Mammary gland carcinoma in a dog with peripheral blood and bone marrow involvement associated with disseminated intravascular coagulation

A 7-year-old female Leonberger dog was referred to the National Veterinary School of Lyon Teaching Hospital with a 2-day history of anorexia and bleeding. A mammary mass had been removed 7 months earlier, but histologic examination was not performed. On physical examination, the dog was depressed and had pale mucous membranes and numerous petechiae and hematomas. Significant laboratory findings were moderate thrombocytopenia, prolonged prothrombin, activated partial thromboplastin, and thrombin times, hypofibrinogenemia, and increased concentration of fibrin(ogen) degradation products. A peripheral blood smear, buffy coat preparation, and bone marrow aspirate contained low numbers of large atypical cells that had moderate nuclear:cytoplasmic ratios, oval nuclei with multiple prominent nuclei, and basophilic cytoplasm with villous projections. A small nodule was found in the left inguinal mammary gland, and a fine-needle aspirate contained cells similar to those in blood and bone marrow. In samples of blood, bone marrow, and the mammary mass, the neoplastic cells were immunoreactive for cytokeratin. The diagnosis was mammary carcinoma with secondary disseminated intravascular coagulation (DIC) and disseminated tumor cells in bone marrow and circulating tumor cells in blood; this diagnosis was not confirmed by histopathologic examination. Owing to clinical deterioration and the poor prognosis, the dog was euthanized and a necropsy was not performed. This is the first report of a canine mammary carcinoma with circulating tumor cells and secondary DIC.     

Bone-invasive oral squamous cell carcinoma in cats: pathology and expression of parathyroid hormone-related protein

Feline oral squamous cell carcinoma (OSCC) is the most common oral tumor in cats. There is no effective treatment, and the average duration of survival after diagnosis is only 2 months. Feline OSCC is frequently associated with osteolysis; however, the mechanisms responsible are unknown. The objective of this study was to characterize the epidemiology and pathology of bone-invasive OSCC in cats and to determine the expression of select bone resorption agonists. In sum, 451 cases of feline OSCC were evaluated. There was no sex or breed predisposition, although there were more intact cats in the OSCC group compared to the control group. Gingiva was the most common site, followed by the sublingual region and tongue. Cats with lingual OSCC were younger (mean, 11.9 years) compared to cats with gingival OSCC (mean, 13.6 years). In addition to osteolysis, there was periosteal new bone formation, osseous metaplasia of tumor stroma, and direct apposition of OSCC to fragments of bone, suggestive of bone-binding behavior. Eighty-two cases were selected for immunohistochemical detection of parathyroid hormone-related protein (PTHrP). Specimens with osteolysis had increased PTHrP expression and nuclear localization, compared to OSCC without osteolysis. Thirty-eight biopsies of OSCC with osteolysis were evaluated for tumor necrosis factor α expression, and only 4 biopsies had such expression in a small proportion of tumor cells. Increased tumor expression of PTHrP and increased localization of PTHrP to the nucleus were associated with osteolysis and may play an important role in bone resorption and tumor invasion in cats with OSCC.     

A case of malignant melanoma,a possible primary site in the digit,with systemic metastasis in a mini-Rex

We report a case of systemic metastasis of malignant melanoma in a mini-Rex (Oryctolagus cuniculus). The animal presented with lameness of the right hind limb, swelling of popliteal lymph node, and a black mass on the first digit. Paralysis of hindlimbs and forelimbs, dysuria, and dysphagia progressed over time, and the rabbit died on day 35 from the first visit. At necropsy, many black lesions were observed in multiple organs including the marrow of most bones. Histopathologically, the tumor cells had highly atypical nuclei of various sizes and an abundant eosinophilic cytoplasm, and some cells contained melanin granules. These cells were positive for PNL2 and S-100, melanoma markers, by immunohistochemistry. This is the first report of malignant melanoma in a mini-Rex with severe malignancy and systemic metastasis including the bone marrow.     

