Search

Background: Dogs and cats are the most common domestic animal species diagnosed with primary neoplasms of the central nervous system. Of these, meningioma is the brain tumor most commonly reported in dogs and is associated with several neurological changes, such as seizures. The ante mortem diagnosis is difficult to make because the use of computerized tomography, the gold standard for the presumptive diagnosis of brain tumors, is still a limited and expensive exam in veterinary medicine. The aim of this study is to report the case of a grade II transitional meningioma in a female dog attended and necropsied at the Veterinary Hospital of the Universidade Estadual de Santa Cruz (HV-UESC). Case: A 13-year-old female Poodle was examined at HV-UESC with a clinical history of prostration, apathy, anorexia, partial vision loss, and neurological abnormalities, including seizures. The dog was being treated with phenobarbital (2 mg/ kg three times a day) for seizures and doxycycline (5 mg/kg twice a day) for anaplasmosis diagnosed prior to clinical care at HV-UESC. On physical examination, the dog was observed to be mentally altered, with increased aggression, walking in large circles to the left, tremors and spasticity of the thoracic limbs. Laboratory analysis revealed a normal complete blood count. Biochemical analysis revealed an increase in alanine aminotransferase (296 U/mL), alkaline phosphatase (286 U/ mL) and urea (121 mg/dL) levels. Based on the clinical and laboratory abnormalities, the suspicion of cerebral degenerative neuropathy or neoplasia was established. The dog was examined again approximately two months after initial presentation and no improvement in the dog's neurological condition was noted; in fact, the dog's condition had deteriorated, which was evidenced by worsening seizures, tetraparesis and bedsores. Due to the severity of the neurological changes, euthanasia was performed. After authorization from the owner, the dog was referred to the HV-UESC Necropsy Department, where the dog was necropsied. The primary macroscopic finding was a well-defined mass measuring approximately 2.5x1.5x1.5 cm in the frontal cortex of the left cerebral hemisphere. The lesion was firm and white with an irregular surface and was adhered to the dura mater. The mass compressed the adjacent brain tissue. Histopathological analysis demonstrated a non- encapsuled, expansive, and partially delimited neoplasm characterized by sheets of meningoendothelial cells arranged primarily in mantles, though sometimes in lobes, in two distinct patterns: meningoendothelial and fibrous. In addition, a moderate amount of psammomatous bodies were observed. These microscopic characteristics led to the diagnosis of a grade II transitional meningioma. Discussion: This report describes a case of meningioma in a female dog, which is the most common type of brain tumor diagnosed in dogs according to the literature. The affected animal was advanced in age, a factor that is associated with an increased risk of developing this neoplasm. The neurological alterations noted in this report were associated with the neoplastic process. The macroscopic finding of a cerebral neoformation was suggestive of neoplasm; this was confirmed by microscopic evaluation of the mass. As has been previously reported, the clinical neurological signs of most cases of suspected brain tumors occur late in the disease process, at which point the neoplasm is already in an advanced stage of development. Thus, the prognosis of the affected animal is poor, as it was in this case, which leads to euthanasia. In summary, this is a report of a case of intracranial transitional meningioma accompanied by progressive neurological alterations, in which an ante mortem diagnosis is difficult due to the limited use of computerized tomography in routine veterinary practice. [ABSTRACT FROM AUTHOR]

The purpose of this retrospective, multicentre case series was to describe the outcome following surgery and/or radiation of spinal meningiomas and nerve sheath tumours (NSTs) based upon treatment modality, with a specific aim to evaluate the survival times and time to recurrence following treatment for each histopathological diagnosis. Our hypothesis was that the addition of radiation therapy modalities to treatment will yield longer time to recurrence of clinical signs and survival time. Thirty‐four dogs met the inclusion criteria of histopathologically diagnosed extramedullary spinal meningioma or NST. Sixteen extramedullary spinal meningiomas and 18 NSTs were diagnosed. A diagnosis of meningioma was associated with a significantly longer survival time compared with NSTs, with median survival times (MST) of 508 days (95% confidence interval [CI]: 66‐881) vs 187 days (95% CI: 76‐433; P = .02). Dogs (seven) treated with stereotactic radiation therapy (SRT) for recurrence after surgery alone or SRT alone as their initial treatment gained an additional 125 to 346 days survival time. [ABSTRACT FROM AUTHOR]

