Pulmonary aspergillosis in a horse with myelomonocytic leukemia

Acute myelomonocytic leukemia was diagnosed in a 2-year-old Standardbred mare that had hind limb edema and fever unresponsive to antibiotics. The mare had anemia, thrombocytopenia, and leukocytosis, with circulating myeloblasts and monocytoid cells. A bone marrow specimen was hypercellular, with myeloblasts and monocytoid cells. Peroxidase, chloroacetate esterase, and alpha naphthyl acetate esterase activities were detected in many bone marrow cells. Interstitial pulmonary densities were seen radiographically. The mare was euthanatized and necropsied. Infiltrates of leukemic cells were found microscopically in specimens of spleen, lymph nodes, liver, kidneys, gastrointestinal tract, and lungs. Granulomas containing fungal hyphae were seen microscopically in the lungs, and Aspergillus sp was isolated from the lesions.     

Pathology of the mononuclear cell leukemia of Fischer rats. I. Morphologic studies

Pathological evaluations were done in 205 rats with mononuclear cell leukemia. Leukemia was diagnosed in 22.2% of males and 20.4% of females with significant risk beginning at 20 months of age. Mononuclear cell leukemia was responsible for 50% of early deaths in two-year studies. Clinically, rats became depressed, pale, icteric and had palpably enlarged spleens. Gross lesions included splenomegaly, enlarged mesenteric lymph nodes, and mottled livers. Hemorrhages occurred in the lungs, brain, and lymph nodes. Histological examination demonstrated that spleen and liver were most consistently and seriously involved, although numerous other organs contained leukemic infiltrates of variable severity. Spleens exhibited diffuse leukemic infiltration of the red pulp, follicular lymphoid depletion, and decrease in both extramedullary hematopoiesis and hemosiderin. Liver lesions consisted of diffuse centrilobular degeneration and necrosis. Erythrophagocytosis by tumor cells was common in the spleen and observed in liver, lymph nodes, and adrenals. The disease appeared to originate in the spleen. Bone marrow infiltration occurred late relative to spleen involvement and was present in less than half of the rats.     

B-cell leukemia in a sheep

Necropsy examination was performed on an 8.5-year-old Finnish ewe euthanatized because of progressive respiratory distress, cachexia, and weakness. Significant postmortem findings included a diffusely enlarged, dark-red friable liver, mild splenomegaly, and mild mesenteric lymphadenopathy. Examination of multiple tissue sections revealed intravascular atypical mononuclear cells in all tissues examined, with a leukemic pattern of infiltration of mesenteric lymph nodes, liver, lung, and spleen. Neoplastic cells were positive for CD79a and negative for CD-3, BLA.36, and CD68 leukocytic markers. The final diagnosis was B-cell leukemia.     

A clinical case of acute myelomonocytic leukemia in a Holstein cow

A 2-year, 3-month-old Holstein cow presented with anorexia and enlarged superficial lymph nodes. Fine needle aspiration cytology of the superficial lymph nodes revealed large blast cells. Hematological examination revealed anemia, neutropenia, and blast cells in peripheral blood. Blast cells were the predominant cell type in bone marrow aspirates. Of the non-erythroid cells, 26%, 58%, and 18% were positive for myeloperoxidase, α-naphthyl acetate esterase, and naphthol AS-D chloroacetate esterase, respectively. Pathological examination revealed the proliferation of neoplastic cells, which were positive for monocytic markers, in the affected lymph nodes. The cow was diagnosed with acute myelomonocytic leukemia based on these findings. This report highlights the importance of performing bone marrow aspiration cytology and cytochemical staining when diagnosing bovine myeloid leukemia.     

Pathological findings of two types of lymphoid malignancy in sheep inoculated with bovine leukemia virus

Different types of lymphoid malignancy were observed in two sheep inoculated with BLV-containing materials. Sheep 1 showed severe leukemic change in the peripheral blood and splenomegaly but lymphosarcoma in the lymph nodes was absent. Sheep 2 had lymphosarcoma in the lymph nodes and various organs. Neoplastic cells had B-cell marker in both cases and a few neoplastic cells contained intracytoplasmic IgM in sheep 2. It was presumed that B-cells might be transformed into neoplastic cells on the way of their differentiation. Some of neoplastic cells might have ability of immunoglobulin-production in sheep 2.     

