Dendritic cell leukemia in a Golden Retriever

An 8-year-old castrated male Golden Retriever was evaluated for decreased appetite, lethargy, and labored breathing of 1-week duration. Bilateral pulmonary infiltrates, hepatomegaly, and splenomegaly were present. Results of a CBC revealed marked leukocytosis (62,600/microL; reference interval 4000-15,500/microL) and large numbers of atypical cells (30,700/microL) with abundant cytoplasm. There was no concurrent anemia, neutropenia, or thrombocytopenia. Morphology of the atypical cells was most consistent with a histiocytic origin. Similar cells were identified in bone marrow aspirates, and were morphologically suggestive of the macrophage variant of disseminated histiocytic sarcoma. However, flow cytometry of the abnormal circulating cells revealed CD1c, CD11c, and major histocompatibility complex (MHC) Class II expression without expression of CD11d or lymphoid markers, consistent with myeloid dendritic antigen-presenting cells. At necropsy, the splenic architecture was effaced by neoplastic histiocytes that were also infiltrating lung, liver, an abdominal lymph node, myocardium, an bone marrow. Immunohistochemistry of the splenic neoplastic cells confirmed dendritic cell origin (CD1c+, CD11c+, MHC II+, no expression of CD11d and lymphoid markers). To the authors' knowledge, this is the first report of canine dendritic cell leukemia-in this instance accompanied by marked tissue infiltration.     

Multifocal cutaneous histiocytic sarcoma in a young dog and review of histiocytic cell immunophenotyping

A 9‐month‐old male Great Dane had progressive generalized nodular dermatopathy for several months. There were > 100 raised, alopecic, firm, painful nodules throughout the skin. Aspirates from several lesions yielded moderate numbers of irregularly round or polygonal to spindle‐shaped cells with mild to moderate anisocytosis and few inflammatory cells, and the cytologic interpretation was proliferation of mesenchymal or histiocytic cells. On histopathologic examination, nodules were composed of densely packed sheets of round to spindle‐shaped cells with mild anisokaryosis and low mitotic activity. Multifocal histiocytic sarcoma with a spindle‐cell pattern was diagnosed based on morphologic features and intense expression of CD18. Additional immunophenotypic analysis on frozen sections of tissue confirmed the diagnosis of histiocytic sarcoma; expression of CD18, CD45, CD1a, CD11b, and CD11c, limited expression of Thy‐1 (CD90) and CD80, and lack of expression of CD4, CD11d, and CD86 indicated that the cells were likely interstitial dendritic cells; a review of reactive and neoplastic dendritic cells is provided. Based on staging, internal organs were not affected. Sequential treatment with lomustine and doxorubicin failed to prevent progression of the cutaneous lesions, and the dog died 3 months after initial diagnosis. At necropsy, a focus of neoplastic cells was present in one lymph node, but except for skin other organs were not involved. The clinical presentation of histiocytic sarcoma may be unusual, and neoplastic cells may lack overt features of malignancy on cytologic and histopathologic examination. In some instances, immunophenotyping is required to differentiate histiocytic sarcoma from other histiocytic disorders.     

A comparative pathological study on granulomatous meningoencephalomyelitis and central malignant histiocytosis in dogs

Histiocytic proliferative disorders in canine central nervous system (CNS) including granulomatous meningoencephalomyelitis (GME) and malignant histiocytosis were compared pathologically. Lesions of GME mainly existed in the white matter of the cerebrum, brainstem and cerebellum and consisted of characteristic perivascular cuffing, parenchymal granuloma and leptomeningeal infiltrates of mononuclear cells. In malignant histiocytosis, there were two histological patterns, diffuse proliferation of neoplastic histiocytes through the leptomeninges and neoplastic nodule formation in the parenchyma. Neoplastic histiocytes exhibited mild to severe cellular atypia and high ability of invasion into the brain parenchyma. Mitotic and phagocytic figures were also observed. Several histiocytic markers, including lysozyme, alpha1-antitrypsin and lectin RCA-1, revealed histiocytic origin of both inflammatory and neoplastic cells, however, those were not determinative for the discrimination between GME and malignant histiocytosis. CD3- and PCNA-positive cells existed in the lesions of both diseases. The number of CD3-positive cells in GME tended to be greater than in malignant histiocytosis, while the difference was not statistically significant.     