A prospective study to assess high-dose hypofractionated volume modulated arc radiotherapy feasibility and efficacy in canine meningiomas was conducted. Thirty-nine patients with encephalic and spinal meningiomas assumed from MRI findings were recruited and received high-dose hypofractionated volumetric modulated arc radiotherapy by a linear accelerator equipped with an external beam modulator micro-multileaf collimator and an XVI cone beam computed tomography system. The prescribed mean dose was 33 Gy in five fractions. The treatment feasibility was tested through planned and delivered dose agreement checks. Regular clinical examinations were performed during and after irradiation time, with regard to mentation, deambulation, cranial nerve dysfunction, and seizures. Serial MRI exams were done 60 days after irradiation and after 4, 6, 12, 18, and 24 mo. Volumetric disease reduction criteria implemented with clinical neurological systematic evaluation were adopted to assess the course and to categorize patients' responses. Complete and partial responses were observed on the whole in 65.5% of alive patients 24 mo after irradiation. Two-yr overall and disease-specific survival rates were 74.3% and 97.4%, respectively, and the putative radiotoxic effects were found to be few and slight. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The article presents a case study of neutered female Labrador Retriever diagnosed with spinal meningiomas. It mentions that magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) analysis, and cytoreductive surgery with dorsolateral laminectomy were performed. It notes that the dog was treated with gabapentin and prednisolone.

Summary Meningioma is the most common primary brain tumour in the cat. Although most of these tumours are considered to be benign based on histological characteristics, little is known regarding microenvironmental changes associated with the tumour. The characterization of the immune-cell infiltrate in human and canine meningiomas has been described; however, there are no data regarding the cat equivalent. Seventeen formalin-fixed, paraffin wax-embedded samples of feline meningioma were evaluated by light microscopy and immunohistochemistry (IHC) for expression of CD3, Pax5, Iba-1, HLA-DR, MAC387, CD163 and Ki67. Variable immune cell infiltrates were seen in every case. All tumours had moderate numbers of infiltrating CD3 + T lymphocytes. Seven of 17 tumours (41%) had infiltrating PAX5 + B lymphocytes that were often dispersed randomly throughout the neoplasm. Macrophage infiltration was abundant in all tumours with widespread immunoreactivity for Iba-1 and HLA-DR. Most tumours (15/17; 88%) had infiltration by MAC387 + macrophages; however, the number of infiltrating cells per ×400 field varied widely (from 0 to 57). Thirteen of 17 tumours (76%) had infiltration by CD163 + macrophages; however (similar to the MAC387 IHC), several tumours had numerous infiltrating cells. There was a potential weak negative rank correlation between the counts of CD3 and Ki67 + cells (r Sp = −0.57; P = 0.018); however, no other rank correlations could be established between types of infiltrating immune cells (all other P ≥0.10). This study establishes evidence for a robust population of immune cells in feline meningioma and indicates that further study is needed to better understand the role of these cells with respect to tumour progression and post-surgical outcome. [ABSTRACT FROM AUTHOR]

The objective of this study is to determine the rate of toxicity, median survival time (MST) and prognostic factors in dogs with presumed intracranial meningiomas that were treated with stereotactic radiation therapy ( SRT). Patient demographics, neurological history, details of SRT plans and response to treatment (including toxicity and survival times) were examined for potential prognostic factors. Overall MST ( MST) due to death for any cause was 561 days. There was a mild to moderate exacerbation of neurological symptoms 3-16 weeks following SRT treatments in 11/30 (36.7%) of dogs. This presumed adverse event was treated with corticosteroids, and improvement was seen in most of these dogs. Death within 6 months of treatment as a result of worsening neurologic signs was seen in 4/30 (13.3%) of dogs. Volume of normal brain that received full dose at a prescription of 8Gy × 3 fractions was predictive of death due to neurological problems within this 6-month period. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To compare conventional MRI and nonenhanced 3-D time-of-flight (TOF) magnetic resonance angiography (MRA) findings between dogs with meningioma and dogs with intracranial histiocytic sarcoma (IHS). DESIGN: Retrospective case series. ANIMALS: 14 dogs with meningioma and 5 dogs with IHS. PROCEDURES: Medical records of dogs with meningioma or IHS that were examined at a tertiary veterinary hospital from 2010 through 2014 and underwent 3-D TOF MRA in conjunction with conventional MRI were reviewed. Findings for conventional MRI and 3-D TOF MRA were compared between the 2 groups of dogs to evaluate whether there were any characteristics that could be used to differentiate meningioma from IHS. RESULTS: Tumor type was significantly associated with signal intensity on conventional T2- weighted and fluid-attenuated inversion recovery MRI images; most meningiomas were hyperintense.and most IHSs were isointense or hypointense on those images. Tumor type was not associated with signal uniformity, tumor location, tumor origin, or the presence of edema, midline shift, or brain herniation. On MRA, blood vessels adjacent to the tumor were identified and characterized for 9 of 14 dogs with meningioma and all 5 dogs with IHS.Vessels adjacent to meningiomas were displaced in 8 of 9 dogs, whereas vessels adjacent to IHSs were not displaced. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated nonenhanced 3-DTOF MRA findings provided additional information that can be assessed in conjunction with conventional MRI findings to help differentiate meningiomas from IHSs in dogs. [ABSTRACT FROM AUTHOR]

