Owing to the development of Greyhounds as racing sighthounds, these dogs have acquired unique physiologic adaptations that distinguish them from other breeds. Reference intervals for many analytes in retired racing Greyhounds (RRGs) differ from those of other breeds; most of the hematologic differences have also been described in other sighthounds. In this review, we provide a survey of the literature on clinical pathology of Greyhounds and other sighthounds and results of laboratory testing, including analysis of CBCs, biochemical profiles, coagulation tests, and blood gases, in RRGs at The Ohio State University. Major clinicopathologic differences in this breed include higher RBC mass, creatinine concentration, glomerular filtration rate, activities of hepatic enzymes, and concentration of cardiac troponin, as well as lower WBC, neutrophil, and platelet counts, thromboelastographic values, and concentrations of serum haptoglobin, total globulins, and T4.

Background: Histiocytic sarcoma is an aggressive neoplasm of dendritic cells that carries a grave prognosis. The efficacy of chemotherapy against this disease is unknown. The purpose of this study was to determine the efficacy of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) in dogs with incompletely resected or metastatic histiocytic sarcoma, to describe the clinical characteristics of these dogs, and to identify factors affecting prognosis.Hypothesis: Our hypothesis is that CCNU has activity against canine histiocytic sarcoma and can improve survival in dogs with advanced disease.Animals: Included in analysis are dogs diagnosed with histiocytic sarcoma who had gross measurable or residual microscopic disease and who received CCNU.Methods: A multi-institutional, retrospective, single-arm cohort study was conducted. Available biopsy samples were tested with an antibody against CD18 when possible to confirm the diagnosis of histiocytic sarcoma.Results: Fifty-nine dogs were treated at 8 institutions. Twenty-three tumor specimens were confirmed to be CD18 positive. Treatment with CCNU at 60 to 90 mg/m 2 resulted in an overall response rate of 46% in the 56 dogs with gross measurable disease. All 3 dogs with minimal residual disease experienced tumor relapse but lived 433 days or more after starting CCNU. The median survival of all 59 dogs was 106 days. Thrombocytopenia (,100,000 platelets/mL) and hypoalbuminemia were found to be negatively associated with prognosis and were predictive of ,1 month survival.Conclusions and Clinical Importance: Results suggest that CCNU is active against canine histiocytic sarcoma and may be useful in the treatment of dogs without negative prognostic factors.

Abstract. Case information and histologic slides for 688 admissions of feline tissues from 12 veterinary institutions were assembled and reviewed to determine tissues obtained by biopsy or necropsy, age and sex of cat, tumor topography, feline leukemia viral antigen status, histologic frequency of mitoses, diagnosis, presence of necrosis, and presence and degree of sclerosis. Histologic sections were examined to place the lesions in one of the diagnostic categories of the National Cancer Institute working formulation (NCI WF) for lymphomas or lymphoid leukemia. Correlations between the various factors determined were tested using contingency tables and chi-square analysis to provide a statistical comparison between the levels of observations determined by case examination with the numbers expected from chance alone. Significant correlations (P Յ 0.05) were found between diagnosis and tumor topography, the frequency of mitoses, necrosis, sclerosis, and age, between mitoses and necrosis, topography, age, and feline leukemia viral infection status, between topography and necrosis and age, and between leukemia viral status and age. Significant correlations between diagnosis and tumor topography included a greater than expected number of cases of acute and chronic lymphoid leukemia and multicentric distribution of tumor. Small cell lymphomas were more frequent than expected in enteric and cutaneous areas and less frequent than expected in mediastinal, renal, and multicentric areas. In contrast, the high-grade small noncleaved type of lymphomas was found significantly more frequently than expected in the mediastinum and less frequently than expected in enteric tissues. In comparing diagnosis and frequency of mitoses, the lymphomas classified as low grade by the NCI WF were significantly more frequent than expected in the lower categories (0-2/100ϫ) of mitoses, and those classified as high-grade lymphomas were more frequent than expected in the higher categories (4-8/100ϫ) of mitoses. In comparing diagnosis and sclerosis, diffuse sclerosis was more frequent than expected for the intermediate grade lymphomas of mixed cell type and for the highgrade lymphomas of the immunoblastic polymorphous type. In comparing diagnosis and locally extensive necrosis, this feature was more frequently observed than expected for cases of intermediate grade lymphoma of the small-cleaved cell category and for the high-grade lymphoma of the immunoblastic cell type. In comparing mitoses and necrosis, the lower grade lymphomas were, in general, characterized by a lower frequency of mitoses and a lower incidence of necrosis then would be expected from chance alone. In contrast, the higher grade lymphomas were characterized by more frequent mitoses and a higher incidence of necrosis. In tests comparing mitoses and tumor topography, lymphomas of the alimentary tract were more frequently observed than expected in the category with the lowest level of mitoses (0-1/100ϫ), whereas lymphomas of the mediastinum and kidney were more frequently observed ...