Effects of large granular lymphocyte leukemia on bone in F344 rats

Large granular lymphocyte (LGL) leukemia was induced in 40 F344 rats by inoculating them with neoplastic cells to evaluate the effect of acute leukemia on bone remodeling and calcium balance. The rats developed leukemia and splenomegaly by 9 days after inoculation. The rats had reduced body weight (day 12), food intake (days 4, 8, 12), urine production (day 12), and fecal output (day 12). Serum calcium and phosphorus and urinary excretion of calcium and phosphorus were decreased on days 8 and 12 in leukemic rats. Static bone histomorphometry of trabecular bone in lumbar vertebrae demonstrated reduced bone area, no change in the number of osteoclasts, and reduced osteoclast perimeter at day 12. Dynamic bone histomorphometry revealed reduced double labeled perimeter, mineralizing perimeter, trabecular mineral appositional rate, and bone formation rate in rats with LGL leukemia at days 9 and 12. There was no change in periosteal mineral appositional rate. Rats with leukemia and intramedullary neoplastic cells had a reduction in bone formation rate that resulted in a loss of trabecular bone.     

Chronic eosinophilic leukemia in a cat: cytochemical and immunophenotypical features

A 3-year-old, male, domestic shorthaired cat was presented with a 3-day history of anorexia and depression. The cat was moderately dehydrated, had pale, slightly icteric, mucous membranes, oral ulcerations, and mild hepatosplenomegaly. A feline leukemia virus (FeLV) antigen test was positive. CBC results obtained at initial presentation included severe normocytic, normochromic, nonregenerative anemia, severe thrombocytopenia, and marked leukocytosis (>100,000/microL) with 77% eosinophils. After 15 days of treatment with prednisone and doxycycline, the cat had persistent severe nonregenerative anemia (HCT 3.4%), thrombocytopenia (28,000/microL), and extreme eosinophilia (total eosinophils, 123.1 x 10(3)/microL; segmented 103.0 x 10(3)/microL; immature 20.1 X 10(3)/microL). Cytologic examination of aspirates from bone marrow, liver, lymph nodes, and spleen revealed a predominance of mature and immature eosinophils, many with dysplastic changes. The M:E ratio was 96.4. On histopathologic examination, multiple organs were infiltrated by eosinophilic granulocytes. Neoplastic cells in blood and bone marrow stained positive for alkaline phosphatase and were negative for myeloperoxidase, chloroacetate esterase, and alpha-naphthyl acetate esterase. On flow cytometric analysis of peripheral blood, the neoplastic cells were positive for CD11b and CD14. These findings were consistent with chronic eosinophilic leukemia. To our knowledge, this is the first report of chronic eosinophilic leukemia in a cat associated with naturally acquired FeLV infection, in which flow cytometry was used to characterize the neoplastic cells.     

Thrombocytosis and central nervous system involvement in a case of canine acute megakaryoblastic leukemia

This case report presents a 14‐month‐old female Poodle mix with acute megakaryoblastic leukemia based on a marked thrombocytosis, abnormal platelet morphology, circulating dwarf megakaryocytes, and blast cells in the blood. Bone marrow abnormalities included dysmegakaryopoiesis dygranulopoiesis, and an increased number of blast cells was observed in the blood. Extensive leukemic involvement was also found in the liver, spleen, lymph nodes, lungs, kidneys, and brain. The cytopathologic features of the abnormal circulating cells were highly suggestive of being megakaryocytic in origin, which was supported by negative myeloperoxidase staining and positive von Willebrand factor staining on immunocytochemistry (ICC). The neoplastic cells were also CD61 positive and had variable von Willebrand factor expression on ICC. Although there were only 25% blast cells in the bone marrow, which theoretically supported myelodysplastic syndrome, the hypothesis that this case represented acute myeloid leukemia of megakaryoblastic origin was confirmed by the continuous increase in circulating blast cell numbers during follow‐up visits and the extensive leukemic involvement of parenchymal organs.     

Ultrastructural morphology of leukemic cells in the cat

Transmission and scanning electron microscopic characteristics of leukemic cells from eight cats with spontaneous leukemia are described. Nuclear blebs, myelin figures, cytoplasmic microfibrils and C-type virus were seen more frequently in leukemic cells. Surface ridges and ruffles seen with the scanning electron microscopy were helpful in distinguishing myelogenous from lymphogenous leukemia.     