Localized and disseminated histiocytic sarcoma of dendritic cell origin in dogs

Canine histiocytic proliferative disorders include a wide spectrum of diseases characterized by different biologic behaviors. The etiology and pathogenesis of these diseases are largely unknown. The clinicopathologic, morphologic and immunophenotypic characteristics of canine localized and disseminated histiocytic sarcoma were examined in 39 dogs. Rottweilers, Bernese Mountain Dogs, and retrievers were most commonly affected (79%). Localized histiocytic sarcomas (19 dogs) arose from a single site, and metastatic lesions were observed in draining lymph nodes. Predilection sites were subcutis and underlying tissues on extremities, but tumors occurred in other locations, including spleen, lung, brain, nasal cavity, and bone marrow. Disseminated histiocytic sarcomas (20 dogs), a multisystem disease previously described as malignant histiocytosis, primarily affected spleen, lungs, bone marrow, liver, and lymph nodes. Both localized and disseminated canine histiocytic sarcomas were composed of pleomorphic tumor cell populations. CD1+, CD4-, CD11c+, CD11d-, MHC II+, ICAM-1 +, Thy-1 +/- tumor cells were identified in all snap-frozen samples (31 dogs). This phenotype is characteristic for myeloid dendritic antigen-presenting cell lineage. Hence, canine localized and disseminated histiocytic sarcomas are likely myeloid dendritic cell sarcomas. Dendritic antigen-presenting cells are a heterogeneous cell population with regards to their ontogeny, phenotype, function, and localization. The exact sublineage of the proliferating dendritic antigen-presenting cells involved in canine histiocytic sarcomas remains to be determined. Phenotypic analysis of formalin-fixed tissues from eight dogs was limited by available markers. Morphologic features and the phenotype CD18+, CD3-, and CD79a- were the most useful criteria to indicate likely histiocytic origin.     

Paraneoplastic hypereosinophilia in a dog with intestinal T-cell lymphoma

A 9-year-old, intact male Doberman Pinscher was examined because of anorexia and weakness. Results of a CBC showed severe, microcytic, hypochromic anemia with mild eosinophilia (2944 cells/microL, reference interval 100-1250/microL) and thrombocytosis. Hypoferremia, hypoferritinemia, and a positive fecal occult blood test supported a diagnosis of iron deficiency anemia secondary to chronic intestinal hemorrhage. Abdominal ultrasound evaluation showed a thickened small intestinal loop, of which representative specimens were obtained during exploratory laparotomy. Histologically, the intestinal wall was infiltrated by a neoplastic population of large, round, lymphoid cells with vesicular chromatin, 1 or more prominent nucleoli, and a high number of mitotic figures. The cells were closely admixed with mature eosinophils, but were negative for metachromatic granules with toluidine blue. Immunohistochemically, tumor cells were positive for CD3, and negative for CD21, Pan B, and CD79a. A diagnosis of intestinal T-cell lymphoma was made. Chemotherapy was begun, with 30 mg/m;2 of doxorubicin administered intravenously every 3 weeks. Eosinophil concentration was 880/microL 2 weeks after surgery (on day 15 after presentation) but increased markedly to 62,914/microL on day 30, 62,400/microL on day 37, and 39,444/microL on day 58 after presentation. An association between hypereosinophilia and T-cell lymphoma is well established in human patients, in whom production of IL-5 by neoplastic T cells has been demonstrated. Hypereosinophilia has been reported only rarely with intestinal lymphoma in cats and horses, and with T-cell lymphoma in dogs.     