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Hemangiosarcomas confined to the skin and underlying muscle were surgically excised in 2 5 dogs. Tumors were staged based on their histological location (ie, dermal, hypodermal, and deep). Dermal (stage I) hemangiosarcomas were small, most commonly ventral-abdominal or prepucia1 in location, and were associated with prolonged survival times (median survival, 780 days). Tumors with hypodermal (stage II) and underlying muscular involvement (stage 111) were grouped together because of their larger size, bruise-like appearance, lack of anatomic predilection, emangiosarcoma (HSA, malignant hemangioendo-H thelioma, angiosarcoma) is a neoplasm arising from endothelial cells.' It occurs more frequently in the dog than in any other species, with a reported prevalence of 0.3% to 2.0%.2-6 The spleen is the most frequent primary site of involvement; however, primary dermal and hypodermal HSAs are also common, accounting for 14% of these tumors in There are few reports specifically describing the biological behavior of HSAs originating from cutaneous (ie, dermal or hypodermal) tissues in dogs."-" Most cutaneous forms are included in the literature as part ofa large series ofdogs with HSAs, regardless of the tissue of rigi in.^,','^-^^ Frequently, it is difficult to distinguish cutaneous HSA from HSA of other origins (eg, splenic, right atrial) in these reports. The presence of 1 or more cutaneous HSAs may represent metastatic disease rather than a primary lesion, and therefore has frequently been associated with a poor prognosis." Cutaneous HSAs are rare in humans, in whom they have been described as highly invasive neoplasms with a high rate of local recurrence.23 They occur almost exclusively in I of 3 separate clinical presentations: ( 1) previously irradiated skin; ( 2 ) the face and scalp of elderly patients; and (3) the chronic lymphedematous extremity, often in postmastectomy patients.24 The long-term prognosis for these patients is extremely poor, with a reported median survival time of only 20 months after radical surgxal excision and adjuvant radiotherapy.25 The only two prognostic factors identified in humans with cutaneous HSA include the size of the lesion at the time of diagnosis and the degree of lymphocytic infiltration around the t~m o r .~~,~~ Tumors less than 5 cm in diameter and those with lymphocytic infiltrates are associated with longer survival times.",26Vascular stasis, radiation therapy, trauma, and sun exposure have been suggested as predisposing factors for the development of cutaneous HSAs in humans.26 Solar radiation has been proposed to play a causal role in spontaneously occumng dermal HSAs in dogs.'' In addition, HSAs have been experimentally induced with UV radiation in dogs2'The purpose of this study is to describe the clinical characteristics and survival times in dogs with primary cutaneous HSAs treated by surgical excision. Materials and MethodsRecords of the University of Florida and The Ohio State University veterinary pathology services were reviewed to identify all pribiological beha...

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Osteosarcoma is a debilitating bone cancer that affects humans, especially children and adolescents. A homologous form of osteosarcoma spontaneously occurs in dogs, and its differential incidence observed across breeds allows for the investigation of tumor mutations in the context of multiple genetic backgrounds. Using whole-exome sequencing and dogs from three susceptible breeds (22 golden retrievers, 21 Rottweilers, and 23 greyhounds), we found that osteosarcoma tumors show a high frequency of somatic copy-number alterations (SCNA), affecting key oncogenes and tumor-suppressor genes. The across-breed results are similar to what has been observed for human osteosarcoma, but the disease frequency and somatic mutation counts vary in the three breeds. For all breeds, three mutational signatures (one of which has not been previously reported) and 11 significantly mutated genes were identified. was the most frequently altered gene (83% of dogs have either mutations or SCNA in), recapitulating observations in human osteosarcoma. The second most frequently mutated gene, histone methyltransferase , has known roles in multiple cancers, but has not previously been strongly implicated in osteosarcoma. This study points to the likely importance of histone modifications in osteosarcoma and highlights the strong genetic similarities between human and dog osteosarcoma, suggesting that canine osteosarcoma may serve as an excellent model for developing treatment strategies in both species. Canine osteosarcoma genomics identify SETD2 as a possible oncogenic driver of osteosarcoma, and findings establish the canine model as a useful comparative model for the corresponding human disease. .

The clinical and pathologic features of systemic mastocytosis in 16 dogs are reported. There was no apparent breed or sex predilection, and the median age at presentation was 9.5 years. In 14 of 16 cases there was a primary cutaneous mast cell tumor (MCT). When cutaneous tumor location was compared with previous reports, there was no association between location and systemic dissemination. The most common presenting signs associated with the cutaneous tumor were regional dissemination, edema, ulceration, and abscessation. They were present in 12 dogs (69%). Signs of systemic illness, including anorexia, vomiting, and diarrhea, were seen in eight dogs (50%). Other than the cutaneous tumors, the most consistent physical and radiographic abnormalities included lymphadenopathy, splenomegaly, and hepatomegaly. Eosinophilia and basophilia were seen in two and five dogs, respectively. Six dogs had increased numbers of mast cells in peripheral blood or buffy coat smears. Five of the nine dogs evaluated had increased numbers of mast cells in bone marrow aspirates. Bone marrow aspiration was superior to both peripheral blood and buffy coat smears in predicting mastocytosis. Coagulation abnormalities were seen in three of five dogs tested.Using a conventional histomorphologic grading system, 10 of 13 (77%) tumors were classified as Grade 111 or undifferentiated and were overrepresented when compared with previous reports of cutaneous M a s . Eighty-eight percent of the dogs either died or were euthanatized because of their tumors. Organs commonly involved at necropsy included lymph nodes, spleen, liver, and bone marrow; four dogs had gastroduodenal ulcers. (Journal of Veterinary Internal Medicine 1987; 1:75-80)