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MTs are prevalent in dogs, representing the most frequent oral malignancy, compared to cats, in which ocular melanomas predominate. This study investigates the canine and feline MT epidemiology (2005-2024) of cases submitted to the Veterinary Pathology Service (University of Perugia). Among the canine neoplasms, 845 (4%) were melanocytic: 329 (39%) melanocytomas; 512 (61%) melanomas. Of these, 485 (57%) were cutaneous (4% of canine cutaneous neoplasms), 193 (23%) were oral (50% of oral canine neoplasms), and 104 (12%) were mucocutaneous. The average age of affected dogs was 10 years. Older dogs were more likely to have melanomas compared to melanocytomas ( p < 0.001). There were 60 (1%) feline MTs: 6 (10%) melanocytomas; 53 (88%) melanomas. Of these, 29 (48%) were cutaneous (1% of feline cutaneous tumors), 18 (30%) were ocular, and 9 (15%) were oral (22% of feline oral tumors). The average age of affected cats was 11 years. In dogs, mucocutaneous melanomas were more common compared to cutaneous ones ( p < 0.05); oral melanomas were more common compared to all other sites ( p < 0.001). In cats, ocular melanomas were more common compared to cutaneous ones ( p < 0.05). Our study provides the MT prevalence in a selected canine and feline population, revealing MT epidemiological patterns, highlighting species-specific differences in the tumor prevalence, localization, and age distribution.

Background: Meningioma is the most common tumor of the central nervous system of dogs. For this tumor, surgery remains the treatment of choice, either alone or in combination with radiotherapy. Unfortunately, chemotherapeutic strategies are practically absent in dogs and palliative therapies are the only option to surgery. Somatostatin receptor subtype 2 (SSTR2) is expressed in canine meningioma. Since the potent cell-proliferation inhibiting effect of somatostatin (SST), the aim of this study was to investigate in vitro the effects of octreotide, as SST analog, in the viability of canine meningioma., Methods: Four surgical canine meningiomas were used in this study to establish cell cultures. Expression of SSTR2 was verified with immunolabelling in FFPE samples and cell cultures. The effects of octreotide on cell viability were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT). After 24 hours they were exposed to different concentrations of octreotide (0.1 nM, 1 nM, 10 nM, 100 nM) for 24 and 48 hours., Results: All meningiomas consisted of grade I tumors. The cultured neoplastic cells expressed SSTR2 from 80% to 100%. Octreotide significantly increased cell death after 48 hours of continuous exposure, with 10 and 100 nM octreotide doses. The percentage of cell viability was 80.92 ± 4.9 and 80.49 ± 3.61, compared to the control, respectively, consistent with decreased cell viability of about 20% for both doses., Conclusions: Octreotide reduced the alive neoplastic cultured cells of low-grade canine meningioma in a dose-dependent pattern with continuous exposition for 48 hours. These results support an alternative systemic treatment of meningioma with octreotide in the dog., Competing Interests: The authors declare that they have no conflict of interest, (© The Author(s) 2024. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Canine meningiomas are currently graded using the human grading system. Recently published guidelines have adapted the human grading system for use in dogs. The goal of this study was to validate the new guidelines for canine meningiomas. To evaluate the inter-observer agreement, 5 veterinary surgical pathologists graded 158 canine meningiomas following the human grading system alone or with the new guidelines. The inter-observer agreement for histologic grade and each of the grading criteria (mitotic grade, invasion, spontaneous necrosis, macronucleoli, small cells, hypercellularity, pattern loss and anaplasia) was evaluated using the Fleiss kappa index. The diagnostic accuracy (sensitivity and specificity) was assessed by comparing the diagnoses obtained with the 2 grading systems with a consensus grade (considered the reference classification). The consensus histologic grade was obtained by agreement between 4 experienced veterinary neuropathologists following the guidelines. Compared with the human grading alone, the canine-specific guidelines increased the inter-observer agreement for: histologic grade (κ = 0.52); invasion (κ = 0.67); necrosis (κ = 0.62); small cells (κ = 0.36); pattern loss (κ = 0.49) and anaplasia (κ = 0.55). Mitotic grade agreement remained substantial (κ = 0.63). The guidelines improved the sensitivity in identifying grade 1 (95.6%) and the specificity in identifying grade 2 (96.2%) meningiomas. In conclusion, the new grading guidelines for canine meningiomas are associated with an overall improvement in the inter-observer agreement and higher diagnostic accuracy in diagnosing grade 1 and grade 2 meningiomas., (© 2023 The Authors. Veterinary and Comparative Oncology published by John Wiley & Sons Ltd.)

Toxoplasma gondii and Neospora caninum are apicomplexan protozoa of major concern in livestock and T. gondii is also considered one of the major threats and a public health concern. These protozoa have a wide range of intermediate hosts, including birds. The present work aimed to assess the prevalence of these cyst-forming parasites in migratory and sedentary birds of prey. The skeletal muscle and myocardium of 159 birds of prey from Central Italy, belonging to 19 species and recovered across 6 Wildlife Recovery Centers/Care structures along the Italian migratory route, were collected specifically for molecular (PCR) and for histopathological analysis to detect T. gondii and N. caninum . For the molecular analysis, genomic DNA was extracted. The DNA was tested by sequence typing, targeting GRA6, 529 bp repeated element, B1, PK1, BTUB, SAG2, alt.SAG2, and APICO genes for T. gondii and to end-point PCR targeting NC5 gene for N. caninum . Thirty-seven out of the one hundred and fifty-nine analyzed samples tested positive for T. gondii with a prevalence of 23.27% and nine for N. caninum , with a prevalence of 5.66%. Thirty-two sequences were obtained from the thirty-seven isolates of T. gondii . Among these, 26 presented alleles compatible with type I strain in 1 or more loci, 4 with type II strain and 2 consisted of atypical strains. Toxoplasma gondii genetic variability in birds of prey confirms previous findings of wildlife as reservoirs of atypical strains. Results from the histology showed few protozoal tissue cysts in skeletal muscle (n. 4) and hearts (n. 2).