The article describes the case of a 9-year-old female domestic long-haired cat with a history of behavior changes and weight loss, and diagnosed with a cholesterol granuloma formation within a meningioma. The diagnosis was confirmed after performing blood chemistry, physical and neurologic examination, and brain magnetic resonance imaging (MRI). Necropsy of the cat revealed gross lesions that were situated within the falx cerebri at the level of the frontal cortices and corpus callosum.

Context The propagation of meningiomas has been linked with several inflammatory interleukins (ILs). Human meningioma cells have been found to synthesise and secrete IL-6, as well as to express IL-8 mRNA. The aim of this study was to determine whether canine intracranial meningiomas express IL-6 and/or IL-8. Main conclusion The limited IL-6 expression and lack of IL-8 expression indicated that IL-6 and IL-8 inhibitors were unlikely to be beneficial for the treatment of canine meningiomas. The limited IL expression may be because of species differences, fewer high-grade tumours or sample size. Approach Nineteen surgically excised formalin-fixed, paraffin-embedded canine intracranial meningioma biopsy samples were collected. Immunohistochemical detection of IL-6 and IL-8 was performed by an automated staining system using anti-canine IL-6 and anti-canine IL-8 monoclonal antibodies, respectively. To quantify IL-6 and IL-8, staining of the entire meningioma section was evaluated for percentage of cells positively stained and their staining intensity. The percentage of cells positively stained was recorded as: 0 per cent of cells stained; 1 to 30 per cent of cells stained; 31 to 60 per cent of cells stained; and 61 to 100 per cent of cells stained. Staining intensity was subjectively recorded as: 0, negative expression; 1, weak expression; 2, moderate expression; and 3, marked expression. Results Of the 19 tumour samples, staining for IL-6 expression was positive in five samples and IL-8 expression was positive in zero samples. IL-6 staining in the positive tumour samples was seen as diffusely cytoplasmic. In all five IL-6 positively stained samples, the percentage staining area was greater than 61 per cent; two of the five positive samples had weak staining intensity, while the remaining three positive samples had moderate staining intensity. Interpretation The limited IL-6 expression and lack of IL-8 expression indicates that IL-6 and IL-8 inhibitors are unlikely to be beneficial for the treatment of canine meningiomas. However, it should be noted that a failure to detect an antigen with immunohistochemistry may not be equivalent to a lack of expression. Significance of findings This study showed that the role of ILs in the pathophysiology of canine intracranial meningiomas seems to be limited. [ABSTRACT FROM AUTHOR]