Multiple myeloma in 16 cats: a retrospective study

BACKGROUND: There is limited published information regarding feline multiple myeloma. Diagnostic criteria are derived from canine studies and to our knowledge, have not been critically reviewed for cats. OBJECTIVE: To evaluate the clinical and laboratory findings in cats with multiple myeloma and appraise diagnostic criteria. METHODS: Retrospective evaluation of medical records was performed. Inclusion required an antemortem diagnosis of multiple myeloma using 2 of 4 criteria: 1) >or=20% plasma cells in the bone marrow, or >or=10% if atypical plasma cells; 2) paraproteinemia; 3) radiographically-evident osteolysis; 4) light chain proteinuria. Alternatively, a postmortem diagnosis was based on the findings of multiple plasma cell neoplasms, with marrow involvement. RESULTS: Sixteen cats were diagnosed with multiple myeloma between 1996 and 2004, with a median age of 14.0 years; 9 of 16 (56%) were castrated males, and 7 of 16 (44%) were spayed females. Laboratory abnormalities included hyperglobulinemia (14/16, 87.5%), with 11/14 (78.5%) monoclonal and 3/14 (21.4%) biclonal gammopathies; hypoalbuminemia (4/16, 25%); light chain proteinuria, (4/9, 44.4%); hypocholesterolemia (11/16, 68.7%); hypercalcemia, (3/15, 20%); nonregenerative anemia, (11/16, 68.7%); regenerative anemia, (1/16, 6.2%); neutropenia (5/15, 33.3%); thrombocytopenia (8/16, 50%); and marrow plasmacytosis (14/15, 93.3%). Plasma cells were markedly immature, atypical, or both in 10 of 12 (83.3%) cats. Focal or multifocal osteolysis was noted in 6 of 12 (50%) cats for which radiographs were available for review; generalized osteopenia was found in 1 (8.3%) cat. Noncutaneous, extramedullary tumors were found in all cats assessed, 7/7 (100%), including spleen (6), liver (3), and lymph nodes (4). The disease in 1 of 2 cats with cutaneous tumors progressed to plasmacytic leukemia. CONCLUSIONS: Common findings in feline multiple myeloma include atypical plasma cell morphology, hypocholesterolemia, anemia, bone lesions, and multi-organ involvement. Based on the results of this study, we advocate modifying diagnostic criteria in cats to include consideration of plasma cell morphology and visceral organ infiltration.     

Extranodal lymphoblastic lymphoma of suspected B-cell lineage in the gingiva of a racehorse,accompanied by mandibular osteolysis

A mass developed in the mandibular gingiva of a thoroughbred racehorse. When the horse could no longer eat unassisted, it was killed and immediately autopsied. Macroscopically, the mandible exhibited extensive osteolysis, with only a small amount of bone remaining around the tooth roots. The cut surface of the mass around the mandible consisted of neoplastic medullary tissue, in which osteogenesis was observed. The medullary tissue was composed of pleomorphic medium-sized to large cells, interlaced by collagen bundles. These cells had large, pale, round or ovoid, sometimes cleaved nuclei, with one or two prominent nucleoli. Mitoses were numerous. Electron microscopy showed that the cells in the medullary tissues were similar in shape to undifferentiated lymphocytes. Immunohistochemically, these cells were positive for B-cell associated antigen in the pre-B-cell stage. Our findings suggest that the horse had extranodal lymphoblastic lymphoma of suspected B-cell lineage, possibly originating from the lymphatic system of the gingiva. We consider that the osteolysis resulted from activation of osteoclasts by proliferation of the tumour cells.     

Blood and bone marrow findings in two pups with mucopolysaccharidosis type VII

Routine blood smear findings in two of four 11‐day‐old mixed‐breed dog littermates were suggestive of a lysosomal storage disease (LSD) that was documented to be mucopolysaccharidosis type VII (MPS VII) by molecular testing. In this condition, a functional β‐glucuronidase deficiency results in the accumulation of glycosaminoglycans (GAGs) in cells and tissues where β‐glucuronidase is important in GAG degradation. Most neutrophils and a moderate number of lymphocytes within the blood had atypical cytoplasmic magenta inclusions. The bone marrow assessment from one of the two affected pups at 24 days of age revealed similar magenta granulation in myeloid precursor cells that was most prominent in promyelocytes and myelocytes. Moreover, atypical magenta material was present within vacuoles as well as extracellularly in some osteoblasts and macrophages. Histologic bone marrow sections revealed prominent vacuolation of osteoblasts, and some osteoclasts appeared separated from the bone by layers of osteoblasts or hematopoietic cells. At 2 months of age, the second affected dog showed moderate growth retardation and had similar but more prominent hematologic findings that extended to monocytes, eosinophils, and eosinophil precursors. It had an increased number of bone marrow macrophages with many vacuoles that could be seen cytologically to contain magenta material, and there was mild nonselective phagocytosis of hemic cells. Of the hematologic cells, inclusions were most prominent in promyelocytes, myelocytes, and macrophages, cells with relatively high β‐glucuronidase activity, and GAG exposure within lysosomes or lysosome‐like primary granules of granulocyte precursors.     