Acute myeloid leukemia with mastocytic and megakaryocytic differentiation in a calf

A diagnosis of acute myeloid leukemia was made in a 10-month-old Holstein female calf. The leukemia was macroscopically characterized by great enlargement of the spleen and moderate enlargement of some lymph nodes. Histochemical and immunohistochemical examination disclosed the presence of neoplastic cells either containing metachromatic and tryptase-positive granules or expressing factor VIII-related antigen. The granules, which were positive for naphthol AS-D chloroacetate esterase and did not have particulate contents, were distinct from those of basophilic leukemia cells. This leukemia was thought to be derived from a common myeloid progenitor capable of giving rise to megakaryocyte-erythrocyte progenitors and granulocyte-monocyte progenitors with the ability to differentiate into mast cells.     

Disseminated histiocytic sarcoma with peripheral blood involvement in a Bernese Mountain dog

Abstract: A 6‐year‐old Bernese Mountain dog was presented with a history of lethargy and weight loss of 2 weeks duration. On physical examination the dog had pale mucous membranes and tachypnea. Ultrasound examination revealed hepatomegaly, splenomegaly, and mesenteric lymphadenomegaly. Results of a CBC included marked normocytic normochromic nonregenerative anemia, marked thrombocytopenia, and moderate leukocytosis with mild neutrophilia and a large population of unclassified round cells (6.2 × 10³/μL). The unclassified cells occasionally were bi‐ or multinucleated and had variably abundant pale basophilic cytoplasm that contained multiple irregular clear vacuoles and occasionally erythrocytes. Fine needle aspirate specimens of the mesenteric lymph nodes and spleen were composed of a population of round pleomorphic cells with the same features as the circulating cells. On flow cytometric analysis of peripheral blood, the unclassified cells expressed CD18, CD45, CD11c, CD1c, and CD14; immunocytochemical analysis of blood smears also indicated the cells were positive for CD1c, CD1a, and CD11c. The dog died a few hours after referral. The histologic interpretation of samples collected from spleen, liver, and lymph nodes was malignant neoplasia of histiocytic origin. Immunohistochemical staining yielded negative results for CD11d, a marker of red‐pulp macrophages, ruling out hemophagocytic histiocytic sarcoma. Based on clinical and pathologic findings, the final diagnosis was disseminated histiocytic sarcoma (DHS) with peripheral blood involvement. To our knowledge, DHS in a dog with evidence and immunophenotyping of neoplastic cells in peripheral blood has been reported only rarely.     

The use of cytochemistry,immunophenotyping, flow cytometry,and in vitro differentiation to determine the ontogeny of a canine monoblastic leukemia

We evaluated the utility of cytochemistry, immunophenotyping, flow cytometry, and in vitro culture with forced differentiation of leukemic cells as diagnostic aids to identify the malignant cell ontogeny in a dog with leukemia. A tentative diagnosis of monoblastic leukemia was established by microscopic examination of Romanowsky-stained blood smears and bone marrow aspirate smears. This diagnosis also was supported by the light scatter signature that identified the blast cells as large, non-granular monocytic cells using a CellDyn 3500 automated hematology analyzer; as well as by the detection of N-butyrate esterase and the lack of choloroacetate esterase or leukocyte peroxidase by cytochemical staining. Subsequently, leukemic cells were isolated from the dog's peripheral blood and placed into tissue culture or cryopreserved. The leukemic cells grew in suspension cultures and proliferated spontaneously for up to 4 days. By day 7, proliferation was negligible. Upon culture with conditioned supernatant using mitogen-stimulated human T cells as a source of cytokines, an increased proportion of cells entered S phase by day 2 of culture; however, proliferation declined markedly by day 4, at which time the cells had apparently differentiated to adherent, vacuolated macrophages. The cytokine-stimulated leukemic cells were positive for the monocyte/macrophage specific markers alpha-1-antitrypsin, alpha-1-antichymotrypsin, lysozyme, CD14, MHC class II, and calprotectin, an antigen found in differentiated macrophages and granulocytes. Despite the strong tendency of the leukemic cells towards monocytic differentiation, our results suggested that they retained some features of a myelomonocytic precursor. These data show that cytochemistry, immunophenotyping, flow cytometry, and in vitro differentiation of canine leukemia cells are useful tools for confirming the lineage of malignant hematopoietic cells.     

