Review of diagnostic histologic features of cutaneous round cell neoplasms in dogs.

Cutaneous round cell neoplasms (RCNs) are among the most common skin tumors of dogs. Although a diagnosis can be made in most cases following the examination of H&E-stained routine samples, less-differentiated neoplasms can exhibit overlapping morphologic features that may be challenging to the pathologist, and require immunohistochemistry or molecular testing to reach a final diagnosis. Many patients with cutaneous RCNs are initially seen by a general practitioner and are not referred to a veterinary teaching hospital until a diagnosis has been made. For this reason, anatomic pathology residents at some academic or other training institutions may not be exposed frequently to RCNs during the surgical biopsy service as part of their residency training. In an attempt to fill that gap, here we review the key routine histologic features of canine cutaneous RCNs.

A divergent pseudoglandular configuration of cutaneous plasmacytoma in dogs.

Cutaneous and mucocutaneous plasmacytoma (PCT) is a common neoplasm of dogs. Tumors can be single or multiple and occur predominantly in the oral cavity, lip, ears, digits, and trunk. Although these tumors typically offer no diagnostic challenge for the pathologist, subsets of PCTs with atypical morphologic configurations may make differentiation from other neoplasms difficult. We describe 6 cases of canine cutaneous and mucocutaneous PCT with pseudoglandular arrangement of neoplastic cells. The mean age of affected dogs was 11.3 y, and multiple breeds and sites were affected. Histologically, neoplastic cells were arranged in sheets, packets, and pseudoglandular structures containing central accumulations of blood or eosinophilic material admixed with neoplastic cells and hemosiderin-laden macrophages. Given the presence of pseudoglandular structures resembling neoplastic acini, epithelial neoplasia was occasionally included in the differential diagnosis. Neoplastic cells were strongly immunopositive for multiple myeloma oncogene 1 ( MUM-1) and immunonegative for pancytokeratin AE1/AE3. Canine cutaneous and mucocutaneous PCTs with pseudoglandular morphology may resemble epithelial neoplasia and raise questions about tumor histogenesis.

Immunogenicity of an electron beam inactivated Rhodococcus equi vaccine in neonatal foals.

Rhodococcus equi is an important pathogen of foals that causes severe pneumonia. To date, there is no licensed vaccine effective against R. equi pneumonia of foals. The objectives of our study were to develop an electron beam (eBeam) inactivated vaccine against R. equi and evaluate its immunogenicity. A dose of eBeam irradiation that inactivated replication of R. equi while maintaining outer cell wall integrity was identified. Enteral administration of eBeam inactivated R. equi increased interferon-γ production by peripheral blood mononuclear cells in response to stimulation with virulent R. equi and generated naso-pharyngeal R. equi-specific IgA in newborn foals. Our results indicate that eBeam irradiated R. equi administered enterally produce cell-mediated and upper respiratory mucosal immune responses, in the face of passively transferred maternal antibodies, similar to those produced in response to enteral administration of live organisms (a strategy which previously has been documented to protect foals against intrabronchial infection with virulent R. equi). No evidence of adverse effects was noted among vaccinated foals.

Carboplatin chemotherapy in a cat with a recurrent anal sac apocrine gland adenocarcinoma.

An 8-year-old, castrated male, domestic shorthaired cat was presented for evaluation of a perianal mass. The mass was incompletely excised, and histological assessment resulted in a diagnosis of anal sac adenocarcinoma. The cat had a partial response to carboplatin therapy but a short overall duration of response. Necropsy confirmed the original diagnosis as well as metastasis to the regional lymph nodes and lungs.

Epidemiologia, sinais clínicos e distribuição das lesões encefálicas em bovinos afetados por meningoencefalite por herpesvírus bovino-5 / Epidemiology, clinical signs and distribution of the encephalic lesions in cattle affected by meningoencephalitis caused by bovine herpesvirus-5

