Primary third eyelid lymphoma with aggressive local behavior in a dog.

Lymphoma is the most common hematopoietic neoplasm in dogs. However, cases primarily involving the third eyelid are rarely reported in the species. The subtype most frequently described in this location is marginal zone lymphoma of the mucosa-associated lymphoid tissue, which has an indolent behavior. A 10-year-old intact female Poodle was presented with a 2-month history of a nodule in the left third eyelid for evaluation. This nodule was surgically excised; however, local recurrence was detected nineteen days postoperatively, with the formation of a mass that expanded and replaced the extraocular orbital tissues and infiltrated the eye. Euthanasia was elected due to the deteriorating clinical condition, and a necropsy was performed. Macroscopically, the mass infiltrated and expanded the eyelids with narrowing of the palpebral fissure, expanded into the orbital space, and infiltrated the cornea and bulbar conjunctiva. Histologically, the mass was composed of sheets of intermediate to large neoplastic lymphocytes, with frequent epitheliotropism and tingible bodies. Neoplastic lymphocytes were immunoreactive for PAX5, CD20, and CD79a and were not immunoreactive for CD3. The neoplasm was restricted to the left eyelid and orbit. A diagnosis of primary third eyelid lymphoma (extranodal) with immunophenotype B and locally aggressive behavior was made based on the macroscopic, histological, and immunohistochemical findings.

Pathological findings and patterns of feline infectious peritonitis in the respiratory tract of cats.

Feline infectious peritonitis (FIP) is an important cause of death in cats. Thoracic manifestations are less common than abdominal manifestations, and FIP-associated respiratory disease is poorly documented. This study aimed to investigate pathological findings in the respiratory tract of cats with FIP and the occurrence and distribution of feline coronavirus antigen in the respiratory tract using immunohistochemistry. A retrospective study was carried out on 112 cats with FIP, of which 66 had inflammatory histological lesions in the respiratory tract (58.9%) and were included in this study. Three major gross patterns were defined: marked fibrin deposition in the thoracic cavity with lung atelectasis; marked fibrin deposition in the thoracic cavity with lung pyogranulomas; and lung pyogranulomas without thoracic effusion. Histological analysis revealed primary lesions in the visceral pleura and lung parenchyma at a similar frequency, with multifocal to diffuse presentations. Marked lesions were commonly observed. Five major histological patterns were defined: pleuritis; pleuritis and vasculitis/perivascular injury in the lung parenchyma; pleuritis and pneumonia; perivascular injury in the parenchyma without pleuritis; and pneumonia without pleuritis. In the pleura and pulmonary parenchyma, FIP virus antigen was detected in perivascular and peribronchial macrophages and in macrophages within bronchial-associated lymphoid tissue and foci of necrosis and inflammation in the pleura and lung parenchyma. Co-infections with retroviruses were detected in 47 cats (71.2%), mainly with feline leukemia virus (62.2%). Although FIP is a systemic disease, some cats developed significant lesions in the thoracic cavity, including involvement of the upper respiratory tract and presenting respiratory signs, without other classic signs of FIP. This work advances our knowledge of FIP in the respiratory system, helping veterinarians to recognize the various presentations of this disease.

Auricular and laryngeal chondritis in nursery and finishing pigs.

This work aimed to characterize the clinic-pathological presentation of an outbreak of auricular and laryngeal chondritis in pigs. Visits were made to pig farms, where the clinical history was obtained, and clinical and postmortem examinations were performed. In those farms, 3% to 4% of pigs presented otohematomas, which started in the nursery and extended to the finishing phase. Moreover, some finishing pigs presented with respiratory distress, initially characterized as inspiratory dyspnea, associated by an uncommon respiratory stridor and culminating in death. Grossly, nursery piglets had enlarged ears, and on the cut surface, the cartilage was fragmented and associated with blood clots. In the finishing phase, in addition to auricular lesions, the epiglottis and arytenoid cartilages were thickened and distorted, which partially occluded the lumen. Microscopically, the laryngeal and auricular cartilages were fragmented, displayed a loss of matrix basophilia, and were surrounded by lymphohistiocytic inflammatory infiltrate, with occasional multinucleated giant cells and fibrosis. The lesions exclusively affected elastic cartilages. The disease in finishing pigs led to increased mortality and was a differential diagnosis to respiratory challenges. It was not possible to determine the factor that triggered this condition; however, a nutritional association is suspected. To the authors' knowledge, this is the first report of primary auricular and laryngeal chondritis in pigs.

