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.     

Chronic eosinophilic keratitis in the cat

A special form of keratitis in the cat is described on the basis of 8 clinical cases. The disease has been known in the United States and the United Kingdom for some time, however, it has, to our knowledge, never been described in Switzerland. This keratitis is characterized by chronicity and infiltration of the cornea by mast cells and eosinophils. It is usually an unilateral and painless condition. We describe the clinical features and diagnostic examinations of the disease. Cytology of a corneal scraping is usually diagnostic. As in the cases described in the literature the cats were successfully treated with oral megestrol acetate. The aetiology of the disease is unknown.     

Idiopathic localized eosinophilic synovitis in a cat

Abstract: A 4-year-old male castrated Seal Point Himalayan cat was presented for evaluation of right thoracic limb lameness of 6 weeks duration. Synovial fluid analysis of the swollen right carpal joint revealed a mixed cell synovitis, with a total nucleated cell count of 13,200/μL and 34% eosinophils. A diagnosis of idiopathic localized eosinophilic arthritis was made. Additional clinical and diagnostic findings included mild lym-phadenopathy with lymphoid hyperplasia and an antinuclear antibody titer of 1:320. Lack of multisystem involvement made systemic lupus erythematosis unlikely. Immunosuppressive therapy with oral prednisone alleviated the lameness. Eosinophilic synovitis has not previously been reported in cats. An immune-mediated mechanism was likely in this case; however, the exact etiology remains unknown.     

Chronic myelomonocytic leukemia in a cat

A 1-year-old spayed domestic short-haired cat was referred with anorexia and weight loss. Hematologic findings indicated nonregenerative anemia, severe neutropenia and monocytosis. The feline leukemia virus (FeLV) antigen test was positive reaction by enzyme-linked immunosorbent assay. Dysgranulopoiesis with slight increase in blast cells were observed in bone marrow smears. On the basis of blood and bone marrow findings, the cat was diagnosed as chronic myelomonocytic leukemia (CMMoL), which possibly corresponds to a kind of the subtypes in human myelodysplastic syndrome (MDS).     

Cryptosporidiosis in a feline leukemia virus-positive cat

A 4-year-old FeLV-positive cat with a 1-year history of intermittent diarrhea and subsequent anorexia, depression, and weight loss had enteric cryptosporidiosis at necropsy. Cryptosporidium sp is an important cause of gastroenteritis and diarrhea in various species, including human beings with acquired immunodeficiency syndrome. A major determinant of the severity of the disease caused by Cryptosporidium sp is the immunologic status of the affected animal. Cryptosporidiosis should be included in the differential diagnosis of protracted diarrhea in FeLV-positive cats. Because cryptosporidiosis now is recognized as a zoonosis, cats with this disease should be considered a potential source of human infection.     

Eosinophilia in a cat with acute leukemia

A 4-year-old castrated male domestic shorthaired cat with a history of vomiting and anorexia was diagnosed with leukemia with marked hepatic and splenic infiltration and concurrent eosinophilia with marked tissue infiltration. Despite thorough immunocytochemical and immunohistochemical immunophenotyping, the cell lineage of the leukemia was not identified.     

Acute monoblastic leukemia in a FeLV-positive cat

A 1.6-year-old male domestic short hair cat was brought to the Veterinary Medical Teaching Hospital, Kasetsart University, with signs of severe anemia, depression, and general lymph node enlargement. Complete blood count revealed leukocytosis and massive undifferentiated blasts. Testing for antibodies specific to feline leukemia virus (FeLV) was positive, and FeLV nucleic acid was confirmed by nested polymerase chain reaction. Base on cytochemistry and ultrastructure, the cat was diagnosed with acute monoblastic leukemia.     

Myelodysplastic changes in a cat with myelomonocytic leukemia

Submandibular and/or disseminated zygomycosis (mucormycosis) was diagnosed in 3 feeder pigs from 2 farrow-to-finish farms. Affected pigs were stunted and unthrifty. Each pig had a large unilateral submandibular granuloma replacing the mandibular lymph node on the affected side. Two pigs had disseminated lesions. One had an abscess on the serosa of the stomach; another had abscesses scattered throughout the liver and mesenteric lymph nodes. Impression smears were made of several masses and stained with blue-black ink. Examination of smears by light microscopy revealed coarse, infrequently septate, irregularly branching, mucoraceous fungi typical of a Zygomycete. Histologic examination of the submandibular masses revealed granulomas containing large numbers of mixed inflammatory cells, including giant cells. Mesenteric lymph nodes and liver abscesses had necrotic cores surrounded by fibrous capsules infiltrated by mixed inflammatory cells. Hyphae of a mucoraceous fungus were scattered throughout all masses. The 2 pigs submitted alive had marked serum hypoproteinemia, including hypoglobulinemia.     

Acute erythroid leukemia with multilineage dysplasia in a cat

Dysplastic features of erythroid and megakaryocytic lineages were observed in a cat with acute erythroid leukemia. We demonstrated that flow cytometry analysis of the expression of glycophorin A and CD71 by neoplastic cells can be helpful in the diagnosis of this type of feline leukemia.     

Visceral mast cell tumour with eosinophilia and eosinophilic peritoneal and pleural effusions in a cat

Summary A cat with weight loss, pyrexia and recurrent lethargy and depression was found to have pleural and peritoneal eosinophilic effusions, peripheral eosinophilia, eosinophilic lymphadenitis and a massively enlarged mesenteric lymph node. Visceral mast cell neoplasia was diagnosed after histopathological examination of a biopsy of the mass. Palliative chemotherapy was attempted unsuccessfully and the cat was euthanased.     

Low-dose cytosine arabinoside-induced remission of lymphoblastic leukemia in a cat

Low-dose cytosine arabinoside (10 mg/m2, q 12 h), an antimetabolite chemotherapeutic agent, was administered subcutaneously to a cat with aleukemic lymphoblastic leukemia. After several weeks of this treatment, there was marked improvement in the neutrophil count and PCV, as well as restoration of adequate numbers of normal bone marrow cells. The remission lasted 10 weeks.