Myeloma-related disorder with leukaemic progression in a cat

A 10-year-old American Shorthair cat with nasal discharge, anorexia, and weight loss was found to have pancytopenia and hyperproteinaemia. Bone marrow aspiration revealed atypical plasma cells that totalled 50% of the nucleated bone marrow cells. The number of atypical plasma cells progressively increased in the peripheral blood during the observation period of 64 days. The cat did not respond to treatments with melphalan, chlorambucil, and prednisolone, and died 71 days after the initial presentation. Clinical, cytological, histopathological, and immunohistochemical findings in this case supported the diagnosis of myeloma-related disorder (MRD) with leukaemic progression.     

A mixed apocrine gland tumor with metastases to the bone and bone marrow in a miniature poodle

A 10-year-old female miniature poodle had a mass in its carpal joint of the left forelimb. The tumor was divided into small multiple lobules by delicate connective tissues, and necroses were found in some of the central lobules. In some connective stromal areas, chondroid and osteoid tissues were formed. The tumor cells were similar to the structure of apocrine gland epithelial cells with apical blebs resembling apocrine secretion and eosinophilic secretary materials within the luminal space, and spindle cells were sometimes found in the basal area of the glandular structure. In some areas, tumor cells invaded in the blood vessels, bone and bone marrow. Immunohistochemically, the tumor cells forming tubulo-acinar to solid structures were intensely positive for cytokeratin and keratin K8/K18, and the spindle cells were positive for vimentin and alpha-smooth muscle actin. This case was diagnosed as a malignant mixed apocrine gland tumor with metastases to the bone and bone marrow.     

Lymphosarcoma with hypercalcemia and osteolysis in a dog

Lymphosarcoma in a six year old male Doberman pinscher was accompanied by hypercalcemia, generalized osteolysis and renal calcification. Tumor involvement of bone marrow was extensive. The possible pathogenesis of hypercalcemia was thought to be the result of a locally active bone-resorbing factor secreted by the tumor cells.     

Flow cytometric evaluation of hemophagocytic disorders in canine

Background — Hemophagocytic macrophages in canine bone marrow are observed in malignant histiocytosis as well as benign hemophagocytic histiocytosis. Cytomorphologic evaluation alone may be inadequate to consistently differentiate between benign and malignant forms of hemophagocytic disorders. Objective — The purpose of this study was to evaluate the ability of flow cytometry and immunophenotyping to differentiate between benign and malignant types of hemophagocytic disorders in dogs. Methods — Blood smears and bone marrow differential cell counts were evaluated for 10 dogs with hemophagocytic disorders. Bone marrow samples were labeled with monoclonal antibodies to CD18, MCH class‐II, Thy‐1, CD14, CD3, and CD21. Using flow cytometry, forward‐angle versus side‐angle light scatter plots were analyzed and immunophenotypes were determined. Results — Scatter plots from 3 dogs with a necropsy diagnosis of malignant histiocytosis revealed 2 atypical cell clusters. One cluster contained cells of similar size or larger than immature myeloid cells and metamyelocytes. Cells in the other cluster were highly granular, with granularity similar to or greater than that of metamyelocytes. In bone marrow from dogs with malignant histiocytosis that was labeled with anti‐CD14 antibody, macrophages represented 29–48% of nucleated cells. Seven dogs had a clinical or histopathologic diagnosis of benign hemophagocytic syndrome. Three of the dogs had normal cell distribution in scatter plots. Two dogs had 2 abnormal cell clusters: 1 within the immature myeloid and metamyelocyte gates and the other with granularity similar to or greater than that of metamyelocytes. The remaining 2 dogs had an atypical cell population, mostly within the immature myeloid gate. For dogs with benign hemophagocytic syndromes, 6–17% of cells in the bone marrow were CD14 positive. Conclusions — The cellular distribution in scatter plots and the total number of macrophages in bone marrow may be useful in differentiating malignant histiocytosis from benign hemophagocytic syndromes in dogs.     