Hepatosplenitis or inclusion body disease is a fatal disease in owls caused by Columbid alphaherpesvirus 1 (CoHV-1). A few old case reports describe it worldwide. In Italy, knowledge regarding virus circulation and disease development is lacking. Four Eurasian eagle-owls ( Bubo bubo ), two adults and two juveniles, were submitted for postmortem examination showing aspecific clinical signs a few hours before death. Grossly disseminated petechial hemorrhages on serosal surfaces ( n = 4), hepatic and splenic necrosis ( n = 3), bilateral and symmetric necrosis of pharyngeal tonsils ( n = 2), and diffuse and bilateral dark-red discoloration and firmness in lungs ( n = 2) were seen. Tissues were sampled for histology, bacteriology, molecular testing, and transmission electron microscopy (TEM). On histology, disseminated petechial hemorrhages ( n = 4) and necrosis of liver ( n = 3) and spleen ( n = 3) were seen, as well as lympho-histiocytic interstitial pneumonia and meningoencephalitis ( n = 2). Intranuclear inclusion bodies (INIBs) were detected in one case. A panherpesviral PCR led to positive results in one case, identified in sequencing as CoHV-1. On TEM, intranuclear and intracytoplasmic virions with herpesviral morphology were seen in the same case. For the other three birds, the lack of PCR positivity, INIBs, and TEM detection could be linked to a possible reduction of the virus to undetectable levels. Death possibly occurred secondarily to bacterial infections, supposedly established during the acute phase of CoHV-1 infection. This paper reports the presence of CoHV-1in Italy and the development of a fatal form of the disease in a Eurasian eagle-owl.

West Nile virus (WNV) and Usutu virus (USUV) are mosquito-borne flaviviruses that have been associated with neurological diseases in humans and wild birds. Wild bird rescue centers are potential significant hot spots for avian infection surveillance, as recognized in the Italian Integrate National Surveillance Plan for Arboviruses. Here we report the results of a post-mortem active monitoring study conducted from November 2017 to October 2020 on animals hosted in five wild bird rescue centers of Central Italy. Five hundred seventy-six (n = 576) wild birds were tested by real-time polymerase chain reaction (RT-PCR) for the presence of WNV or USUV RNA fragments. No birds tested positive for USUV RNA (n = 0; 0.00%). Evidence of WNV RNA (Ct value = 34.36) was found in one bird (n = 1; 0.17%), an adult little grebe ( Tachybaptus ruficollis subsp. ruficollis ), that tested WNV positive in December 2019. This study highlights the strategic role of wildlife rescue centers in monitoring both the introduction and circulation of avian emerging zoonotic diseases. In addition, the presence of WNV during the cold season evidences the possible role of birds in overwintering mechanisms in the Italian territory and requires further investigations.

This study aimed to describe the specific localization and anatomical pattern of 24 feline lymphomas of the nervous system for which the immunophenotype was identified by immunohistochemistry investigations to support the potential specific correlation between subtypes and anatomical patterns. In total 10 tumors affected the spinal cord, eight the brain, four the peripheral nerves, one involved both the brain and the spinal cord, and one simultaneously the brain and the optic nerves. Twenty two tumors were primary lymphomas. The affected animals were 8 years of mean age. Tumors developed as an extra-axial mass (11 cases), intra-axial mass (six cases), leptomeningeal lymphomatosis (three cases), and neurolymphomatosis (five cases). One of them expressed both leptomeningeal lymphomatosis and neurolymphomatosis patterns. Two intra-axial brain lymphomas showed an angiotropic pattern. The optic chiasm was the most involved site for neurolymphomatosis. Immunolabeling was performed using anti-CD3, CD20, CD79a, PAX5, MUM-1, CD56, and anti-CD44 antibodies. In total, 12 tumors consisted of B cell lymphomas, and six of T cell lymphomas, two cases were double-reactive lymphomas while two cases consisted of non-B non-T lymphomas. B cell lymphoma affected animals of 6.4 years of mean age, while the T cell lymphoma affected older animals (mean age of 11.1 years). Extra-axial tumors mainly consisted of B cell lymphomas (8/11). Neurolymphomatosis expressed different immunophenotypes, and the B cell phenotype was the most prevalent in the optic chiasm. Two leptomeningeal lymphomatoses expressed T cell immunophenotype. For the first time, plasmacytoid differentiation was found for angiotropic lymphoma and neurolymphomatosis. All the cases, except one, were CD56-negative. CD44-expression confirmed a common malignant potential for all the anatomical patterns of the nervous system lymphoma in cats. Immunophenotype of feline lymphoma of the nervous system and its potential association with specific anatomical patterns should be strongly required in the diagnostic workup and clinical approach to this tumor especially when its primary origin is confirmed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Mandara, Domini and Giglia.)

Perineuronal or neuronal satellitosis is the term describing the presence of glial cells in the satellite space surrounding the neuronal perikaryon. Confusingly, this finding has been described both as a physiologic and pathologic condition in humans and animals. In animals, neuronal satellitosis has been described in mammals, as well as in avian species. For the latter, the authors wondered whether neuronal satellitosis is expressed in the normal telencephalon of different avian orders and families and whether this pattern in different species shows a specific brain-region association. For these aims, this study explored the presence of neuronal satellitosis in the major areas of the healthy telencephalon in wild and domestic avian species of different orders and families, evaluating its grade in different brain regions. Neuronal satellitosis was seen in the hyperpallium and mesopallium as areas with the highest grade. Passeriformes showed the highest grade of neuronal satellitosis compared to diurnal or nocturnal raptors, and Charadriiformes. To clarify the exact role of neuronal satellitosis in animals without neurological disease, further studies are needed.RESEARCH HIGHLIGHTSNeuronal satellitosis is a common finding in the healthy avian telencephalon.Neuronal satellitosis is a species- and brain-region-associated finding in birds.Passeriformes have the highest grade of neuronal satellitosis.