Objective--To describe findings of 3.0-T multivoxel proton magnetic resonance spectroscopy (¹H-MRS) in dogs with inflammatory and neoplastic intracranial disease and to determine the applicability of ¹H-MRS for differentiating between inflammatory and neoplastic lesions and between meningiomas and gliomas. Animals--33 dogs with intracranial disease (19 neoplastic [10 meningioma, 7 glioma, and 2 other] and 14 inflammatory). Procedures--3.0-T multivoxel ¹H-MRS was performed on neoplastic or inflammatory intracranial lesions identified with conventional MRI. N-acetylaspartate (NAA), choline, and creatine concentrations were obtained retrospectively, and metabolite ratios were calculated. Values were compared for metabolites separately, between lesion categories (neoplastic or inflammatory), and between neoplastic lesion types (meningioma or glioma) by means of discriminant analysis and 1-way ANOVA. Results--The NAA-to-choline ratio was 82.7% (62/75) accurate for differentiating neoplastic from inflammatory intracranial lesions. Adding the NAA-to-creatine ratio or choline-to-creatine ratio did not affect the accuracy of differentiation. Neoplastic lesions had lower NAA concentrations and higher choline concentrations than inflammatory lesions, resulting in a lower NAA-to-choline ratio, lower NAA-to-creatine ratio, and higher choline-to-creatine ratio for neoplasia relative to inflammation. No significant metabolite differences between meningiomas and gliomas were detected. Conclusions and Clinical Relevance--¹H-MRS was effective for differentiating inflammatory lesions from neoplastic lesions. Metabolite alterations for ¹H-MRS in neoplasia and inflammation in dogs were similar to changes described for humans. Use of ¹H-MRS provided no additional information for differentiating between meningiomas and gliomas. Proton MRS may be a beneficial adjunct to conventional MRI in patients with high clinical suspicion of inflammatory or neoplastic intracranial lesions. [ABSTRACT FROM AUTHOR]

Cutaneous meningiomas are rare tumors in human beings and animals. Two canine cases of cutaneous meningiomas affecting the eyelid are described in the current study: the first from a 5-week-old female Springer Spaniel dog with an 8 cm in diameter congenital mass expanding the left upper eyelid and medial canthus; the second from a 10-year-old female spayed Maltese–Poodle mix dog with 3 firm subcutaneous nodules affecting the right upper eyelid. All masses were removed surgically. Histologically, tumors were composed of spindle-to-epithelioid cells arranged in small lobules forming solid concentric whorls. Neoplastic cells were positive for vimentin and S100 and negative for pancytokeratin, glial fibrillar acid protein, and neurofilament. Transmission electron microscopy revealed meningothelial cells with convoluted interdigitating processes, desmosomes, and hemidesmosomes, and moderate numbers of cytoplasmic microfilaments. None of the cases presented a primary neuroaxial meningioma. The first case presents clinicopathological features consistent with human type I (congenital) cutaneous meningioma. The second case is consistent with a type II (acquired ectopic) tumor, and both are hypothesized to arise from ectopic arachnoid cells displaced during development. [ABSTRACT FROM PUBLISHER]

The article presents a case study of a 10-year-old neutered female boxer dog diagnosed with vacuolar meningioma. It notes that the boxer dog's neurological evaluation shows hypermetria and ataxia in her four limbs. It points out the success of her therapies including durotomy, marsupialisation and suboccipital craniectomy. It also mentions her recovery from surgery.

Matrix metalloproteinases (MMPs) are proteolytic enzymes involved with extracellular matrix degradation. They have been considered to be important for tumor growth and development of peritumoral edema. This retrospective study investigated the expression of MMP subtypes 9 and 2 in canine intracranial meningiomas and their association with peritumoral edema. Twenty-two cases of histologically confirmed grade I meningiomas based on human World Health Organization classification were enrolled. Tumor volume and peritumoral edema were measured by magnetic resonance imaging volumetry. The intratumoral MMP expression was semiquantitatively assessed by immunoreactivity scores and compared with the imaging data. MMP-9 was expressed in all the samples (22/22), whereas proMMP-2 was expressed in 21 of 22 meningiomas, and a/proMMP-2 was expressed in 9 of 22. The immunoreactivity scores were not statistically linked to the severity of peritumoral edema. None of the evaluated MMP expression parameters were statistically linked to the edema index. Although both edema index and MMP-9 expression were highest in meningiomas of the olfactory and frontal region, only the latter mounted up to statistical significance (P = .002) if compared with parafalx and convexity meningiomas of the parietal lobe. In summary, MMP-2 and MMP-9 expression by tumor cells, evaluated through immunohistochemistry, is not predictive of the formation of peritumoral edema in canine rostrotentorial meningiomas. [ABSTRACT FROM PUBLISHER]

The article presents the clinical and histological features of 8 spinal meningiomas in dogs. Clinical signs, neurological examinations, clinicopathological statistics and surgery reports were analyzed. Two dogs showed signs of lateralization including hemiparesis and propioceptive deficits in limbs and spinal pain was present in five dogs.