Malignant fibrous histiocytoma in a Djungarian hamster

A subcutaneous malignant fibrous histiocytoma (MFH) was observed in the region between the right posterior trunk and right hind limb of a 2-year-old male Djungarian hamster weighing 45 g. Histologically, the tumor consisted of bizarre multinucleated giant cells, histiocytic cells, and fibroblastic cells with a storiform pattern, and was considered to be of the storiform-pleomorphic type of MFH. Severe nuclear atypia with prominent nucleoli and many mitotic figures was also observed. Electron microscopy demonstrated fibroblastic cells and histiocytic cells. The fibroblastic cells were spindle-shaped, and sometimes had an invaginated nucleus. The histiocytic cells were polygonal with an oval or kidney-shaped nucleus. The cytoplasm of both cells contained numerous free ribosomes, small amounts of rough endoplasmic reticulum, and round mitochondria. Tumor cells were immunohistochemically positive for vimentin, and were thought to be of undifferentiated mesenchymal cell origin. This is the first report of spontaneous MFH in a hamster.     

Diffuse leptomeningeal malignant histiocytosis in the brain and spinal cord of a Tibetan Terrier

An 8-year-old male Tibetan Terrier showed prolonged astasia, complete paralysis, ticlike signs, and seizure and died 2 months after the onset of symptoms. Histopathologically, there was moderate to severe infiltration of pleomorphic histiocytic mononuclear cells bilaterally in the basiarachnoidal and ventricular areas of the brain. The spinal dura mater, arachnoidal space, and leptomeninges were also affected by infiltrative proliferation of these mononuclear cells. The infiltrating cells had the morphologic characteristics of histiocytes but exhibited moderate pleomorphism and atypia, with abundant mitotic figures. With immunohistochemistry and lectin histochemistry, most of the infiltrating cells were positive for lysozyme and lectin RCA-1 and negative for glial fibrillary acid protein, suggesting that they were of monocytic/histiocytic-origin. Positive proliferating cell nuclear antigen immunostaining demonstrated that most nuclei of the histiocytic cells were in the S phase of the cell cycle, consistent with a proliferating population of cells. Based on these findings, the case was diagnosed as diffuse leptomeningeal malignant histiocytosis.     

Clinical, cerebrospinal fluid, and histological data from thirty-four cats with primary noninflammatory disease of the central nervous system.

The purpose of this study was to report the clinical, cerebrospinal fluid (CSF), and histological data derived from a study of 34 cats with noninflammatory central nervous system (CNS) disease, and to report the activities of the enzymes lactate-dehydrogenase (LDH), aspartate transferase (AST), and creatine kinase (CK) in the CSF from 15 cats with a variety of CNS diseases. The cats were part of a study of 61 cats that were admitted to two university clinics because of signs of CNS disease. The most frequent noninflammatory diseases were neoplasia (n = 12) and ischemic encephalopathy (n = 4). The majority of cats with CNS neoplasia had a mild increase in CSF protein concentration (less than 1 g/L [100 mg/dL]), an increased percentage of neutrophils or lymphocytes, and a normal total white cell count. Cats with ischemic encephalopathy (IE) had a mild to moderate increase in CSF protein concentration (< or = 2 g/L [200 mg/dL]) and a mild increase in white cell count (< or = 10 cells/microL) with an increased percentage of lymphocytes. The enzymes LDH, AST, and CK in the CSF were not sensitive indicators of chronic CNS disease. The CSF differential cell count was frequently abnormal when the total white cell count was normal, and blood contamination in the CSF samples was a frequent problem that had to be considered in the interpretation of the results. The history, signalment, and clinical signs, when combined with the CSF findings, were valuable in the diagnosis of noninflammatory CNS disease.     

Presumptive increase in protein‐bound serum calcium in a dog with multiple myeloma