The human grading system is currently applied to canine meningioma, although it has not been validated in dogs. The present study focused on standardising the human grading system applied to canine meningioma. Four veterinary neuropathologists graded 186 canine meningiomas as follows: Grade I tumour, with <4 mitoses/2.37 mm 2 ; Grade II tumour, with ≥4 mitoses/2.37 mm 2 , brain invasion or at least three of the following criteria: sheeting architecture, hypercellularity, small cells, macronucleoli, necrosis; Grade III tumour, with ≥20 mitoses/2.37 mm 2 or anaplasia. Slides with grading disagreement were reviewed to define a consensus diagnosis and to assess reproducible criteria. Concordance between histologic grade and the consensus diagnosis, as well as intra- and inter-observer agreements for each criterion, were statistically analysed. Concordance between histologic grade and consensus diagnosis ranged from 59% to 100%, with lower concordance for Grade I and II tumours. The lowest inter-observer agreement was recorded for macronucleoli, small cells, hypercellularity and sheeting architecture. Tumour invasion and necrosis displayed fair agreement, while moderate agreement was reached for mitotic grade and anaplasia. The following recommendations were issued to improve the reproducibility of canine meningioma grading: (1) Assess mitotic grade in consecutive HPFs within the most mitotically active area; (2) Define invasion as neoplastic protrusions within central nervous tissue without pial lining; (3) Report spontaneous necrosis; (4) Report prominent nucleoli when visible at ×100; (5) Report pattern loss when visible at ×100 in >50% of the tumour; (6) Report necrosis, small cells, hypercellularity and macronucleoli, even when focal; (7) Report anaplasia if multifocal., (© 2022 John Wiley & Sons Ltd.)

A 4 yr old male Maltese dog presented with a 1 wk history of intermittent neck pain and progressive difficulty walking. Neurologic evaluation was consistent with a left-sided brainstem lesion. On oral examination, left lingual hemiatrophy was evident suggesting hypoglossal nerve involvement. A dumbbell-shaped extra-axial mass in the left side of the caudal fossa extending extracranially through the hypoglossal canal was detected by MRI. At postmortem histologic examination, the hypoglossal nerve was diffusely infiltrated by fusiform neoplastic cells arranged in Antoni A and Antoni B patterns. This is the first description of a malignant nerve sheath tumor selectively involving the hypoglossal nerve in a dog., (© 2022 by American Animal Hospital Association.)

Two Eurasian Blackbirds (Turdus merula) from central Italy were found with severe cyclocoelid trematodosis associated with airsacculitis. The birds were submitted with severe respiratory distress; one died shortly after hospitalization, while the second bird was euthanized. At necropsy, a massive presence of cyclocoelid flukes was observed in the coelomic cavity and air sacs of both birds. The air sacs were diffusely opaque, thickened, and covered by scant fibrinous exudate mixed with numerous parasites. Histologically, the air sacs showed diffuse and severe oedema with fibrinous exudate. Diffuse mononucleated and heterophilic infiltration mixed with multiple granulomas contained degenerated trematodes. Morishitium polonicum was identified using morphologic keys and molecular analysis of extracted DNA. Infections caused by M. polonicum are poorly documented in blackbirds and the findings in these birds support the pathogenic role of this trematode as a potential cause of death in blackbirds in Italy. Extended epidemiologic surveys are required to properly assess the potential importance of M. polonicum as a life-threatening pathogen in Blackbird populations., (© Wildlife Disease Association 2021.)

MicroRNAs (miRNAs) are small non-coding RNAs that play key roles in tumorigenesis as modulators of cell signaling pathways. miRNA expression has been found to be dysregulated in several human and canine tumors, but data are not yet available on canine meningioma. In this study, we analyzed the expression of 12 miRNAs (i.e. miR-335, miR-200a, miR-98, miR-96, miR-190a, miR-29c, miR-219-5p, miR-155, miR-146a, miR-145, miR-136, miR-451) by RT-qPCR in a series of 41 formalin-fixed, paraffin-embedded canine meningiomas, and normal arachnoid samples. We identified 8 dysregulated miRNAs that might be involved in canine meningioma pathogenesis. Five miRNAs (i.e. miR-96, miR-145, miR-335, miR-200a, miR-29c), were downregulated in tumor samples and 3 (i.e. miR-136, miR-155, miR-146a) were upregulated. Moreover, miR-200a was overexpressed in grade III compared to grade I and grade II meningiomas, suggesting that it might have a dual role in tumor initiation and progression. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses suggest that dysregulated miRNAs might influence cellular processes and pathways mainly involved in tumor cell migration, extracellular matrix interactions, cell proliferation, and inflammatory responses. The characterization of miRNA functions in canine meningiomas is needed to assess their potential clinical utility, also in view of the relevance of the dog as a potential spontaneous animal model of human disease., (© 2021 American Association of Neuropathologists, Inc. All rights reserved.)

Background: Equine grass sickness (EGS) has been reported in several European and extra-European countries. Despite this, no scientific paper about clinical cases of EGS in Italy has been published. EGS is a disease affecting almost exclusively horses kept on pasture, characterized by clinical signs related to lesions in autonomic nervous system (ANS), particularly in the enteric nervous system (ENS). According to clinical presentation, acute, subacute and chornic syndromes can be observed, with various sympthoms including dullness, anorexia, dysphagia, drooling of saliva, tachycardia, ptosis, patchy sweating and muscle fasciculations. In horses affected by acute forms, mild to moderate abdominal pain and large volumes of nasogastric reflux can be observed. The etiology is still speculative and many hypothesis have been proposed to explain the pathogenesis., Case Presentation: The present study describes four cases of EGS (one subacute and three chronic forms) occurred in Central Italy during early spring. In all the cases included in the study, the prognosis was poor and the horses were euthanized. The diagnosis was confirmed by histological examination of ANS or ENS. In two cases, in vivo diagnosis was obtained by histological examination of enteric bioptic samples collected during laparoscopy., Conclusions: EGS in Italy could be underdiagnosed and incidence understimated. Greater awareness should be applied in Italy for the inclusion of EGS in differential diagnosis for horses presenting clinical signs of abdominal pain associated or not with gastric reflux and muscular fasciculation. All the cases in this study concerned horses kept in the same pasture, confirming a possible premise-linked and management-linked factors on the ethiopathogenesis of EGS. The age of horses ranged from 2 to 6 years, that is consistent with the risk factor age for EGS (from 2 to 7 years of age). Previous suspected EGS diagnosis in the same livestock and recent cool dry weather were considered additional potential risk factors., (© 2021. The Author(s).)