Encephalic meningioangiomatosis in a dog with high-grade undefined glioma.

Meningioangiomatosis (MA) is a rare proliferative meningovascular disorder that affects mainly the cerebral cortex, brainstem and spinal cord of humans and animals and can coexist with other proliferative disorders. A 7.5-year-old male Brazilian Campeiro Bulldog died after a convulsive crisis and cardiorespiratory arrest. At necropsy, a firm, white mass involving the piriform and right occipital lobes was seen. Histologically, the mass consisted of two morphologically distinct entities that collided: a congenital malformation characterized by a proliferation of meningothelial cells around blood vessels, within the perivascular spaces; and a neoplasm composed of two cell populations with astrocytic and oligodendrocytic differentiation. Meningothelial cells and neoplastic glial cells immunolabelled for vimentin. This first reported case of encephalic MA with a high-grade undefined glioma in a dog was confirmed through clinical signs, pathological and immunohistochemical findings.

Undifferentiated pleomorphic sarcoma in a white-eared opossum (Didelphisalbiventris).

We report a case of high-grade undifferentiated pleomorphic sarcoma in a free-living white-eared opossum (Didelphis albiventris) in Central Brazil. Grossly, it appeared as a soft yellow mass, approximately 8 cm in diameter, with an irregular, adherent and ulcerated surface, which extended from the proximal epiphysis of the femur to the proximal third of the tibia and fibula. The mass invaded the medullary cavity and had a necrotic centre. Multiple nodular metastases (0.5-1.5 cm) were present in the liver, lungs and spleen. Histologically, the neoplasm was characterized by pleomorphic cells with indistinct boundaries, many multinucleated cells, necrosis and tissue invasion. There was intense cytoplasmic immunolabelling of neoplastic cells for vimentin and moderate cytoplasmic and nuclear labelling for human muscle actin, human smooth muscle actin and lysozyme. Immunolabelling for Iba1, CD18, CD1A, cytokeratin AE1/AE3, glial fibrillary acidic protein and desmin was negative. To our knowledge, this is the first report of an undifferentiated pleomorphic sarcoma in this species.

Glioma with cribriform plate involvement in 6 dogs.

Distinct patterns of local infiltration are a common feature of canine oligodendroglioma and astrocytoma, and typically involve the surrounding neuroparenchyma, ventricles, or leptomeninges. Infiltration of adjacent extraneural sites is rare and has not been well documented in veterinary medicine. Here we describe 6 canine gliomas with cribriform plate involvement (compression or infiltration) and caudal nasal invasion confirmed by neuroimaging, autopsy, and/or histology. All affected dogs were adults (9-12-y-old), and 3 were brachycephalic. Clinical signs were associated with the brain tumor, with no respiratory signs reported. Magnetic resonance imaging in 2 patients revealed a rostral intraparenchymal telencephalic mass with extension into the cribriform plate. All dogs were euthanized. Gross changes consisted of poorly demarcated, white or pale-yellow, soft, and, in oligodendrogliomas, gelatinous, intraparenchymal masses that expanded the rostral portions of the telencephalon and adhered firmly to the ethmoid bone and cribriform plate. Gliomas were classified as high-grade oligodendrogliomas (4 cases) and high-grade astrocytomas (2 cases) based on histology and immunohistochemistry for OLIG2 and GFAP. In all cases, there was evidence of cribriform plate invasion and, in one case, additional invasion of the caudal nasal cavity.

Systemic histiocytic disorder in a jaguar (Panthera onca).

A 7-year-old captive female jaguar (Panthera onca) was presented with a 7-day history of dyspnoea and weight loss. Clinical examination revealed hepatomegaly and elevated serum alanine aminotransferase activity. Pulmonary ultrasonography revealed comet-tail images and an alveolar pattern was detected on thoracic radiography. Due to the poor prognosis, the jaguar was euthanized after 10 days. At necropsy, the main gross findings were hepatomegaly, splenomegaly and multifocal to coalescent, slightly elevated grey areas in the lungs. Histological examination revealed neoplastic proliferation of pleomorphic histiocytes arranged in cohesive sheets in the lungs, liver, spleen, kidneys and lymph nodes. Neoplastic cells had intense immunolabelling for vimentin and ionized calcium-binding adaptor molecule 1, and were immunonegative for pancytokeratin, E-cadherin, CD20, CD3 and CD79α. These findings were compatible with a systemic histiocytic disorder, distinct from any well-defined histiocytic proliferative disease in domestic animals.