家蚕蛾溶茧酶分泌器官及蛾吐出液的研究

家蚕蛾溶茧酶可能来源于下颚、嗉囊和中肠,嗉囊是否具有分泌溶茧酶的能力至今缺乏直接的证据。分别用光学显微镜和透射电镜观察了家蚕蛾下颚、嗉囊和中肠的组织结构,发现嗉囊不具备分泌器官的形态特征,是由薄的膜围成的囊状结构,没有观察到分泌细胞及其分泌物;而下颚和中肠具有分泌细胞,存在大量的分泌物质。对蛾吐出液进行酶活性检测,发现蛾吐出液除具有酯酶活力外,还具有纤溶酶活力。分别对下颚、嗉囊和中肠的组织蛋白作酯酶活力和纤溶酶活力测定,发现嗉囊组织蛋白不具有这两种酶活力,而下颚和中肠的组织蛋白具有较强的酯酶和纤溶酶活力。以上实验结果表明:家蚕蛾溶茧酶的来源不是嗉囊,溶茧酶可能来源于下颚和中肠。     

Lymphosarcoma development in sheep experimentally infected with bovine leukaemia virus

Twelve sheep were experimentally infected with a phytohemagglutinin (PHA) treated short term culture of lymphocytes from a cow naturally infected with BLV at the PL stage. Five of 12 (42%) BLV infected sheep had histologically confirmed lymphosarcoma 10-16 months after infection. The PBL's were increased to leukemic levels 3-21 weeks before death due to lymphoblastic leukemia. Lymphocyte proliferation and appearance of immature lymphocytes and lymphoblastic cells in the blood were a characteristic feature of tumour development following inoculation with an Australian strain of BLV. In contrast to a number of previous studies the peripheral lymph nodes of all infected sheep were clinically normal throughout the experimental period but at death gross tumours were evident in the mesentric lymph nodes and the heart in all cases. All the other lymph nodes, liver, spleen, kidney and lung were histologically infiltrated with lymphoid tumour cells. Gross tumours were present in the abomasum (1 out of 5) in the urinary tract (2 out of 5) and in the uterus (1 out of 2). The majority of the tumour cells isolated from the various tissues were centroblastic demonstrating that the malignant leukemia in experimentally infected sheep was of a multicentric centroblastic type. The central nervous system was not involved in any case.     

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.     

Ultrastructural morphology of leukemic cells from 14 dogs

Transmission and/or scanning electron microscopic features of leukemic cells from seven dogs with myelomonocytic leukemia, four dogs with monocytic leukemia, and three dogs with lymphocytic leukemia were studied. Few ultrastructural features distinguished normal cells from leukemic cells. Nuclear to cytoplasmic asynchrony, abnormal cytoplasmic granules, nuclear pockets, and cytoplasmic fibrillar bundles were seen more frequently in leukemic cells. Small ridges or ruffles and a few microvilli were surface characteristics of cells from dogs with myelomonocytic leukemia. An occasional cell had large undulating ruffles. Cells from dogs with monocytic leukemia and lymphocytic leukemia usually had smoother surfaces.     

Acute megakaryoblastic leukemia with erythrophagocytosis and thrombosis in a dog

A 7-year-old, intact male Dachshund was presented to the Lyon veterinary school for lethargy and anorexia of several weeks duration. The main clinical signs were pale and icteric mucous membranes, hepatomegaly, splenomegaly, and lymphadenopathy. Results of a CBC and plasma biochemistry tests revealed severe nonregenerative anemia, thrombocytopenia, and increased alanine aminotransferase and alkaline phosphatase activities. Blood smear evaluation and cytologic examination of lymph node and bone marrow aspirate specimens revealed a large population of poorly differentiated blast cells with morphologic features suggesting megakaryocytic lineage. A low number of well-differentiated but dysplastic megakaryocytes also were observed in lymph node and bone marrow smears. A few blast cells were erythrophagocytic. Blast cells were positive for glycoprotein IIIa, factor VIII-related antigen, and factor XIII using immunocytochemistry. The dog was euthanized and necropsied. Histologic findings consisted of diffuse, massive infiltration of lymph nodes, liver, and spleen by megakaryoblasts and atypical megakaryocytes, with widespread thrombosis. This case confirms the usefulness of immunochemistry, including for factor XIII, in the diagnosis of megakaryoblastic leukemia, and demonstrates the unique features of tumor cell erythrophagocytosis and marked fibrinous thrombosis, which have not been reported previously in dogs.     