Abstract: An 11‐year‐old male castrated Australian Shepherd was presented with a history of lethargy, panting, and weight loss for 1 month. Physical examination revealed a moderately enlarged spleen. Laboratory abnormalities included thrombocytopenia and marked hypercalcemia, with hyperglobulinemia, hypoalbuminemia, and a monoclonal spike in the β‐globulin region on serum protein electrophoresis. Serum total calcium concentration was markedly increased (16.5 mg/dL, reference interval 8.9–11.4 mg/dL) but ionized calcium concentration (1.39 mmol/L) was within the reference interval (1.25–1.45 mmol/L). Isosthenuria was noted, but the dog was not polyuric or polydipsic. Serum parathyroid hormone concentration was within reference limits and parathyroid hormone‐related peptide concentration was 0 pmol/L. Radiographic findings were largely unremarkable. Results of cytologic evaluation of a fine‐needle aspirate specimen from the spleen indicated plasma cell neoplasia. Based on the results of the electrophoresis, splenic aspirates, radiographs, and hypercalcemia, a diagnosis of splenic multiple myeloma was made. The marked hypercalcemia, normal ionized calcium and parathyroid hormone concentrations, and lack of osteolytic lesions indicated a presumptive increase in protein‐bound serum calcium, likely due to binding to molecules of the paraprotein (M protein). Protein binding of calcium in dogs with multiple myeloma should be considered as a potential mechanism of elevated total serum calcium concentration.     

Diagnostic assessment of peritoneal fluid cytology in horses with abdominal neoplasia

Objective: To evaluate the diagnostic value of peritoneal fluid (PF) cytology for clinical diagnosis of abdominal neoplasia in horses. Material and methods: Ten horses with histopathologically confirmed abdominal neoplasia, in which a PF analysis was performed, were included in this retrospective study. PF was analyzed for total protein concentration and a nucleated cell count was performed. Using cytological criteria of malignancy, the PF samples were evaluated regarding their probability of malignancy. Results: Cytologic classification of cells according to criteria of malignancy allowed a positive cytologic diagnosis of neoplasia in 5 out of 10 peritoneal fluid samples. Malignant lymphoma was the most commonly diagnosed neoplasia (3/10) and could be identified by cytology in 2/3 cases. In 1/2 horses with plasma cell myeloma neoplastic cells were similarly found. Malignant melanoma (2/10) was diagnosed using cytology in one case (presence of melanin-containing cells). Cytological diagnosis of malignant neoplasia was established in the only horse with gastric squamous cell carcinoma, but the morphology of the identified tumour cells did not allow a specific diagnosis. Thus, a definitive diagnosis was achieved in 4/5 horses with proven abdominal neoplasia. The horses with adenocarcinoma (1/10) and haemangiosarcoma (1/10) had no evidence of neoplasia based on cytological findings. No relationship between total protein concentration or the nucleated cell count with the histolopathological diagnosis of abdominal neoplasia was found. Abnormal mitotic figures were considered of greater diagnostic value than the overall mitotic rate. Conclusion: The implementation of nuclear criteria of malignancy in the cytologic evaluation of PF samples allows the identification of neoplastic cells to an acceptable degree. For this purpose, the knowledge of the highly variable morphological features of mesothelial cells is essential. The absence of malignant cells does not rule out abdominal neoplasia. Clinical relevance: PF cytology should be considered as a valuable, minimally invasive, simple, and rapid diagnostic technique in horses with suspected abdominal neoplasia.     

Clinical, cerebrospinal fluid, and histological data from twenty-seven cats with primary inflammatory disease of the central nervous system.

The purpose of this report is to present the clinical, cerebrospinal fluid (CSF) and histological data from 27 cats with inflammatory disease of the central nervous system (CNS). The cats were part of a study of 61 cats admitted to two university clinics over an eight-year period because of signs of CNS disease. The most frequent diseases were feline infectious peritonitis (FIP) (12/27) and suspected viral disease other than FIP (10/27). Typical CSF findings in cats with FIP were a protein concentration of greater than 2 g/L (200 mg/dL) and a white cell count of over 100 cells/microL, which consisted predominantly of neutrophils. In contrast, the CSF of cats with suspected viral disease had a protein concentration of less than 1 g/L (100 mg/dL) and a total white cell count of less than 50 cells/microL. In general, cats with FIP or suspected viral disease were less than four years of age. Neurological signs were usually multifocal in cats with FIP, but focal in cats with suspected viral disease. The CSF findings were variable in five other inflammatory diseases represented. Two cats with protozoan infection had normal CSF total cell counts but abnormal differential counts. The CSF findings were invaluable in differentiating FIP from other causes of inflammatory CNS disease.     