Bone marrow necrosis and myelophthisis: manifestations of T‐cell lymphoma in a horse

Abstract: A 14‐year‐old spayed American Paint mare was evaluated for mild colic, anorexia, pyrexia, and pancytopenia. Physical examination revealed mild tachycardia, tachypnea, and pale mucous membranes. Serial laboratory analyses revealed progressive pancytopenia, hyperfibrinogenemia, and hyperglobulinemia. A few large atypical cells were observed in peripheral blood smears. Results of tests for equine infectious anemia and antipenicillin antibody were negative. Serum protein electrophoresis indicated a polyclonal gammopathy. Smears of bone marrow aspirates contained hypercellular particles, but cell lines could not be identified because the cells were karyolytic, with pale basophilic smudged nuclei and lack of cellular detail. A diagnosis of bone marrow necrosis was made. Treatment consisted of antimicrobials, nonsteroidal anti‐inflammatory drugs, and corticosteroids. The pyrexia resolved; however, the pancytopenia progressively worsened and petechiation and epistaxis developed. The horse was humanely euthanized. Postmortem examination revealed a diffuse round cell neoplasm infiltrating the kidneys, spleen, lymph nodes, lungs, and bone marrow. Immunophenotyping results (CD3+, CD79α−) indicated the neoplastic cells were of T‐cell lineage. Infiltration of lymphoma cells into the bone marrow appeared to have resulted in severe myelophthisis and bone marrow necrosis. Bone marrow necrosis has been associated previously with lymphoma in humans and dogs. To our knowledge, this is the first reported case of lymphoma resulting in bone marrow necrosis in a horse.     

Histopathology of canine bone marrow in malignant lymphoproliferative disorders

Bone marrow core biopsies from 63 dogs with malignant lymphoproliferative disorders and leukemic involvement were evaluated. Multicentric lymphoma (44), multiple myeloma (8), chronic lymphocytic leukemia (9), and acute lymphoblastic leukemia (2) were found. Four distinct bone marrow histologic patterns were identified: focal (6), mixed (20), interstitial (28), and packed (9). Of those with focal or mixed patterns, 77% (20/26) had paratrabecular distribution. Stromal changes were infrequent, with 6% (4/63) having necrosis, 3% (2/63) fibrosis, and 6% (4/63) osteolysis. For each condition, the interstitial and mixed patterns were the most common presentations, while focal and packed patterns occurred less frequently. Morphologically, cells of metastatic lesions of lymphoma resembled those of primary sites. Colonization of bone marrow by various cytologic types of lymphoma was independent of the histologic patterns.     

Cytologic evaluation of benign and malignant hemophagocytic disorders in canine bone marrow

Abstract: Canine hemophagocytic disorders were studied to better understand the cytologic features that differentiate benign and malignant disease. Of 286 canine clinical bone marrow reports evaluated retrospectively, 13 (4.5%) noted at least 3% hemophagocytic macrophages. Macrophages comprised between 6% and 44% of nucleated bone marrow cells. Clinical diagnoses for dogs with hemophagocytic disorders included malignant histiocytosis (n = 2), myelodysplastic syndromes (n = 4), round cell neoplasia (n = 2), immune-mediated disorders (n = 2), and idiopathic hemophagocytic syndrome (n = 3). Differentiation of benign and malignant forms of histiocytosis was problematic. Two dogs with a diagnosis of hemophagocytic syndrome had macrophages with atypical features similar to those described for malignant histiocytosis. Furthermore, only 2 of 11 dogs with presumably benign hemophagocytic disorders had exclusively mature macrophages in bone marrow. Other dogs had variable numbers of large reticular-type cells characterized by lacy chromatin, anisocytosis, anisokaryosis, and prominent and/or multiple nucleoli. On the basis of these results, cytomorphologic evaluation of bone marrow alone may not be adequate to consistently differentiate benign and malignant forms of hemophagocytic disorders.     

Cytologic evaluation of primary and secondary myelodysplastic syndromes in the dog