Histopathology and distribution of cells harboring bovine leukemia virus (BLV) proviral sequences in ovine lymphosarcoma induced by BLV inoculation.

Six sheep with lymphosarcoma induced by hypodermic inoculation of bovine leukemia virus (BLV) materials were examined to elucidate the relation between pathologic lesions and integration of BLV provirus in cellular DNAs. Antibodies to BLV gp-antigens had been detected since the 3rd week after the inoculation, and BLV was positive when checked 3 months later. Lymphosarcomas followed the leukemic phase in 4 sheep. The other 2 sheep showed initial lesions of lymphosarcoma and were aleukemic clinically. Five animals were killed by enthanasia and autopsied at 2.5 to 3.5 years postinoculation (pi) because of their diseased condition. One animal died 10 years pi following the 4th leukemic episode. Sarcomatous lesions were confirmed grossly and histologically, and the proliferating neoplastic cells were classified into lymphocytic, prolymphocytic, lymphoblastic and histiocytic types. Integration of BLV provirus in cellular DNAs of the peripheral blood lymphocytes (PBL) and neoplastic cells of sarcomatous lesions was examined by Southern blotting technique. BLV provirus was demonstrated in the PBL of all infected animals and in most of the sarcomatous lesions of the spleen, kidney and lymph nodes except 4 lymph nodes showing slight neoplastic infiltration. The results indicated that ovine lymphosarcoma could be caused by BLV and the cells carrying proviral information seemed to be disseminated and proliferate in the lesions.     

Hypereosinophilic syndrome in cats: a report of three cases.

The clinical, clinicopathological and pathological findings in three cats with hypereosinophilic syndrome are described. The cats chosen for the study had marked eosinophilia and evidence of tissue infiltration by eosinophils. Necropsies were performed on two cats, biopsy and blood samples were provided for the third cat. At necropsy, there was diffuse reddening of femoral bone marrow with ulceration and thickening of the duodenum. The livers had an enhanced lobular pattern with multiple, white, 1-3 mm nodules throughout the parenchyma. One cat had splenomegaly and the other had several enlarged, white, firm lymph nodes. Histopathologically, there was eosinophil infiltration of intestine, lymph nodes, liver, spleen, adrenal medulla and beneath the endocardium. Ultrastructurally, the eosinophils from lymph node and bone marrow of cat II were morphologically normal. The rigid criteria for eosinophilic leukemia were not fulfilled by these cases and the etiology of the eosinophilia in each case is not known. Possible pathogenic mechanisms are discussed.     

Leukemic small cell lymphoma or chronic lymphocytic leukemia in a horse

A 16‐year‐old, Irish Draft mare was admitted to the referring veterinarian for an annual health check. A mild generalized lymphadenomegaly was noted. Rectal palpation and transrectal ultrasonographic examination revealed prominent mesenteric lymph nodes. A transcutaneous abdominal ultrasonographic evaluation was unremarkable. A CBC revealed a marked leukocytosis (63.06 × 10³/μL) and lymphocytosis (58.2 × 10³/μL) due to increased numbers of small lymphocytes. No evidence of anemia or thrombocytopenia was found and neutrophil counts were low‐normal. Cytologic examination of fine‐needle aspirates of multiple lymph nodes and a bone‐marrow aspirate revealed the presence of a monomorphic population of small lymphocytes similar to those observed in the peripheral blood, suggesting a leukemic small cell lymphoma (SCL) or chronic lymphocytic leukemia (CLL). As the lymphadenomegaly and peripheral blood lymphocytosis were present simultaneously, the distinction between these 2 conditions was not possible. Immunophenotyping by immunocytochemistry and flow cytometry of the lymphoid cells in peripheral blood determined a T‐cell phenotype. As the horse was clinically stable, no treatment was initiated, but regular examinations were undertaken. A CBC repeated 120 days after the diagnosis showed a marked lymphocytosis (157.6 × 10³/μL) with no evidence of anemia or other cytopenias. The horse was euthanized 194 days after the initial diagnosis. Histopathology and immunohistochemistry of submandibular lymph nodes and bone marrow confirmed the diagnosis of leukemic SCL or CLL, and a T‐cell phenotype. SCL and CLL are rare in horses; previous immunohistochemical studies determined that the T‐cell phenotype is predominant. To the authors' knowledge, this is the first report of the combined use of immunocytochemistry and flow cytometry in a horse with leukemic SCL or CLL.