Hematology and plasma chemistry reference intervals for cultured shortnose sturgeon (Acipenser brevirostrum)

BACKGROUND: The shortnose sturgeon, Acipenser brevirostrum, is an imperiled species distributed along the Atlantic coast of North America. Interest in replenishing wild stocks with hatchery-reared fish has created a need for accurate hematologic and biochemical reference intervals to evaluate the health of both fish raised in aquaculture systems and fish in the wild. OBJECTIVES: The objective of this study was to generate hematologic and biochemistry reference intervals for healthy shortnose sturgeon. METHODS: Blood samples were collected in heparinized tubes from 77 shortnose sturgeon raised in flow-through aquaculture systems. Whole blood and plasma samples were analyzed for hematologic and biochemical variables using standard techniques. Reference intervals were calculated as the central 95% (percentile) of data. RESULTS: Hematologic reference intervals (n = 46) were as follows: PCV 26-46%, hemoglobin 5.7-8.7 g/dL, MCV 307-520 fL, MCH 65.9-107.1 pg, MCHC 15-30 g/dL, plasma proteins (refractometry) 2.8-6.0 g/dL, RBC count 0.65-1.09 x 10(6)/microL, total WBC count 28,376-90,789/microL, small lymphocytes 9063-56,656/microL, large lymphocytes 2122-10,435/microL, neutrophils 3758-33,592/microL, monocytes 0-7137/microL, eosinophils 0-1544/microL, thrombocyte-like cells 6863-23,046/microL, thrombocytes 32,205-122,179/microL, and neutrophil:lymphocyte ratio 0.068-1.026. Plasma chemistry reference intervals (n = 77) were as follows: total protein 2.7-5.3 g/dL, albumin 0.8-1.7 g/dL, globulins 1.8-3.7 mg/dL, creatinine 0-1.4 mg/dL, total bilirubin 0-0.1 mg/dL, alkaline phosphatase 47-497 U/L, aspartate aminotransferase 90-311 U/L, sodium 124-141 mmol/L, potassium 2.9-3.7 mmol/L, chloride 106-121 mmol/L, calcium 6.6-12.1 mg/dL, magnesium 1.6-2.3 mg/dL, phosphorus 5.1-8.1 mg/dL, glucose 37-74 mg/dL, cholesterol 42-133 mg/dL, and osmolality 232-289 mOsm/kg. CONCLUSION: Reference values reported here will be useful for the early detection, identification, and monitoring of disease and sublethal conditions in cultured shortnose sturgeon.     

Composition of cerebrospinal fluid in clinically normal adult ferrets

OBJECTIVE: To determine the protein and cellular composition of CSF in healthy adult ferrets. ANIMALS: 42 clinically normal adult ferrets. PROCEDURE: CSF samples were collected from the cerebellomedullary cistern of anesthetized ferrets by use of disposable 25-gauge, 1.6-cm-long hypodermic needles. Samples were processed within 20 minutes after collection. The number of WBCs and RBCs per microliter of CSF was counted by use of a hemacytometer. The total protein concentration was determined by use of an automated chemistry analyzer. RESULTS: Total WBC counts (range, 0 to 8 cells/microL; mean, 1.59 cells/microL) in CSF of ferrets were similar to reference range values obtained for CSF from other species. Twenty-seven CSF samples had <100 RBCs/microL (mean, 20.3 RBCs/microL). A small but significant effect of blood contamination on WBC counts was found between the 27 CSF samples with <100 RBCs/microL and the remaining samples. Protein concentrations in CSF of ferrets (range, 28.0 to 68.0 mg/dL; mean, 31.4 mg/dL) were higher than has been reported for the CSF of dogs and cats. A significant effect of blood contamination on the CSF protein concentration was not found. CONCLUSION AND CLINICAL RELEVANCE: We have established reference range values for WBC counts and protein concentrations in CSF from healthy adult ferrets that may be useful in the clinical investigation of CNS disease. Results of our study indicate that the WBC count is significantly affected by blood contamination of the CSF sample.     