Pathological Aspects and Immunohistochemical Evaluation of Troponin C in the Cardiovascular System of Dogs With Pheochromocytoma.

Functional pheochromocytomas secrete catecholamines and have been associated with cardiovascular lesions in dogs. This study aimed to describe the postmortem pathological findings in the cardiovascular system of dogs with pheochromocytoma and to evaluate the expression of cardiac troponin C in these dogs using immunohistochemical analysis. Twelve cases were identified, with a mean age of 10.6 years. The heart of all dogs was enlarged and with concentric hypertrophy of the left ventricular myocardium. Histological analysis showed cardiomyocyte necrosis and degeneration in the myocardium, with frequent bands of contraction, fibrosis, inflammation, and thickening of the medium-caliber arteries in the myocardium. There was a marked decrease or absence of immunolabeling in necrotic cardiomyocytes. We conclude that IHC for troponin C can be a useful tool for detecting myocardial necrosis in dogs with pheochromocytomas, including early cases of necrosis with only incipient cardiac changes where overt histologic abnormalities are not immediately apparent in the cardiomyocytes.

Ophthalmic and immunopathological characterization of systemic infectious diseases in cats.

Ocular involvement in systemic diseases is frequent in cats; however, without concurrent clinical and ophthalmic examinations with gross and/or histologic analysis of the eye, these findings can be underdiagnosed. This article aims to provide gross, histologic, and immunohistochemical characteristics of ocular lesions from cats submitted to necropsy, focusing on those caused by systemic infectious agents. Cats that died due to a systemic infectious disease were selected based on necropsy diagnosis and presence of ocular lesions. Gross, histologic, and immunohistochemical findings were recorded. From April 2018 to September 2019, 849 eyes of 428 cats were evaluated. Histologic abnormalities were seen in 29% of cases, which were classified as inflammatory (41%), neoplastic (32%), degenerative (19%), and metabolic/vascular (8%). Macroscopic changes were present in one-third of eyes with histologic lesions. Of these, 40% were attributed to inflammatory or neoplastic diseases associated with infectious agents. The most important infectious agents causing ocular disease in this study were feline leukemia virus, feline infectious peritonitis virus, and Cryptococcus sp. The most common ocular abnormalities associated with infectious agents were uveitis (anterior, posterior, or panuveitis), optic neuritis, and meningitis of the optic nerve. Ocular lesions secondary to systemic infections in cats are frequent; however, these are not always diagnosed because gross lesions are less common than histologic lesions. Therefore, both gross and histologic evaluation of the eyes of cats is recommended, mainly for cases in which the clinical suspicion or necropsy diagnosis suggests that an infectious agent might be related to the cause of death.

Pathological and immunohistochemical characterization of pancreatic carcinoma in cats.

The aim of this study was to characterize the pathological and immunohistochemical aspects of pancreatic carcinoma in cats, through a retrospective study. From January 2010 to December 2021, 1,908 cat necropsies were performed, in which 20 cases of exocrine pancreatic neoplasia were diagnosed (1.04%). Affected cats were mature adults and seniors, except for one 1-year-old cat. In 11 cases the neoplasm was a soft, focal nodule on the left (8/11) or right (3/11) lobe. In nine cases there were multifocal nodules throughout the pancreatic parenchyma. The size of the single masses ranged from 2 to 12 cm, and the multifocal masses from 0.5 to 2 cm. The most frequent tumour type was acinar carcinoma (11/20), followed by ductal carcinoma (8/20), undifferentiated carcinoma (1/20) and carcinosarcoma (1/20). On immunohistochemical evaluation, all the neoplasms were remarkably reactive to pancytokeratin antibody. The ductal carcinomas were strongly reactive for cytokeratins 7 and 20, which proved to be a good marker for pancreatic ductal carcinoma in cats. The main form of metastasis was abdominal carcinomatosis, with a marked invasion of blood and lymphatic vessels by neoplastic cells. Our findings reinforce the fact that pancreatic carcinoma should be rated highly in the differential diagnosis in mature adult and senior cats with abdominal masses, ascites and/or jaundice.