Summary: Several subtypes of canine meningioma are recognized. This report describes four canine meningiomas with previously unreported features. The four affected dogs were of different breeds. Three of the affected dogs were male and aged 7–10 years. In one dog, age and gender were not recorded. Meningiomas were located intracranially (three dogs) or within the vertebral canal (one dog). Two meningiomas resembled gemistocytic astrocytomas, while one had focal features of a rhabdoid tumour; these three meningiomas also contained amyloid deposits. The fourth tumour, a secretory meningioma, was rich in amianthoid fibres (i.e. unusual collagen deposits containing giant collagen fibres). All of these features are also described in human meningiomas. [ABSTRACT FROM AUTHOR]

Meningiomas are the most common intracranial tumors in dogs. A variety of inflammatory cells have been shown to invade these tumors in people, but little is known about interactions between the immune system and naturally occurring brain tumors in dogs. The purpose of this study was to investigate the presence of a variety of immune cell subsets within canine intracranial meningiomas. Twenty-three formalin-fixed, paraffin-embedded tumor samples were evaluated using immunohistochemistry with antibodies specific for CD3, CD79a, CD18, CD11d (αD), CD45RA, forkhead box P3, and Toll-like receptors 4 and 9. Immune cell infiltration was evident in all samples, with a predominance of CD3+ T cells. Large numbers of CD18+ microglia and macrophages were noted surrounding and infiltrating the tumors, and a subset of these cells within the tumor appeared to be CD11d+. Scattered macrophages at the tumor–brain interface were TLR4+ and TLR9+. Rare CD79a+ B cells were noted in only a small subset of tumors. Lesser numbers of lymphocytes that were CD11d+, CD45RA+, or FoxP3+ were noted in a number of the meningiomas. Although the function of these cells is not yet clear, work in other species suggests that evaluation of this immune cell infiltrate may provide important prognostic information and may be useful in the design of novel therapies. [ABSTRACT FROM PUBLISHER]

The article presents a case study of an 11-year-old female shepherd mix dog presented for seizures for 12 days. It says that the patient underwent several tests such as magnetic resonance imaging (MRI), cranial nerve examination and neurological tests. It says that the dog was diagnosed with multiple meningiomas. It states that craniotomy was conducted for the removal of intracranial masses.

Meningiomas are the most common primary brain tumours in dogs and cats. There are several morphological phenotypes of this extra-axial neoplasm and they show predilections for certain anatomical locations. There have been a number of attempts to apply the current World Health Organization (WHO) classification for human meningiomas to dogs and cats and to obtain a universal classification scheme for domestic animals. Recently, certain enzymes involved in tumour growth have been recognised as biological markers and have been related to degrees of malignancy. The secondary effects of meningiomas have also been investigated, and vascular endothelial growth factor and peritumoural oedema have been reported to reduce survival rate. Breed and age predisposition are recognised in both dogs and cats and the presenting clinical signs are quite consistent. Magnetic resonance imaging and computed tomography are the techniques of choice for the presumptive diagnosis of meningiomas in domestic animals but advanced imaging techniques are constantly being developed and applied. Treatment methods for meningiomas involve a combination of de-bulking surgery, chemotherapy and radiotherapy, and detailed accounts of several treatment protocols have been reported. [ABSTRACT FROM AUTHOR]

Objective To describe a case of intracranial meningioma causing visual impairment in a cat, successfully treated by surgery. Procedures An adult neutered male domestic cat was referred with a 10-month history of progressive visual impairment and altered behavior. Investigations included physical, ophthalmologic and neurological examinations as well as hematology, serum biochemistry and CT scan of the head. Results The menace response was absent in the left eye and decreased in the right eye. Electroretinograms were normal on both eyes, as was ophthalmic examination, ruling out an ocular cause and allowing a presumptive diagnosis of partial amaurosis due to a post-retinal lesion. CT scan demonstrated a large sessile extra axial mass along the right parietal bone and thickening of the adjacent bone. Cerebrospinal fluid was not collected because high intracranial pressure represented a risk for brain herniation. A right rostrotentorial craniectomy was performed to remove the tumor. Ten days after surgery, vision was improved, neurological examination was normal and normal behavior was restored. Ten months after surgery, ophthalmological examination showed no visual deficit and CT scan did not reveal any sign of recurrence. Conclusion Advanced imaging techniques allow veterinarians to detect early cerebral diseases and to provide specific treatment when it is possible. In cases of feline amaurosis due to intracranial meningioma, the vital prognosis is good while the visual prognosis is more uncertain, but recovery of normal vision and normal behavior is possible as demonstrated in the present case. [ABSTRACT FROM AUTHOR]

The article evaluates an 11-year-old Fox Terrier dog for a history of progressive exophthalmia and visual deficits in the right eye. The dog is suffering from a severe corneal fibrosis and pigmentation. Upon further examination, findings showed that the dog also has an absent menace response bilaterally.