Of all the nerve! A subcutaneous forelimb mass on a cat

A 16-year-old, male, neutered cat had a 2.5 X 1.5 cm mass on the medial aspect of the right carpus. Cytologic examination of a fine-needle aspirate of the mass indicated a markedly pleomorphic population of plasmacytoid to histiocytic-appearing cells. The cytologic diagnosis was malignant neoplasia of probable mesenchymal or round cell origin. The right forelimb was surgically removed and the scapular, axillary, and prescapular lymph nodes were excised. Malignant fibrous histiocytoma was tentatively diagnosed histologically; however, the tumor cells subsequently were found to be negative for histiocytic (MAC 387, antitrypsin), T-cell (CD3), and B-lymphocyte (immunoglobulin light chains, Ly 5/CD45R) markers, and positive for glial fibrillary acidic protein, vimentin, and S-100. Based on the immunohistochemical results, the diagnosis was modified to malignant peripheral nerve sheath tumor (PNST). Six months after surgery, the cat was reported to be well and had no evidence of metastasis. PNSTs are rare tumors in cats, and are considered as synonymous with schwannomas, neurofibrosarcomas, and hemangiopericytomas. In this cat, the plasmacytoid and pleomorphic appearance of the PNSTcells in cytologic and histologic specimens was unusual, and made it difficult to reach an accurate diagnosis without immunocytochemistry.     

Malignant histiocytosis in a domestic cat: cytomorphologic and immunohistochemical features

Malignant histiocytosis (MH) was diagnosed in a 13-year-old neutered male Domestic Shorthair cat on the basis of light microscopic and immunohistochemical findings. Thoracic fluid analysis showed a modified transudate which contained a very few atypical discrete cells. Cytologic and histologic evaluation of mediastinal and splenic masses revealed a pleomorphic population of large, discrete, round cells 10 to 30 micrometers in diameter with marked cellular atypia. Nuclei were oval to reniform, often with prominent, bizarre nucleoli. Multinucleated cells and mitotic figures were commonly seen. Erythro- and leucocytophagia were noted. Immunohistochemistry indicated a scattered positive staining pattern with the histiocytic antigenic marker Mac387 and a minor population of cells showing positive reactivity for lysozyme. This report describes the characterization of MH in a cat and emphasizes that MH should be considered as a differential diagnosis in proliferative disorders of discrete-cells in this species.     

Canine hemophagocytic histiocytic sarcoma: a proliferative disorder of CD11d+ macrophages

Histiocytic disorders of dogs include histiocytoma, localized histiocytic sarcoma (HS), disseminated HS (malignant histocytosis), and the reactive histiocytoses: cutaneous and systemic. A common element to these diseases is proliferation of dendritic cells (DC) of either Langerhans cell (epithelial DC) or interstitial DC lineage. In this report, 17 dogs with hemophagocytic HS are described. Breeds affected included Bernese Mountain Dog (6), Golden Retriever (4), Rottweiler (3), Labrador Retriever (2), a mixed-breed dog, and a Schnauzer, which were from 2.5 to 13 years old. The dogs presented with Coombs negative responsive anemia in 16/17 dogs (94%), thrombocytopenia in 15/17 dogs (88%), hypoalbuminemia in 16/17 dogs (94%), and hypocholesterolemia in 11/16 dogs (69%). All dogs died or were euthanized. The clinical course ranged from 2 to 32 weeks (mean 7.1 weeks). Diffuse splenomegaly with ill-defined masses was consistently present. Microscopic lesions were prevalent in spleen, liver, lung, and bone marrow. Metastasis occurred by insidious intravascular invasion with minimal mass formation. Histiocytes were markedly erythrophagocytic and accompanied by foci of extramedullary hemopoiesis. Cytologically, the histiocytes varied from well differentiated to atypical, with atypia more prevalent in spleen than bone marrow. These tumors arose from splenic red pulp and bone marrow macrophages, which expressed major histocompatibility complex class II and the beta2 integrin, CD11d. They had low and/or inconsistent expression of CD1 and CD11c, which are dominantly expressed by canine nonhemophagocytic HS of DC origin. Canine histiocytic proliferative diseases now encompass proliferation of all members of the myeloid histiocytic lineage: Langerhans cells, interstitial DC, and macrophages.     