Verminotic pneumonia in South American fur seal (Arctocephalus australis) in Southern Brazil.

Verminotic pneumonia caused by Parafilaroides spp. nematodes is an underreported disease in beached South American fur seals, with scant literature available on the characteristics of parafilaroidiasis, the nematode itself, as well as its occurrence in pinnipeds in Brazil. The present work aims to identify, describe and detail the histological features of the infection and molecular characteristics of verminotic pneumonia in the South American fur seal. Twenty-six specimens of Arctocephalus australis, found dead on the northern coast of Rio Grande do Sul in 2021, were analysed. These animals were identified and submitted to necropsy and histology. For the molecular identification of metastrongylids, lung fragments were subjected to DNA extraction, polymerase chain reaction targeting the Internal transcribed spacer 2 (ITS-2) gene and subsequent sequencing. In total, 12 animals presented with parasites in the lung parenchyma on histological evaluation, and only 1 showed a granulomatous lung lesion at necropsy. Microscopically, the nematodes were found mainly in the alveoli, associated with little or no inflammatory response, and they had morphological characteristics compatible with metastrongylids. Six ITS-2 gene quality sequences were obtained; after comparative analysis via BLAST, they showed similarity with sequences obtained from Parafilaroides sp. Therefore, verminotic pneumonia caused by Parafilaroides represents an important differential diagnosis of lung disease in South American fur seals found on the northern coast of Rio Grande do Sul.

Feline pulmonary carcinoma: Gross, histological, metastatic, and immunohistochemical aspects.

Feline pulmonary carcinoma (FPC) is an uncommon neoplasm with unique morphological features. We describe the gross, histological, metastatic, and immunohistochemical aspects of FPC, based on postmortem examinations from an 11-year retrospective study. Thirty-nine cases were selected. Predispositions were observed in senior (P < .001) and Persian (P = .039) cats. There were three gross patterns of the pulmonary tumors: (a) a large nodule and additional smaller nodules, (b) a solitary nodule, and (c) small, multifocal to coalescent nodules. Extrapulmonary metastases were present in 22/39 cases (56.4%), mainly in the regional lymph nodes (17/39, 43.5%), skeletal muscles (9/39, 23%), kidneys (6/39, 15.3%), and parietal pleura (4/39, 10.2%). The primary tumor size was correlated with the occurrence of extrapulmonary metastases (P = .002). Histologically, the tumors were classified as papillary adenocarcinoma (19/39, 48.7%), adenosquamous carcinoma (ADS) (8/39, 20.5%), acinar adenocarcinoma (6/39, 15.3%), solid adenocarcinoma (3/39, 7.6%), lepidic adenocarcinoma (2/39, 5.1%), and micropapillary adenocarcinoma (1/39, 2.5%). By immunohistochemistry, 39/39 cases (100%) were positive for pancytokeratin, 34/39 (87.1%) for thyroid transcription factor-1, and 8/39 (20.5%) for vimentin. Immunoreactivity for p40 was detected in the squamous component of all ADSs (8/8, 100%) and occasionally in the glandular component of adenocarcinomas (10/31, 32.2%). Napsin A expression was absent in all feline tissue tested. The results indicate that a modified and simplified histological classification based on current human and domestic animal systems is appropriate for cats. Additionally, this study highlights the utility of p40 as an immunohistochemical marker for the diagnosis of FPC with squamous differentiation.

Eosinophilic Granulomatous Myocarditis in Two Pigs.

Eosinophilic myocarditis is a human condition that has been rarely documented in animals. We now report two unrelated porcine cases of idiopathic eosinophilic granulomatous myocarditis that resembled the human disease and which were associated with sudden death. The most relevant gross finding in both cases was marked cardiomegaly, accompanied by raised, multifocal to coalescent small white nodules (1-2 mm) and poorly demarcated multifocal pale areas in the epicardium. Histologically, there were multifocal to coalescent areas of cardiomyocyte loss with replacement by an intense inflammatory infiltrate of eosinophils and epithelioid macrophages, and proliferation of fibrous connective tissue. Immunohistochemistry for porcine circovirus type 2 (PCV2) and Toxoplasma gondii, in-situ hybridization and quantitative polymerase chain reaction tests for PCV2 and porcine circovirus type 3 and aerobic bacterial culture on myocardium samples were negative.