São descritos sete surtos e um caso isolado de meningoencefalite por herpesvírus bovino-5 (BoHV-5) em bovinos no Rio Grande do Sul entre 2002 e 2004. Foram afetados bovinos de 1-18 meses, de diversas raças e ambos os sexos. A maior freqüência foi observada em bovinos recém-desmamados e submetidos a outros fatores de estresse. Nesses surtos, de uma população total sob risco de 1.359 bovinos, 54 foram afetados, quatro se recuperaram e 50 morreram espontaneamente ou foram submetidos à eutanásia quando moribundos. Os índices gerais de morbidade, mortalidade e letalidade foram, respectivamente, de 3,97 por cento, 3,67 por cento e 92,59 por cento. A evolução clínica variou de 3-10 dias e os sinais eram caracterizados por depressão, corrimento nasal ou ocular, ranger de dentes, andar em círculos, cegueira, febre, nistagmo, tremores, anorexia, disfagia, sialorréia, incoordenação, pressão da cabeça contra objetos, pêlos arrepiados, taquicardia, taquipnéia, dor abdominal, melena, quedas, decúbito, opistótono, convulsões e movimentos de pedalagem. Dezenove bezerros foram necropsiados. Achados de necropsia foram caracterizados por hiperemia das leptomeninges, tumefação das porções rostrais do telencéfalo, com achatamento das circunvoluções dos lobos frontais; nessas áreas havia focos marrom-amarelados e amolecidos (malacia). Nos casos de evolução clínica mais longa era observada acentuada tumefação, amolecimento e extensas áreas de hemorragia nos lobos frontais telencefálicos. Microscopicamente, todos os bovinos afetados apresentaram meningoencefalite não-supurativa e necrosante, que variou quanto à localização e intensidade nos 19 casos examinados e nas seções de encéfalo de um mesmo caso.

Seven outbreaks and an isolated case of meningoencephalitis caused by bovine herpesvirus-5 (BoHV-5) in cattle in Rio Grande do Sul, Brazil, occurring in 2002-2004, are described. From a total population at risk of 1,359 cattle, 54 1-18-month-old calves from both sexes and several breeds were affected and 50 died spontaneously or were euthanatized while moribund. The highest frequency of cases was in recently weaned calves or calves submitted to other stressing factors. General rates of morbidity, mortality and lethality were respectively 3.97, 3.67 and 92.59. Clinical courses varied from 3-10 days and included depression, nasal and ocular discharge, grinding of teeth, circling, blindness, fever, nistagmus, trembling, anorexia, dysphagia, drooling, incoordination, head pressing, rough hair coat, tachycardia, tachypnea, abdominal pain, melena, falls, recumbency, opisthotonus, convulsions and paddling. Nineteen calves were necropsied. Necropsy findings were characterized by hyperemia of leptomeninges, swollen rostral portions of the telencephalon, and flattening of frontal lobes gyri; frequently in these frontal areas there were segmental brown-yellow discoloration and softening (malacia) of the cortex. In cases with more protracted clinical courses there were extensive swelling, softening and hemorrhaging of the telencephalic frontal lobes. Microscopically, all affected cattle had a necrotizing non-suppurative meningoencephalitis with variable distribution among the 19 cases and among the various telencephalic regions of the same case. The severity of these changes were more marked, in decreasing order of intensity, in the telencephalic frontal cortex, basal ganglia (nuclei), thalamus, brain stem, parietal telencephalic cortex, occipital telencephalic cortex and cerebellum. Perivascular inflammatory infiltrate consisted predominantly of lymphocytes, plasm cells, and less frequently of neutrophils. Additional microscopic findings included variable...

Intoxicação em suínos pela ingestão de sementes de Aeschynomene indica ( Leg. Papilionoideae ) / Poisoning in swine from the ingestion of Aeschynomene indica ( Leg. Papilionoideae ) seeds