The Usutu virus (USUV) is a mosquito-borne zoonotic flavivirus. Despite its continuous circulation in Europe, knowledge on the pathology, cellular and tissue tropism and pathogenetic potential of different circulating viral lineages is still fragmentary. Here, macroscopic and microscopic evaluations are performed in association with the study of cell and tissue tropism and comparison of lesion severity of two circulating virus lineages (Europe 3; Africa 3) in 160 Eurasian blackbirds (Turdus merula) in the Netherlands. Results confirm hepatosplenomegaly, coagulative necrosis and lymphoplasmacytic inflammation as major patterns of lesions and, for the first time, vasculitis as a novel virus-associated lesion. A USUV and Plasmodium spp. co-infection was commonly identified. The virus was associated with lesions by immunohistochemistry and was reported most commonly in endothelial cells and blood circulating and tissue mononucleated cells, suggesting them as a major route of entry and spread. A tropism for mononuclear phagocytes cells was further supported by viral labeling in multinucleated giant cells. The involvement of ganglionic neurons and epithelial cells of the gastrointestinal tract suggests a possible role of oral transmission, while the involvement of feather follicle shafts and bulbs suggests their use as a diagnostic sample for live bird testing. Finally, results suggest similar pathogenicity for the two circulating lineages.

Human hypothalamic neuronal hamartomas are rare, nonprogressive, congenital malformations of the hypothalamus that do not expand or metastasize to other locations. A 1 yr old female vizsla was presented for progressive intracranial multifocal neurological signs present since adoption at 3 mo of age. MRI of the brain showed an ill-defined, intra-axial, space-occupying, nonenhancing lesion located in the ventral middle cranial fossa. Histopathological examination was consistent with hypothalamic neuronal hamartoma. This is the first report describing clinical, imaging, and histopathological features of a hypothalamic neuronal hamartoma in a dog. These findings are compared with their human counterparts., (© 2021 by American Animal Hospital Association.)

Epithelial membrane antigen (EMA) is one of the most widely used diagnostic immunohistochemical markers for human meningioma. To date, no published study on EMA expression in formalin-fixed paraffin-embedded (FFPE) tissue samples of canine meningioma is available. Here, we describe the results of an immunohistochemical study on 25 FFPE canine meningiomas using a monoclonal anti-human EMA antibody. All meningiomas showed positive staining for EMA with cytoplasmic pattern, in nine cases associated with membranous staining. Area and intensity of staining were highly variable among cases. No clear relationships between tumour subtype/grade and area/intensity of staining were found. However, epithelial-like patterns showed a higher affinity for EMA compared to the mesenchymal one. The present study provides the basis to explore the potential diagnostic application of this marker in canine meningioma. To investigate EMA expression in other central nervous system tumours of dogs are necessary to assess the specificity of this marker., (© 2020 John Wiley & Sons Ltd.)

The objectives of this study were to evaluate in horse testes the expression of kisspeptin (KiSS) and GnRH1 neuropeptides and their cognate receptors, KiSS1R and GnRH1R, as well as their action on testosterone, GnRH1, prostaglandin F2α (PGF2α), and PGE2 synthesis and cyclooxygenase 1 (COX1) and COX2 activity by Leydig cells in vitro. Testes were obtained from 9 sexually mature horses by surgical castration. Immunohistochemistry, evidenced the presence of KiSS, KiSS1R, GnRH, and GnRH1R in Leydig cells, whereas germinal and Sertoli cells were positive only for GnRH1. Transcripts for both neuropeptides and their cognate receptors were revealed in isolated Leydig cells by RT-PCR. Isolated and purified Leydig cells were in vitro cultured with agonists and antagonists of KiSS (KiSS-10 and KiSS-234, respectively) and GnRH1 (buserelin and antide, respectively). KiSS-10 and buserelin increased (P < 0.01) COX1 activity and testosterone and PGF2α basal secretion, while decreased (P < 0.01) that of PGE2. KiSS-10 and buserelin did not affect COX2 activity. GnRH1 basal production was increased (P < 0.01) by KiSS-10, but not by buserelin. Antide counteracted the KiSS and GnRH1 effects, whereas KiSS-234 influence only those of KiSS. Summarizing, the KiSS/GnRH1 system is present in horse Leydig cells and modulates their endocrine activity. In particular, the endocrine effects of KiSS are mediated by GnRH1, so suggesting that hypothalamic-like interaction between KiSS and GnRH1 occurs also in Leydig cells., (Copyright © 2020. Published by Elsevier Inc.)

