, and a highly significant correlation between the pan-T(LQ1)+SIg-"T cell" phenotype and hypercalcemia.

We studied 232 dogs that underwent mastectomy for mammary epithelial neoplasms. The mastectomy specimens were evaluated according to structural parameters found to be prognostically significant in human mammary neoplasms, such as grade of atypia in non-invasive proliferations of duct epithelium, extent of malignant disease, and nuclear differentiation in malignant neoplasms. In this study, the biologic behavior of mammary lesions was assessed according to the frequency of development of de novo or recurrent invasive carcinoma within two years. Our data indicate that we can recognize structural variables which permit classification of mammary neoplasms into categories with distinct patterns of biologic behavior. In addition to normotypic proliferative lesions and invasive malignant neoplasms, we were able to identify precancerous atypic and non-invasive malignant neoplasms that are considered precursor lesions in women. Also, as in women, nuclear differentiation was found to be a prognostically significant variable. Lymphoid cellular reactions, considered to be structural correlates of host-tumor immune responses in women, were noted in 35% of dogs with precancerous or malignant neoplasms. Application of the described parameters should facilitate comparative studies of canine and human mammary carcinogenesis and use of the dog as a model for the development of new therapeutic modalities and immunoprophylaxis of human mammary cancer.

Abstract. 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 carcinoma 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.Neoplasms of the liver and biliary tracts are uncommon in domestic animals [3,6,15,16,22,23,26,31, 361. Frequency in the dog vanes from 0.6% to 1.3% of all neoplasms [6,9,15,16,18,31,33]. Only a few studies deal with the clinicopathologic features of a large number of canine primary hepatic neoplasms [4, 12,14,15,28,31,331. Materials and MethodsCase records and histologic specimens from dogs with hepatic neoplasms seen between 1962 and 1977 at The Animal Medical Center were reviewed. AU cases with enough slides to confirm the diagnosis were included in the study. Details of the 110 dogs' clinical and gross pathologic fmdings were collected from the medical and necropsy records. Because neoplasms arising from the hematopoietic and vascular systems usually involve several organs, they were excluded from this study. Hepatocellular adenoma, intrahepatic bile duct adenoma and bile duct cyst adenoma also were excluded because of their high frequency and because of the difficulty in distinguishing between nodular hyperplasia and hepatocellular adenoma.The hepatic neoplasms were grouped under hepatocellular carcinoma, bile duct carcinoma, 553