Relata-se um surto espontâneo de intoxicação em suínos pela ingestão de sementes de Aeschynomene indica e a reprodução da doença nessa espécie animal. O surto espontâneo ocorreu numa propriedade de criação de suínos localizada na região central do Rio Grande do Sul. Nessa propriedade havia 100 suínos (20 matrizes e 80 suínos jovens de várias categorias). Os suínos eram alimentados com uma ração feita na propriedade pela mistura de 50 por cento farelo de milho, 25 por cento de farelo de soja, 5 por cento de um suplemento vitamínico-mineral de origem comercial e 20 por cento quirera de arroz contaminada por 40 por cento de sementes de A. indica. Embora aparentemente todos os suínos tenham recebido a mesma ração, apenas os suínos de 45 dias de idade foram afetados; as taxas de morbidade, mortalidade e letalidade foram respectivamente 25 por cento-40 por cento, 8,5 por cento-20 por cento e 25 por cento-66 por cento. Os sinais clínicos apareceram cerca de 24 horas após o início da administração da ração contendo sementes de A. indica e incluíam vários graus de incoordenação no andar, quedas, decúbito esternal com membros pélvicos posicionados afastados entre si, decúbito lateral e morte. Não foi possível determinar quantos suínos se recuperaram e quanto tempo levou a recuperação. Um suíno foi submetido à eutanásia e necropsiado na propriedade. A doença foi reproduzida em 5 suínos jovens (A-E) alimentados com uma ração contendo 10 por cento (Suíno A), 15 por cento (Suíno B) e 20 por cento (Suínos C-E) de sementes de A. indica e em um suíno mais velho (Suíno F) que recebeu uma ração com 16,5 por cento de sementes de A. indica. Os sinais clínicos foram semelhantes aos observados nos suínos do surto espontâneo. Os Suínos A, B e F foram submetidos à eutanásia e os Suínos C-E morreram de uma doença aguda respectivamente 16, 21 e 24 horas após o início do experimento. Os achados de necropsia incluíam acentuada hiperemia das leptomeninges em todos os suínos, grandes quantidades de sementes de A. indica no estômago e avermelhamento transmural da parede do intestino e conteúdo intestinal sanguinolento nos Suínos C-E. Um hematoma foi observado no pulmão do Suíno C...

Febre catarral maligna em bovinos no Rio Grande do Sul: epidemiologia, sinais clínicos e patologia / Malignant catarrhal fever in cattle in Rio Grande do Sul, Brazil: epidemiology, clinical signs and pathology

São descritos a epidemiologia, os sinais clínicos e os achados de necropsia e histopatológicos observados em casos de febre catarral maligna (FCM), que ocorreram de 1973 a 2003 em bovinos de 15 fazendas no Rio Grande do Sul. Em nove ocasiões (60 por cento), a doença ocorreu de forma esporádica, afetando 1-3 bovinos por rebanho, enquanto, em seis fazendas (40 por cento), a FCM ocorreu de forma epizoótica, afetando vários bovinos em cada rebanho. As taxas de morbidade variaram de 2,4 por cento a 20 por cento, e as taxas de letalidade foram de 83,3 por cento a 100 por cento. Bovinos de todas as idades e ambos os sexos foram afetados. Nos casos em que foi possível obter essa informação (9 fazendas), sempre havia ovinos em contato com os bovinos afetados, e o maior número de casos de FCM ocorreu na primavera e verão. A doença clínica era aguda ou subaguda, e os sinais clínicos incluíam febre, corrimento nasal e ocular, conjuntivite, salivação excessiva, hematúria, necrose das papilas bucais que se tornavam rombas, linfadenopatia, diarréia e distúrbios neurológicos. Os achados de necropsia incluíam opacidade da córnea, erosões e ulcerações em várias membranas mucosas do trato alimentar, respiratório, urogenital e conjuntiva; aumento de volume e hemorragia em linfonodos e múltiplos focos brancos nos córtices renais e nas tríades portais hepáticas. Dermatite crostosa foi observada em alguns casos. Os principais achados histopatológicos incluíam vasculite, necrose dos epitélios de revestimento e acúmulos de células inflamatórias em vários órgãos. A vasculite era associada com necrose fibrinóide da túnica média das artérias e acompanhada de infiltrado inflamatório constituído por linfoblastos, linfócitos, plasmócitos e macrófagos.

Focal symmetrical encephalomalacia in swine from ingestion of Aeschynomene indica seeds.

A spontaneous outbreak of neurological disease in swine caused by the ingestion of Aeschynomene indica seeds and reproduction of the disease in the same specie are reported. In the natural outbreak the morbidity, mortality and lethality rates were respectively 25%-40%, 8.5%-20%, and 25%-66%. Clinical signs were variable degrees of incoordination of gait, falls, sternal recumbency with wide base stance of the hind limbs, lateral recumbency and death. For experimental reproduction of the intoxication, 5 (A-E) pigs were fed a ration containing 10% (PigA), 15% (Pig B) and 20% (Pigs C-E) of A. indica seeds. Pigs A and B were euthanatized and Pigs C-E died of acute disease respectively 16, 21 and 24 hours after the start of the experiment. Clinical signs were similar to those observed in pigs from the spontaneous outbreak. Histopathological findings in the brain of pigs fed rations with 20% A. indica seeds (C-E) were congestion, edema and hemorrhage and swollen capillary endothelia in nuclei and in the telencephalic cortex. Pigs fed 10% and 15% A. indica had histopathological changes in the brain of discrete focal symmetrical areas of malacia. These findings indicate that one or more toxic principles in A. indica seeds are responsible for this neurological condition and that clinical outcome and pathological changes are dose-dependent. The symmetrical malacic foci from the ingestion of A. indica seeds in pigs affected vestibular and cerebellar nuclei, putamen, and the mesencephalic substantia nigra, oculomotor, and red nucleus; thus, focal symmetrical encephalomalacia is suggested as a better name for the disease.