Squamous cell carcinoma (SCC) is a malignant mucoepithelial tumor that affects pets and farm animals. Common sites are dorsal areas and/or areas of poor skin pigmentation exposed to mutagenic ultraviolet (UV) radiation. Novel ovine papillomavirus (OaPV3) was recently described in SCC lesions in Sardinia breed ovines. In 2017, a 7‑year‑old half‑breed aries was presented with symptoms compatible with a vestibular syndrome. The animal was euthanized 1 month after the onset of clinical signs due to a lack of response to treatment and poor prognosis. A complete postmortem examination was performed. Necropsy revealed only a loss of incisors, associated with alveolar necrotic osteomyelitis, and left unilateral purulent nasal discharge. No other thoracic or abdominal lesions were observed. Opening of the skull revealed a cauliflower‑like space‑occupying mass. Histological examination showed trabecules and islands of squamous, neoplastic epithelial cells with the formation of concentric keratin layers. This raised the suspicion of SCC, which was confirmed with cytokeratin‑positive immunostaining. Simplex PCR on the frozen tissue mass was negative for OaPV1, OaPV2, and OaPV3. This case report suggests that SCC, although rare, should be included in the differential diagnosis of cases of vestibular disorder.

Dogs develop gliomas with similar histopathological features to human gliomas and share with them the limited success of current therapeutic regimens such as surgery and radiation. The tumor microenvironment in gliomas is influenced by immune cell infiltrates. The present study aims to immunohistochemically characterize the tumor-infiltrating lymphocyte (TIL) population of naturally occurring canine gliomas, focusing on the expression of Forkhead box P3-positive (FOXP3+) regulatory T-cells (Tregs). Forty-three canine gliomas were evaluated immunohistochemically for the presence of CD3+, FOXP3+, and CD20+ TILs. In low-grade gliomas, CD3+ TILs were found exclusively within the tumor tissue. In high-grade gliomas, they were present in significantly higher numbers throughout the tumor and in the brain-tumor junction. CD20+ TILs were rarely found in comparison to CD3+ TILs. FOXP3+ TILs shared a similar distribution with CD3+ TILs. The accumulation of FOXP3+ Tregs within the tumor was more pronounced in astrocytic gliomas than in tumors of oligodendroglial lineage and the difference in expression was significant when comparing low-grade oligodendrogliomas and high-grade astrocytomas. Only high-grade astrocytomas presented FOXP3+ cells with tumoral morphology. In spontaneous canine gliomas, TILs display similar characteristics (density and distribution) as described for human gliomas, supporting the use of the dog as an animal model for translational immunotherapeutic studies., (© 2019 American Association of Neuropathologists, Inc. All rights reserved.)

Background: Despite being one of the major causes of infertility in mares, the mechanisms responsible for equine endometrosis are still unclear and controversial. In the last few years, many investigations focused on local immune response modulation. Since it is generally accepted that endometrial fibrosis increases with age, we hypothesize that older mares could show altered local immune modulation, initiating a pro-inflammatory and tissue remodeling cascade of events that could lead to endometrosis. The aim of this study, indeed, is to evaluate and describe the local gene expression of genes involved in acute inflammatory response and fibrosis (COL1A1, COL3A1, TNFA, MMP9, IL6, TGFB1 and TGFBR1), together with others associated to immune modulation (DEFB4B, IDO1 and FOXP3), in uterine specimens from mares of different age., Results: Twenty-five Standardbred mares were involved in the study with age ranging from 7 to 19 years (mean 10.40 ± 4.42). They were divided by age into two groups: G1 (n = 15, less than 10 years old) and G2 (N = 10, greater than 11 years old). Specimens from the uterus' right horn-body junction were collected and processed for histology evaluation and RT-qPCR assay.Gene expression of DEFB4B, MMP9 and TNFA was higher in younger mares, suggesting a balance in immune modulation and tissue remodeling. Interleukin-6 and COL3A1 gene expressions were greater in older animals, probably indicating inflammatory pathways activation and fibrosis increase. Although no differences in fibrosis and inflammation distribution could be found with histological examination among G1 and G2, our results suggest a possible involvement of DEF4BB in regulating the local immune response in younger mare's uterus (G1); age may contribute to the dis-regulation of DEFB4B transcription and, indirectly, influence the extracellular matrix homeostasis. Transcription of IDO1 and FOXP3 genes, instead, does not seem to be age related, or to be involved in local immune-response and tissue remodeling functions., Conclusions: Further investigations are needed in order to clarify the interactions between the expression of DEFB4B, IL6, TNFA, COL3A1 and MMP9 and other local signals of immune-modulation and tissue remodeling, in mares in a prospective study design.