Myelodysplastic syndromes are a heterogeneous group of acquired primary and secondary alterations of hematopoietic stem cells that result in cytopenias in blood and cytologic features of dysplasia in blood and/or bone marrow. To better understand the cytologic features that would permit differentiation of primary and secondary forms of myelodysplasia, we reviewed 267 consecutive bone marrow reports from dogs. These reports indicated that 34 dogs (12.7%) had dysgranulopoiesis, dyserythropoiesis, and/or dysthrombopoiesis in >10% of granulopoietic cells, erythroid cells, and/or megakaryocytes, respectively. Thirteen dogs had primary myelodysplastic syndromes, and 21 had secondary myelodysplastic syndromes. Of the 13 dogs with primary myelodysplasia, 4 were subclassified as myelodysplastic syndrome with refractory anemia (MDS-RA), and 9 were subclassified as myelodysplastic syndrome with excess blasts (MDS-EB). Secondary conditions associated with dysplasia in the bone marrow included malignant lymphoma (n = 5), myelofibrosis (n = 3), immune-mediated thrombocytopenia (n = 4), immune-mediated hemolytic anemia (n = 5), multiple myeloma with melphalan administration (n = 1), pyometra with estrogen administration (n = 1), polycythemia vera (n = 1), and thrombopathia (n = 1). MDS-RA was characterized by <5% myeloblasts in bone marrow, normal granulocyte maturation ratio, increased erythroid maturation ratio, and dysplastic changes in >15% of erythroid cells. MSD-EB was characterized by >/=5% myeloblasts in bone marrow, high granulocyte maturation and erythroid maturation ratios, >/=32% dysplastic granulocytes, and the presence of small atypical immature myeloid cells. Secondary myelodysplastic syndromes were characterized by <5% myeloblasts in bone marrow, variable granulocyte maturation and erythroid maturation ratios, and variable dysplastic features. These results indicate that morphology alone cannot be used to distinguish primary and secondary myelodysplastic syndromes in dogs.     

Acute myeloid leukaemia (M6B: pure acute erythroid leukaemia) in a Thoroughbred foal

A 10-week-old Thoroughbred filly was referred for anaemia of 4 weeks' duration. Haematology revealed severe anaemia and panleucopenia. Cytological examination of bone marrow smears revealed a myeloid to erythroid ratio <0.02:1 (reference range 0.5-2.4:1.0) and an abundance of erythroid precursor cells. The erythroid cell population included rubriblasts, prorubricytes and rubricytes, with only scant numbers of metarubricytes present. There were numerous mitotic erythroid cells, some of which were atypical and megaloblastic. These cytomorphological changes are consistent with pure acute erythroid leukaemia. No treatment was instituted and the filly died three days after presentation. This case illustrates the need to consider both haematology and bone marrow findings to establish a diagnosis of pure erythroid leukaemia. To our knowledge, there is no documented case of acute myeloproliferative disease in horses involving cells of erythroid lineage, but this condition should be considered a differential diagnosis for horses presenting with anaemia.     

Erythrophagocytic multiple myeloma in a cat

A 7-year-old neutered male domestic shorthair cat was presented to the Veterinary Medical Teaching Hospital at the University of Georgia for further evaluation of a suspected osteolytic lesion of the left 10th rib. Results of a CBC and biochemistry profile revealed mild nonregenerative anemia, hyperproteinemia, hyperglobulinemia, and hypercalcemia. Serum protein electrophoresis was consistent with a monoclonal gammopathy. Marked proteinuria with an increased urine protein to creatinine ratio was found. Cytologic examination of the liver, spleen, and bone marrow revealed numerous plasma cells, many of which were erythrophagocytic. Within the bone marrow, the plasma cells contained phagocytosed metarubricytes in addition to phagocytosed erythrocytes. A diagnosis of erythrophagocytic multiple myeloma was made and treatment with prednisone and melphalan was begun. Four weeks after presentation, the cat was euthanized due to clinical deterioration. A complete necropsy was performed. The distal one-third of the left 10th rib was completely absent. Histologically, there was no evidence for osteolysis or neoplastic cells in the remaining portion of the rib. However, large sheets of plasma cells were found infiltrating the spleen and bone marrow. Moderate erythrophagocytosis by the plasma cells was observed in both organs. The plasma cells, including the erythrophagocytic cells, were positive for CD79alpha by immunohistochemical staining. Erythrophagocytosis by plasma cells as a cause of anemia is uncommon in people with multiple myeloma and is rare in animals. To our knowledge, this is the first report of erythrophagocytic plasma cells in a cat with multiple myeloma.     

Myeloperoxidase-positive acute megakaryoblastic leukemia in a dog

A 16-month-old female spayed Labrador Retriever was referred to the University of Edinburgh for exercise intolerance, inappetence, and severe anemia. A CBC showed severe nonregenerative anemia and moderate numbers of atypical cells with morphologic features most consistent with megakaryoblastic origin. Similar cells were identified in a bone marrow aspirate and accounted for 23% of all nucleated cells. Atypical promegakaryocytes and megakaryocytes were also noted. Myelodysplastic syndrome affecting the megakaryocytic lineage was suspected. Cytologic examination of a fine-needle aspirate of the spleen revealed rare megakaryoblasts similar to those in blood and bone marrow. At necropsy, the bone marrow consisted of atypical megakaryoblasts and megakaryocytes that were also infiltrating spleen, liver, lymph nodes, renal perihilar tissue, and visceral adipose tissue, consistent with acute megakaryoblastic leukemia. Immunohistochemical analysis of splenic sections confirmed megakaryoblastic origin (immunoreactive for CD61 and von Willebrand factor). Some leukemic cells were also immunoreactive for myeloperoxidase (MPO). This aberrant immunophenotype suggested both megakaryocytic and granulocytic/monocytic differentiation of the leukemic cells. To our knowledge, this is the first report of MPO-positive acute megakaryoblastic leukemia in a dog.     