The article presents a study on the treatment of seven dogs with frontal lobe meningiomas through surgery and radiation therapy. It mentions that five dogs were operated through bilateral transfrontal sinus, and one dog was euthanized after surgery. It states that the surgery combined with radiation therapy has allowed a survival rate for meningiomas of the frontal lobe similar to meningiomas over the cerebral convexities.

The article presents a case study of a female cross-breed dog with microcystic meningioma of the fourth ventricle. The dog presented with progressive changes in the head posture and gait. A central vestibular syndrome lateralized to the left was identified through neurological examination. A lesion within the fourth ventricle was detected through magnetic resonance imaging (MRI). Neoplastic cells were found to react positively with vimentin and negatively with glial fibrillary acidic protein (GFAP) and factor VIII-related antigen (FVIII).

Neoplasms of the nervous system, whether spontaneous or induced, are infrequent in laboratory rodents and very rare in other laboratory animal species. The morphology of neural tumors depends on the intrinsic functions and properties of the cell type, the interactions between the neoplasm and surrounding normal tissue, and regressive changes. The incidence of neural neoplasms varies with sex, location, and age of tumor onset. Although the onset of spontaneous tumor development cannot be established in routine oncogenicity studies, calculations using the time of diagnosis (day of death) have revealed significant differences in tumor biology among different rat strains. In the central nervous system, granular cell tumors (a meningioma variant), followed by glial tumors, are the most common neoplasms in rats, whereas glial cell tumors are observed most frequently in mice. Central nervous system tumors usually affect the brain rather than the spinal cord. Other than adrenal gland pheochromocytomas, the most common neoplasms of the peripheral nervous system are schwannomas. Neural tumors may develop in the central nervous system and peripheral nervous system from other cell lineages (including extraneural elements like adipose tissue and lymphocytes), but such lesions are very rare in laboratory animals. [ABSTRACT FROM PUBLISHER]

A 23-month-old castrated male Cavalier King Charles spaniel was evaluated because of a 6-month history of unusual rippling/undulating movements of the right facial muscles that were continuous and persisted during sleep. Neurological examination revealed narrowing of the right palpebral fissure and unilateral right-sided facial myokymia that was characterised by myokymic, and to a lesser degree, neuromyotonic discharges on concentric needle electromyographic examination. After persisting unchanged for almost 2.5 years from its onset, the facial myokymia gradually disappeared over a 6-month period concomitant with the emergence of a persistent ipsilateral facial paralysis and head tilt. At 5 years and 9 months after the first examination, signs of ipsilateral lacrimal, pharyngeal and laryngeal dysfunction became evident and the dog was euthanased. Postmortem examination identified a malignant (WHO grade III) meningioma in the right cerebellopontomedullary angle that compressed the ventrolateral cranial medulla, effaced the jugular foramen and internal acoustic meatus and extended into the facial canal of the petrous temporal bone. Novel findings were the unique observation of isolated unilateral facial myokymia preceding diagnosis of a meningioma affecting facial nerve function within the caudal cranial fossa and the remarkably long duration of neurological signs (75 months) attributable to the neoplasm. [ABSTRACT FROM AUTHOR]

The article presents a study which examined immunohistochemical detection of meningiomas in cats and dogs which include tumor types as angiomatoid, fibroblastic and microcystic. It states that the immunoreactivity for CD34, claudin-1 and E-cadherin were present in most tumors. Antibody reagents and detection systems used in immunohistochemistry are explained.

A 9-year-old, spayed female Chihuahua was presented for evaluation of acute, progressive neurologic disease. On physical examination the dog was depressed and laterally recumbent. The dog had marked neutrophilia with a toxic left shift and monocytosis. Using computed tomography with contrast enhancement a large intracranial mass lesion was identified in the rostral portion of the brain. The mass extended from the central thalamic region rostral to the cribiform plate and obliterated the lateral ventricles. A fine needle aspirate of the mass contained moderately pleomorphic polygonal cells with many intranuclear cytoplasmic pseudoinclusions (ICPs). The primary differential diagnosis was meningioma, based on cell morphology and the presence of ICPs. At necropsy, the mass was well-demarcated, unencapsulated, and densely cellular. Cells were arranged in papillary projections on fibrovascular stalks, and eosinophilic ICPs and nuclear folding were frequently seen. Cavitated areas of necrosis throughout the tumor mass were filled with intact and degenerated neutrophils. The histopathologic diagnosis was malignant papillary meningioma. ICPs are not frequently observed in Wright-stained cytologic preparations but may be found in many types of neoplasms, including meningiomas. [ABSTRACT FROM AUTHOR]