A 4-month-old puppy died after showing intracranial signs a few days after a suspected viral enteritis. Grossly, the right cerebral hemisphere had a large irregular cavity external to the internal capsule. Histopathological examination revealed a cystic lesion in the right hemisphere and non-suppurative inflammation of the diencephalon and periaqueductal nervous tissue. Porencephaly associated with periventricular non-suppurative encephalitis was diagnosed. A nested polymerase chain reaction (PCR) identified the presence of parvovirus DNA in the brain and real-time PCR typed this as canine parvovirus (CPV) type 2a. Immunohistochemistry revealed the presence of CPV antigen in the cytoplasm of scattered cells in the subependymal layers and choroid plexus epithelium. The porencephaly was not associated with inflammatory lesions or CPV antigen and was considered to have preceded the neurological signs. In contrast, the detection of CPV antigen in the subependymal layers and choroid plexus epithelium supported the association of this virus with the periventricular encephalitis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The neuropeptide somatostatin (SST) plays an important regulatory role in the proliferation of normal and neoplastic cells. Five subtypes of somatostatin receptors (SSTRs), SSTR1-SSTR5, have been identified in human tumours. The SSTR2 subtype is identified most commonly in meningiomas. Long half-life SST analogues are now recommended for the systemic treatment of unresectable or radiation-refractory recurrent human meningiomas. In this study, SSTR2 expression was evaluated in 46 canine meningiomas; in 21 cases this was by immunohistochemistry and in 25 cases by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). In addition, SSTR2 expression was evaluated by immunocytochemistry, western blotting and RT-qPCR on primary cell cultures prepared from two canine meningiomas. SSTR2 immunohistochemical expression was observed in 17/21 cases (81%), and SSTR2 mRNA expression was detected in 14/25 cases (56%). SSTR2 protein and gene expression were not significantly correlated with the tumour histological subtype or grade. Overall, meningothelial meningiomas showed constant and diffuse SSTR2 immunohistochemical expression and the highest SSTR2 gene expression level compared with other subtypes. A tendency for loss of SSTR2 in high-grade meningiomas was observed in both immunohistochemical and RT-qPCR studies. About 90% of cultured canine meningioma cells showed SSTR2 expression. In both of the meningioma cell cultures, SSTR2 expression was also detected by western blotting and RT-qPCR. This study demonstrates for the first time that canine meningioma expresses SSTR2 and that this expression is maintained in vitro. Our results, while preliminary, provide encouragement for further studies aimed at finding novel medical treatment strategies for canine meningioma, especially for tumours that are not surgically accessible., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Meningioma is the most common primary brain tumor in cats and occurs less frequently in the spinal cord. This study aimed to investigate cyclooxygenase-2 (COX-2) expression in feline meningiomas, and the possible association between COX-2 immunoreactivity and tumor grade using eight low-grade and seven high-grade meningiomas. All tumors (n=15/15) were immunoreactive to COX-2. The expression of COX-2 was not significantly correlated with tumor grade (P=0.22 and 0.34 for staining and intensity, respectively) but was significantly associated with necrosis (P=0.04 and 0.01 for staining and intensity, respectively). The findings in this study suggest that feline meningiomas express COX-2, but there were no differences in COX-2 immunoreactivity patterns between low- and high-grade meningiomas. However, the association between COX-2 expression and the presence of necrosis indicates a potential area for therapeutic intervention with selective COX-2 inhibitors., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The aim of this study was to delineate the pattern of sympathetic innervation in the suprasesamoidean region of the deep digital flexor tendon (DDFT) in horses with tendinopathy by immunohistochemical labelling for tyrosine hydroxylase (TH) and α-1 adrenergic receptor (α1-AR). Twelve forelimbs were obtained from 10 horses with DDFT tendinopathy and six feet obtained from six horses were used as healthy controls. Post-mortem radiographic, ultrasonographic and gross examinations were performed on the suprasesamoidean area of the DDFT to assess the presence of tendinopathy. Longitudinal sections were collected and processed. Lesions were classified as core lesions, dorsal border lesions and parasagittal oblique splits. Immunohistochemistry was performed and the degree of immunoreaction was classified as absent, mild or marked. Seven core lesions, four dorsal border lesions and one parasagittal oblique split were identified. There was no increased expression of sympathetic innervation in samples with a dorsal border lesion of the DDFT compared with healthy samples. In contrast, core lesions showed increased expression of α1-AR and reduced expression of TH, which supports the hypothesis of a compensatory imbalance between the sympathetic mediator and the sympathetic receptors as a cause or effect of structural damage. In addition, adrenergic activation could stimulate cell proliferation and differentiation within these lesions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Choroid plexus tumors (CPT) are intraventricular neoplasms accounting for 10% of all primary central nervous system tumors in dogs. They are frequently classified according to the human WHO classification into choroid plexus papilloma (CPP, grade I), atypical CPP (aCPP, grade II), and choroid plexus carcinoma (CPC, grade III). Histological features observed in canine CPT such as increased vascular density (IVD) and glomeruloid microvascular proliferation (GMVP) are not part of the WHO classification. This multi-centric study aimed to investigate tumor-associated vascular hyperplasia in dogs by determining the prevalence of GMVP and IVD in 52 canine CPT and their association with tumor grade. In addition, the expression of angiogenic factors was assessed by immunohistochemistry in 25 tumors to investigate the pathogenesis of tumor-associated vascular hyperplasia. Based on the classical histological hallmarks, this study of 52 CPT identified 22 (42%) CPP (grade I) and 30 of (58%) CPC (grade III). GMVP was more prevalent in CPC (13/30; 43%) than CPP (1/22; 4%), whereas IVD occurred to a similar extent in CPP and CPC. Desmoplasia was more common in CPC (19/30; 63%) than CPP (2/22; 9%), and similarly, the proliferative index (PI) of neoplastic epithelium was significantly higher in CPC (5.14%) than CPP (0.94%). The majority of CPT expressed platelet-derived growth factor (PDGF), PDGFRα, PDGFRβ, and vascular endothelial growth factor (VEGF) irrespective of tumor grade or tumor-associated vascular hyperplasia. These results suggest that tumor-associated GMVP, desmoplasia, and PI may serve as histological indicators of malignancy in CPT.

Background: Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are considered to be key mediators of tumor invasion and metastasis. MMP-2 and MMP-9 are expressed in meningiomas of dogs, but TIMP expression, and variations of specific MMP/TIMP ratios still are unknown in this tumor., Hypothesis/objectives: Expression of MMP/TIMP might increase progressively from grade I to grade III meningioma. Therefore, genetic expression of MMP-2 and MMP-9, and specific TIMP-2 and TIMP-1, respectively, has been investigated in meningiomas of different grades., Animals: Selected formalin-fixed paraffin-embedded tissue from 43 meningiomas of dogs was evaluated., Methods: Genetic material was obtained from pathologic samples and used for quantitative reverse transcriptase real-time polymerase chain reaction (RT-qPCR)., Results: MMP-9 was not expressed in all of the tumors, but MMP-2 was significantly more expressed in papillary meningioma. Likewise, the MMP-2/TIMP-2 ratio was numerically higher in papillary meningiomas compared to all grades (>3.5 times) showing a strong bias in favor of metalloproteinase. In the papillary meningioma, TIMP-1 gene expression was significantly higher than in grades I and III., Conclusions and Clinical Importance: MMP-2/TIMP-2 imbalance might contribute to the aggressive biologic behavior of papillary meningiomas in dogs. TIMP-1 expression may play a role independent of MMP-9 expression in neoplastic progression. These results further support that therapeutic and prognostic evaluations of dogs with meningioma need to be addressed according to different histologic patterns as is performed in humans., (Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