D-lactic acidosis secondary to exocrine pancreatic insufficiency in a cat

An indoor, 2-year-old, spayed female domestic cat was referred to the University of Missouri Veterinary Medical Teaching Hospital (UMC-VMTH) for evaluation of weight loss and polyphagia of 1-year duration, with recent episodes of generalized weakness and lethargy. These episodes occurred approximately once per month over the past 4 months. The cat produced frequent stools, which were occasionally poorly formed. A CBC and serum biochemistry were performed 1 and 5 months before referral, and leukopenia (1,200/μL; reference interval, 3,500-16,000/μL; no differential provided), hypocholesterolemia (64 mg/dL and 46 mg/dL; reference interval, 75–220 mg/ dL), and hypotriglyceridemia (22 mg/dL and 16 mg/dL; reference interval, 26–160 mg/dL) were identified. The most recent serum biochemistry results disclosed mild hypercalcemia (11.3 mg/dL; reference interval, 8.2–10.8 mg/ dL) and hypernatremia (163 mg/dL; reference interval, 145–158 mg/dL). Antibody titers for Toxoplasma were consistent with past exposure (immunoglobulin M [IgM] negative; IgG 1:256).     

CCNU for the treatment of dogs with histiocytic sarcoma

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/m2 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/microL) 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.     

Cytologic,histologic, and immunohistochemical features of maxillofacial alveolar rhabdomyosarcoma in a juvenile dog

Abstract: A 15‐month‐old castrated male dog with a history of intermittent epistaxis and sneezing was admitted for the examination of a maxillofacial mass. An impression smear of a biopsy sample from the cauliflower‐shaped gingival mass contained numerous round cells, 5–25 μm in diameter, which contained a moderate amount of clear to pale blue cytoplasm and resembled lymphoid cells. Mitotic figures were frequently observed. The mass was diagnosed as malignant round cell neoplasia. On histologic examination the tumor was composed of diffusely arranged, small, atypical round cells with a small amount of fibrovascular stroma. Immunohistochemically, the cells were negative for CD3, CD18, CD20, CD79α, cytokeratin, melan‐A, chromogranin A, α‐smooth muscle actin, and myoglobin but positive for vimentin and desmin. The cells also had strong positive nuclear staining for myogenin and MyoD1. A diagnosis of solid‐pattern alveolar rhabdomyosarcoma was made on the basis of morphologic and immunohistochemical results. Alveolar rhabdomyosarcoma should be considered in the differential diagnosis of tumors in juvenile dogs, especially when cytologic findings reveal round, undifferentiated cells.     

Collection and analysis of peritoneal fluid from healthy llamas and alpacas

OBJECTIVE: To describe a technique for abdominocentesis in camelids and report peritoneal fluid biochemical and cytologic findings from healthy llamas and alpacas. DESIGN: Prospective study. Animals-17 adult llamas and 5 adult alpacas. PROCEDURES: Right paracostal abdominocentesis was performed. Peritoneal fluid was collected by gravity flow into tubes containing potassium-EDTA for cell count and cytologic evaluation and lithium heparin for biochemical analysis. Blood samples were collected via jugular venipuncture into heparinized tubes at the same time. Cytologic components were quantified. Fluid pH and concentrations of total carbon dioxide, sodium, potassium, chloride, lactate, and glucose were compared between peritoneal fluid and venous blood. RESULTS: All but 3 camelids had peritoneal fluid cell counts of < 3,000 nucleated cells/microL, with < 2,000 neutrophils/microL and < 1,040 large mononuclear cells/microL. All but 1 had peritoneal fluid protein concentrations of > or = 2.5 g/dL. Peritoneal fluid of camelids generally contained slightly less glucose, lactate, and sodium and roughly equal concentrations of potassium and chloride as venous blood. CONCLUSIONS AND CLINICAL RELEVANCE: Peritoneal fluid was collected safely from healthy camelids. Compared with blood, peritoneal fluid usually had a low cell count and protein concentration, but some individuals had higher values. Electrolyte concentrations resembled those found in blood. High cell counts and protein concentrations found in peritoneal fluid of some healthy camelids may overlap with values found in diseased camelids, complicating interpretation of peritoneal fluid values.