The pathogenesis of reproductive failure induced in sheep by the ingestion of Ateleia glazioviana.

Seventeen pregnant ewes were orally fed variable amounts of either green or dried leaves of Ateleia glazioviana in 1 through 24 daily doses. All 17 ewes manifested some form of reproductive failure. Nine (52.9%) aborted their fetuses at 4 through 36 d after starting being fed the leaves of the plant; 1 had a stillbirth and in another 1 intrauterine fetal death was diagnosed. The other 6 ewes delivered 8 weak lambs, 7 of which died from few min to 48 h after birth. Three ewes had neurologic disturbances and loss of weight. Thirteen ewes were euthanatized 1-48 h after lambing or pregnancy loss; 2 of them had gross and histopathological changes related to the A glazioviana. Gross and histopathological changes observed in 7 lambs and in a stillborn, and histopathological changes found in 4 aborted fetuses from A glazioviana-fed ewes, were similar to those found in spontaneous poisoning by A glazioviana in adult cattle. It is concluded that A glazioviana has a powerful abortifacient activity whether ingested green or dried. The abortions caused by A glazioviana were not due to placental damage, but rather to transplacental induced fetal lesions consisting of toxic cardiomyopathy and spongy degeneration of the white matter of the brain. Fetuses succumbing to these lesions were expelled from the uterus; those not lethally affected are born weak with meager chances to survive.

Meningoencefalite granulomatosa em bovinos em pastoreio de ervilhaca (Vicia spp) / Granulomatous meningoencephalitis in cattle grazing vetch (Vicia spp)

Meningoencefalite granulomatosa foi observada em 7 de 8 vacas leiteiras adultas afetadas por doença granulomatosa sistêmica associada ao consumo de ervilhaca, embora nenhum dos bovinos afetados apresentasse sinais de distúrbios nervosos. Os infiltrados inflamatórios localizavam-se nas leptomeninges e como manguitos perivasculares no interior do encéfalo; consistiam de macrófagos epitelióides, linfócitos, plasmócitos e eosinófilos. Essas alterações inflamatórias variavam de leves a acentuadas de animal para animal e entre diferentes regiões do encéfalo de um mesmo animal. Geralmente, os manguitos perivasculares eram mais acentuados que os infiltrados nas leptomeninges. As regiões do encéfalo afetadas, em ordem decrescente de intensidade, diencéfalo através da massa intermedia; mesencéfalo na altura dos colículos rostrais; ponte e pedúnculos cerebelares, bulbo na altura do óbex, lobo frontal na altura do joelho do corpo caloso e cerebelo. O tipo e a distribuição das alterações inflamatórias são enfatizados em relação ao diagnóstico diferencial de outras doenças e lesões do sistema nervoso central de bovinos no contexto do programa brasileiro de vigilância para a encefalopatia espongiforme bovina.

Poisoning in sheep from the ingestion of fruits of Erythroxylum argentinum.

Epidemiological, clinical and pathological aspects of an unreported plant poisoning are described in sheep from southern Brazil. The disease occurred during the summer of 2003/2004 in 173 crossbred sheep with morbidity, mortality and lethality rates respectively of 31.8%, 8.1%, and 25.5%. Affected sheep were reluctant to move; when forced to walk they had stiff uncoordinated gaits, dragged their toes and bumped into objects in their path. When standing they assumed a wide base position with the legs widely spread apart. Increased respiratory rates, laborious breathing and cyanosis were marked in affected sheep that died. The experimental feeding of 2 sheep with the fruits of Eythroxylum argentinum reproduced the clinical disease. Except for consistent findings of distended bladder and the presence of E. argentinum undigested seeds in the abomasum and rumen in 4 necropsied sheep, no significant necropsy and histopathological findings were found. It was concluded that the ingestion of fruits of E. argentinum was the cause of this disease in sheep.