A diffuse bilaterally symmetrical leukomyeloencephalopathy was observed in a 6-year-old male Azawakh dog showing a slowly progressive ataxia of six months duration associated with sensory disorders. Severe bilaterally symmetrical demyelination and vacuolisation were confined to the dorsal columns along the entire spinal cord with a minor axonal degeneration. The main changes of myelin sheaths consisted in splitting and intramyelin vacuolization. Naked axons were scattered in a network of astrocytic processes and collagen fibres. Few reactive macrophages exhibiting a foamy pattern were observed adjacent to the small vessels. In the brain, cuneatus nuclei showed a number of atrophic neurons. A spongy change was observed in the raphe nuclei, spinal tract and nuclei of trigeminal nerve, and caudal cerebellar peduncles. Lesions there were neither in the spinal and trigeminal nerves, nor in the spinal ganglia. Although in the absence of a pedigree analysis support an inherited cause cannot be completely excluded., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In cats, lymphoma (lymphosarcoma) is the most common neoplasm affecting the spinal cord and the second most common intracranial tumour. Although lymphoma commonly develops in the spinal cord as a part of a multicentric process, a primary form may occur. Lymphoma can exhibit a wide range of morphological patterns, including intraparenchymal brain mass, lymphomatosis cerebri, intravascular lymphoma, lymphomatous choroiditis and meningitis, extradural, intradural-extramedullary or intramedullary lymphoma in the spinal cord, or neurolymphomatosis in the peripheral nerves. Lymphoma may occur as a paraneoplastic disorder associated with peripheral neuropathies. Magnetic resonance imaging (MRI) and computed tomography (CT) are the techniques of choice for morphological assessment of nervous system lesions in vivo. However, biopsy should be performed to achieve a definitive diagnosis. Knowledge of the different morphological patterns expressed by lymphoma in the nervous system of cats allows veterinary clinicians to suspect lymphoma and to arrange appropriate diagnostic procedures, including immunophenotype and clonality studies, along with therapeutic protocols and prognostic evaluations., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Choroid plexus tumors (CPTs) are reported with an increasing incidence in dogs, and they call for a reexamination of histologic features and criteria of classification corresponding to their biological behavior. In this study, the human World Health Organization classification was applied to 16 canine CPTs, and the expression of molecules involved in neoplastic cell adhesion (E-cadherin, N-cadherin), invasion (doublecortin), and proliferation (Ki-67) was investigated. Mitotic index was found to be the main criterion for grading CPTs. Cell density and multilayering of papillae were also statistically associated with histologic grade. Intraventricular spread and parenchymal invasion was observed for tumors showing histologic benign features. E-cadherin was expressed in all CPT grades, independent of tumor invasion. N-cadherin immunolabeling was more expressed in grade I than high-grade CPTs, whereas doublecortin expression was not detected in CPTs. An increasing proliferative activity was observed in relation with histologic grade., (© The Author(s) 2016.)

The purpose of this study was to delineate the pattern of sympathetic innervation in the suprasesamoidean region of the deep digital flexor tendon (DDFT) in horses using immunohistochemical staining (IHC) for tyrosine hydroxylase (TH) and alpha-1 adrenergic receptor (α1-AR). Fourteen forelimbs were collected from 10 horses. Longitudinal sections of the suprasesamoidean region of healthy DDFTs were harvested. Most of the sympathetic innervation was found to be in the walls of blood vessels. The tendon tissue proper was sparsely innervated, with a lesser degree of innervation within the dorsal fibrocartilage. Increased α1-AR immunostaining was also detected in walls of blood vessels and in spindle cells of fibrocartilage. Both α1-AR and TH immunostaining were detected in tenocytes. These findings support the presence of autocrine/paracrine catecholaminergic signalling in equine tendon tissue., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Papillary meningioma (PM) is one of the most aggressive variants of meningioma in humans and classified as grade III by WHO system. To date, the biological behavior of PM is still not clear in dogs. This study investigated the correlation between histopathological findings of 16 canine PMs and follow up data. Moreover, the expression of doublecortin, E-cadherin, and N-cadherin was investigated by immunohistochemistry. The supratentorial compartment resulted the most common involved. Despite the low grade of histological malignancy, 87.5% of dogs that underwent surgery experienced tumor recurrence. Intratumoral necrosis was observed in a strict correlation with malignancy histological parameter and tumor recurrence. The post-surgery mean survival time was much lower than thus observed in the most common histological subtypes. This data were also confirmed in dogs that received a conservative treatment alone. Tumors with a severe clinical behavior showed a high N-cadherin expression versus a low or absent E-cadherin expression., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A 7-year-old intact male mixed dog was presented with a history of acute and progressive paraparesis. Abnormal clinical signs consisted of non-ambulatory paraparesis, hind limbs hypertonia and severe thoracolumbar pain. Magnetic resonance imaging demonstrated an isointense in T1 and T2 WI epidural lesion, with good contrast enhancement, extending from T-10 to T-13. Laminectomy was carried out to remove the epidural mass. Histological examination revealed a pyogranulomatous lesion characterized by numerous macrophages containing yeast-like Grocott and PAS-positive bodies. Immunohistochemistry and PCR performed on formalin-fixed paraffin-embedded tissue confirmed Histoplasma capsulatum as the causative agent. H. capsulatum has a worldwide distribution in temperate and subtropical climates but its presence as an autochthonous fungus in Europe is now recognized. To the authors' knowledge this is the first report of canine histoplasmosis in Italy with lesion confined to the central nervous system., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A 1-year-old sexually intact male Korat cat was referred for ophthalmological consultation due to anisocoria. Mydriasis with external ophthalmoplegia and absence of pupillary light responses in the right eye and nasofacial hypalgesia were seen. Cavernous sinus syndrome (CSS) was suspected. Bilateral deformities of the jaw and phalangeal bones, severe spinal pain and abnormal conformation of the lumbar spine were also present. Radiographic examination revealed several mineralised masses in the appendicular and axial skeleton, indicative of multiple cartilaginous exostoses. For further investigation of the CSS-related neurological deficits, the cat underwent computed tomography (CT) examination of the skull. CT images revealed a non-vascularised, calcified, amorphous mass originating from the right lateral skull base and superimposing on the sella turcica. Based on the severity of diffuse lesions and owing to the clinical signs of extreme pain, the cat was euthanased. A diffuse skeletal and intracranial osteochondromatosis was diagnosed histologically.