Pathology of Salmonella enterica Subspecies enterica Serotype Typhimurium Infection in Chinchillas (Chinchilla lanigera).

Septicaemia is the main pathological manifestation of Salmonella infection in chinchillas (Chinchilla lanigera), although information on its pathology is limited. We now describe the gross, histological and immunohistochemical features of Salmonella enterica subspecies enterica serotype Typhimurium (S. Typhimurium) infection in ranched chinchillas. Eighty-five adult pregnant chinchillas had anorexia, prostration, weight loss, hyperthermia and abortion. Necropsy of 13 animals revealed splenomegaly, hepatomegaly, mesenteric lymphadenomegaly, prominent Peyer's patches, pulmonary oedema, white pinpoint lesions in multiple organs and petechiae in the urinary bladder. In all cases, histological lesions were consistent with septicaemia, characterized by acute necrotizing hepatitis, splenitis, lymphadenitis, cystitis, pneumonia, enterocolitis, gastritis and/or nephritis. Immunohistochemistry for Salmonella spp on seven cases revealed intralesional immunolabelling in all affected organs. Salmonella sp was isolated from liver, spleen, intestinal contents and blood of 10 chinchillas. Isolates of four animals were identified as S. Typhimurium.

Duodenal leiomyosarcoma in a cat: Cytologic, pathologic, and immunohistochemical findings.

A 7-year-old mixed-breed neutered male cat was presented with a history of chronic vomiting with increased frequency in the last month, progressing to depression and profuse projectile vomiting. Abdominal ultrasonography revealed an area of marked segmental duodenal thickening associated with a nodule, and euthanasia was performed due to a poor prognosis. Grossly, at the postmortem examination, the wall of a duodenal segment was severely expanded by a nodule measuring 5.0 cm in diameter, resulting in marked luminal narrowing and obstruction. Smears were made by scraping the cut surface of the tumor during the postmortem examination. The smears were highly cellular and contained mesenchymal cells arranged individually or in large non-cohesive aggregates. Cells varied in morphology from spindle to round to stellate-shaped with marked anisocytosis and anisokaryosis. Numerous bi- and multinucleated neoplastic cells were observed. Histologic examination revealed a densely cellular neoplastic proliferation of mesenchymal cells that effaced the duodenal submucosa, muscularis externa, and serosa layers. Most cells were spindle-shaped; however, some tumor areas had numerous round cells and bi- and multinucleated neoplastic cells. Spindle cells showed variable cytoplasmic immunoreactivity for vimentin, smooth muscle actin, and desmin. Round, bi-, and multinucleated giant cells only had marked multifocal cytoplasmic immunoreactivity for vimentin. Neoplastic cells did not have immunoreactivity for cytokeratin, GFAP, S100, and CD117. A final diagnosis of duodenal leiomyosarcoma was made. This article reports the pathologic, cytologic, and immunohistochemical findings of this case and discusses the main differential diagnoses in cases of intestinal sarcomas in domestic animals.

An outbreak of visna-maedi in a flock of sheep in Southern Brazil.

Visna-maedi is a multisystemic and progressive inflammatory disease caused by a non-oncogenic retrovirus (Visna-maedi virus, VMV). An outbreak of visna-maedi occurred in Southern Brazil in sheep with clinical signs of blindness and stumbling gait. At post-mortem examination, all animals had similar lesions, including heavy non-collapsed lungs and multifocal yellow areas in the cerebral white matter, affecting mainly the periventricular region. These lesions corresponded histologically to lymphocytic interstitial pneumonia and histiocytic periventricular encephalitis surrounding areas of necrosis, in addition to significant demyelination in the brain. Serology was performed in all the sheep from the flock and 14% were seropositive for VMV. The presence of VMV was confirmed through PCR and partial sequencing of the 5'LTR. Sequencing demonstrated that the virus had 89.7 to 90.0% of nucleotide identity with VMV strains reported in the USA. This is the first description of clinical disease related to VMV in Brazil leading to economic losses. This study calls for the need to implement control measures to prevent the spread of small ruminant lentiviruses in Brazil.