Canine intravascular lymphoma with overt leukemia

A 6-year-old spayed Labrador Retriever Mix dog was evaluated for a 2-week history of progressive generalized weakness and reluctance to stand. Physical examination revealed severe weakness with obtunded mentation, head tilt, bilateral nystagmus, and decreased vision. CBC findings included mild nonregenerative anemia, marked thrombocytopenia, and a few atypical mononuclear cells on the blood film. The cells were 15-30 μm in diameter and had round to oval to reniform centrally placed nuclei with stippled chromatin, prominent nucleoli, and abundant basophilic cytoplasm with numerous discrete vacuoles and, occasionally, small azurophilic granules. Similar cells were found in bone marrow. On histologic examination of tissues collected at necropsy, neoplastic cells were detected in bone marrow, hepatic sinusoids, cerebral and meningeal vessels, and in capillaries of the heart, renal interstitium, small intestinal submucosa, and muscularis, and alveolar septa. A small discrete mass in the right atrium consisted of similar neoplastic cells, and the spleen was diffusely infiltrated. Tissue distribution was suggestive of intravascular lymphoma. Neoplastic cells in tissue sections were immunoreactive for vimentin, CD18, CD45, and granzyme B and lacked immunoreactivity for cytokeratin. Neoplastic cells on bone marrow aspirate smears and blood films lacked immunoreactivity for CD3, CD79a, CD1c, CD11b, CD11c, CD11d, and E-cadherin. In the absence of immunophenotypic evidence for the neoplastic cells being derived from B-cell, T-cell, or histocytic/dendritic lineages and the lack of clonal antigen receptor gene rearrangement(s), along with positive immunoreactivity for granzyme B, a tumor of NK cells was considered likely. Based on current knowledge, this is the first report of canine intravascular lymphoma, of probable NK cell origin, with peripheral blood involvement.     

Thymic lymphosarcoma of T cell lineage in a koala (Phascolarctos cinereus)

Objective To diagnose and characterise thymic lymphosarcoma in a koala.
Design A pathological case.  

Animal

Seven-year-old female koala.
Procedure The neoplastic process was investigated macroscopically, haematologically, histologically and immunohistologically.
Results The koala had difficulty swallowing because of a medial swelling in the lower neck. Biopsy of this mass and blood examination revealed lymphosarcoma with a leukaemic manifestation; necropsy and histopathological examination showed the mass to be thymus. Palatine tonsils, cervical, axillary and mesenteric lymph nodes, spleen, liver, gut, bronchi, genitalia and bone marrow were infiltrated by neoplastic cells. Immunohistological staining of the thymic mass, cervical and mesenteric lymph nodes, bone marrow, spleen and gut revealed the neoplastic cells to be of T lymphocyte origin (positive for both anti-human CD3 and CD5).  

Conclusions

It is speculated that the neoplastic process originated in the thymus and was disseminated by bloodborne neoplastic cells: This first report of thymic lymphosarcoma in a marsupial confirms that antibodies raised originally to investigate human lymphoid neoplasia can cross-react with neoplastic lymphocytes in koalas.     

Pleural fluid from a dog with marked eosinophilia

A 12-year-old neutered male Shar-Pei was presented to the North Carolina State University Veterinary Teaching Hospital cardiology service with a 2-week history of coughing and a 2-day history of lethargy and anorexia. Pleural effusion and a mediastinal mass were detected with thoracic radiographs. Ten mL of fluid were removed via thoracocentesis, and cytologic examination of the fluid revealed marked eosinophilic inflammation and few atypical mast cells. Mast cell neoplasia was suspected. Aspirates of the mediastinal mass, abdominal lymph nodes, and bone marrow contained similar pleomorphic mast cells and increased numbers of eosinophils. The dog was diagnosed with systemic (visceral) mastocytosis, a rare form of neoplasia in dogs, and was euthanized. These tumors carry a poor to grave prognosis and the etiology is uncertain.