Clinical, neuroimaging, and neuropathological findings of 2 cases of canine primary diffuse leptomeningeal gliomatosis are described. Magnetic resonance imaging and histopathological examination of the brain revealed diffuse leptomeningeal alterations with no parenchymal involvement. These cases share many similarities with the same disease in humans.

Feline cutaneous nerve sheath tumours (CNSTs) are uncommonly reported in the skin, since they are underestimated relative to the more common spindle cell tumours of soft tissue. In this study, 26 nerve sheath tumours selected from 337 skin neoplasms of cats were examined. Histologically, they were classified into malignant (MPNSTs) and benign tumours (BPNSTs) based on degree of cellular atypia and polymorphism as well as mitotic rate and diffuse necrosis. CPNSTs were tipically characterised by Antoni A pattern, in some cases associated with Antoni B pattern. In the malignant peripheral nerve sheath tumours (MPNSTs) the polymorphism was marked, while it was mild to moderate in the benign forms (BPNSTs). In the MPNSTs the mitotic activity was generally higher than in the BPNSTs. In five cases, including three MPNSTs and two BPNSTs, there were multinucleated giant cells. Necrotic foci occurred in a BPNST and in two MPNSTs, while osseous/chondroid metaplasia was found in two cases. Immunohistochemically, all the tumours showed a marked diffuse vimentin expression. S-100 protein was expressed in 17 cases, including 81.8% of BPNSTs and 57.14% of MPNSTs. Twenty-five tumours expressed NSE and twenty-four cases showed immunoreaction for laminin. Thirteen tumours were positive for GFAP, while five tumours were positive for SMA. PGP 9.5 expression was detected in all cases, except for two MPNSTs. NGFR was expressed in eleven cases, including four MPNSTs and seven BPNSTs. Ki67 was expressed in twenty tumours without any relationship with morphologic malignancy of the neoplasm. In this case series we confirmed neoplastic spindloid cells with wavy cytoplasm arranged in compact areas, with occasional nuclear palisading or whirls, and interchanged with loosely arranged areas, as the morphological features supporting a diagnosis of CPNST. A constant concurrent expression of vimentin, NSE, and laminin might confirm the diagnosis of PNST in the absence of clear S-100 protein positivity, especially in the malignant forms. In this study, conclusive data were not obtained on the diagnostic relevance of NGFR- and PGP 9.5-expression in feline CPNSTs., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

A seven-year-old shar-pei dog was referred because of severe lumbosacral pain and faecal incontinence of 20 days' duration. Neurological examination was characterised by plegic tail, absence of perineal reflex, dilated anus, perineum and tail analgesia, and severe lumbosacral pain. The neurological clinical signs were suggestive of a selective lesion involving sacral and caudal spinal cord segments and/or related nerve roots. A magnetic resonance imaging of lumbosacral spine was performed and was suggestive of an intradural lesion. Primary or secondary neoplasia was considered as the most probable differential diagnosis. The dog was euthanased upon the owner's request. Histopathological examination confirmed the presence of an intradural-extramedullary neoplastic tissue enveloping intradural tract of spinal nerve roots. On the basis of histological and immunohistochemical findings, a diagnosis of well-differentiated choroid plexus papilloma was made. To the authors's knowledge, this is the first case of primary or metastatic spinal choroid plexus papilloma in dogs., (© 2013 British Small Animal Veterinary Association.)

The present paper describes an astrocytic thalamic hamartoma associated with tectal meningoangiomatosis in a 3-month-old female German shepherd dog showing strabismus, opistotonus, circling, and fore limb hypermetria. MR images of the brain showed a well-defined intra-axial mass in the tectal region. The mass was hypointense to gray matter on T2-weighted images and hyperintense to gray matter on precontrast T1-weighted images. Histologically, glial cells arranged in a multinodular pattern characterized the mass. More caudally the lesion merged with subpial abnormal newly formed plaque-like shaped tissue characterized by thick branching bundles of spindle-shaped cells surrounding a central vessel. In the nodules, GFAP and vimentin were diffusely expressed. In the vascular proliferation Factor VIII-positive reaction was limited to endothelial cells while the remaining spindle-shaped cells were diffusely SMA-positive. The glial nodules did not express lysozyme and MAC387, nor neurofilaments and nestin., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A 7-year-old male trotter horse with a history of recurrent colic displayed clinical findings consistent with chronic intestinal pseudo-obstruction (CIP). At laparotomy, an impaction of the descending colon associated with marked atrophy of the right dorsal colon was found. The horse was humanely destroyed and tissues collected at necropsy examination revealed diffuse enteric ganglionitis comprising an infiltrate of CD3(+) T lymphocytes and plasma cells. At all levels of the intestinal tract the number of myenteric ganglia and of normal ganglion cells was decreased significantly. There were chromatolytic or necrotic neurons and the amount of connective tissue surrounding ganglia was increased. Immunohistochemical studies demonstrated slightly reduced expression of neuron-specific enolase and a moderate increase in expression of S100 and glial fibrillary acidic protein in a sample of right dorsal colon taken during the necropsy examination compared with a biopsy sample taken from the same location. Immunolabelling and semi-nested polymerase chain reaction for equine herpesvirus (EHV)-1 performed on the gut were positive, supporting an aetiological relationship between EHV-1 infection and the enteric ganglionitis., (Copyright © 2012 Elsevier Ltd. All rights reserved.)