Causes of death in neotropical primates in Rio Grande do Sul State, Southern Brazil.

BACKGROUND: Anthropogenic disturbances are the main threats to nonhuman primates conservation, and infectious diseases may also play a key role in primate population decline. This study aimed to determine the main causes of death in neotropical primates. METHODS: A retrospective study of post-mortem examinations was conducted on 146 neotropical primates between January 2000 and December 2018. RESULTS: Conclusive diagnoses were obtained in 68.5% of the cases, of which 59 corresponded to non-infectious causes and 41 to infectious diseases. Trauma was the main cause of death (54/100), with anthropogenic stressors caused by blunt force trauma injuries (collision with vehicles) and puncture wound injuries associated with interspecific aggression (dog predation) were the most common factors. Other causes of death included bacterial diseases (27%), followed by parasitic diseases (12%), neoplasms (2%), and viral diseases (2%). CONCLUSIONS: Free-ranging primates were mostly affected by non-infectious causes, while captive primates were by infectious conditions.

Equine abortion associated with placentitis caused by Pasteurella pneumotropica / Aborto equino associado a placentite por Pasteurella pneumotropica

Pasteurella pneumotropica is a bacterium that has so far not been described as a cause of placentitis in animals. Two cases of aborted equine fetuses were sent to the Department of Veterinary Pathology of the "Universidade Federal do Rio Grande do Sul" (SPV-UFRGS) for anatomopathological examination. Both cases presented suppurative placentitis associated with multiple basophilic bacterial cells. After bacterial isolation and biochemical analysis, P. pneumotropica was identified.(AU)

Pasteurella pneumotropica é uma bactéria que até o momento não foi descrita como causa de placentite em animais. Dois casos de fetos equinos abortados foram enviados ao Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS) para exame anatomopatológico. Em ambos os casos se observou placentite supurativa associada a múltiplas colônias bacterianas basofílicas. Após o isolamento bacteriano e análise bioquímica, indentificou-se P. pneumotropica.(AU)

Causes of abortion, stillbirth, and perinatal mortality in horses / Causas de aborto, natimortalidade e morte perinatal em equinos

Causes of abortion, stillbirth, and perinatal mortality in horses were investigated in the Department of Veterinary Pathology of the Federal University of Rio Grande do Sul (SPV-UFRGS) from 2000 to 2015. In this period, 107 cases were analyzed using macroscopic, microscopic, and complementary tests. Of these, 77 were aborted fetuses, 16 were stillbirths, and 14 were perinatal deaths. Conclusive diagnosis was established in 42.8% of the fetuses analyzed, with 28.6% classified as infectious origin, 9.1% as non-infectious, and 5.1% as other. Bacterial infections, especially those related to Streptococcus spp. were the most frequently observed. In stillborn foals, diagnosis was established in 62.5% of cases, and 50% of these were related to non-infectious causes, such as dystocia and birth traumas. As for perinatal mortality, a conclusive diagnosis was reached in 78.57% of cases, and infectious causes associated with bacterial infections accounted for 64.1% of these diagnoses.(AU)

Causas de aborto, natimortalidade e mortalidade perinatal em equinos foram investigadas no Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS) durante o período de 2000 a 2015. Nesse período, foram analisados 107 casos através de exames macroscópico, microscópico e exames complementares, desses 77 correspondiam a fetos abortados, 16 natimortos e 14 mortes perinatais. Diagnóstico conclusivo foi estabelecido em 42,8% dos fetos analisados e classificados como origem infecciosa em 28,6% dos casos, não infecciosa com 9,1% e outros com 5,1% dos casos. As infecções bacterianas, em especial as relacionadas a Streptococcus spp. foram as mais frequentemente observadas. Em potros natimortos, diagnostico foi estabelecido em 62,5% dos casos, e destes, 50% foram relacionados a causas não infecciosas, como distocia e traumas durante o parto. Quanto a mortalidade perinatal, em 78,57% dos casos houve um diagnostico conclusivo, e as causas infecciosas associadas a infecções bacterianas corresponderam a 64,1% desses diagnósticos.(AU)