The article presents a study that investigates the immunohistochemical expression of matrix metalloproteneise (MMP)-2 and MMP-9. Meningiomas obtained from dogs and cats were used to compare to the reverse transcriptase subunit of human-telomerase, progesterone receptor, proliferative index of tumors and cellular nuclear antigen. The study finds no significant correletion with between the MMP, niether its correlation with dogs and human. However, MMP-2 and MMP-9 was present in cats.

An 11-year-old neutered female domestic shorthair indoor cat was presented to our hospital for treatment of a left-sided rostro-temporal basal meningioma. Focal seizures in the facial muscles had been observed sporadically for 1 year. Two weeks prior to presentation the cat had developed generalised seizures and was treated with symptomatic anticonvulsive treatment. Focal facial seizures, especially on the right side, persisted after medical therapy. From the computed tomography scan, a basal meningioma was suspected by the treating veterinarian. A left-sided suprazygomatical temporobasal approach to the zygomatic arch was chosen because it causes less soft tissue damage. After craniotomy, durotomy and gentle dorsal retraction of the left piriform lobe, the meningioma was removed. Postoperative magnetic resonance imaging confirmed complete excision of the tumour. One day after surgery the cat was alert and a left-sided facial nerve palsy was noticed. Otherwise the neurological examination was normal. Anticonvulsive and eye moistening therapy was continued for 3 months. Six months after surgery the cat was clinically normal without any recurrence of seizures. [Copyright &y& Elsevier]

Primary brain tumours were identified in two Bactrian camels (Camelus bactrianus) living at the Zoological Society of London's two zoos. Histology and immunohistochemistry were used to diagnose a histiocytic sarcoma in a 16-year-old female and a fibroblastic meningloma In a 13-year-old male. Before one died and the other was euthanased both camels had shown progressive neurological signs, includIng circling and ataxia. [ABSTRACT FROM AUTHOR]

Background: The benefits of endoscopic assistance to remove intracranial tumors in small animals are not described. Objective: To evaluate the effectiveness of endoscopic-assisted intracranial tumor removal in dogs and cats. Animals: Thirty-three dogs and 6 cats with intracranial tumors. Methods: Retrospective study. CBC, serum chemistry profile, coagulation testing, blood typing, and systemic tumor staging, which included 3-view thoracic radiographs and abdominal ultrasound examination, were performed to detect other significant underlying disease in preparation of the animal for surgery. Magnetic resonance imaging was used in 37/39 cases to image the brain tumor. Surgical approach was dictated by the location of the tumor. Histopathologic examination of the tumor tissue was performed in all cases. Animals were followed throughout their postoperative course for complications and survival times. Statistical analysis (Kaplan-Meier curves) was performed to obtain median survival times in dogs with meningiomas. Results: Use of an endoscope resulted in visualization of residual tumor and potentially more complete removal of the brain tumors. There were no clinically important complications associated with the use of the endoscope. Median survival time was 2,104 days for dogs with forebrain meningiomas surgically removed with endoscopic assistance and 702 days for dogs with caudal brain meningiomas. Conclusions and Clinical Importance: These results demonstrate that the use of an endoscope to assist in brain tumor removal is apparently safe and might result in improved survival times. [ABSTRACT FROM AUTHOR]

Background: Tumor proliferation in human intracranial meningiomas can be defined by the reactivity of the monoclonal antibody MIB-1 to the Ki-67 antigen. Vascular endothelial growth factor (VEGF), a pro-angiogenic factor, is a predictive marker for survival of dogs with intracranial meningiomas. Hypothesis: Ki-67 is expressed in canine intracranial meningiomas and is associated with VEGF expression. Ki-67 expression is a prognostic marker for patient outcome. Animals: Seventy client-owned dogs with WHO grade I intracranial meningiomas. Methods: Retrospective study assessing the degree of immunostaining for Ki-67 by MIB-1 and VEGF expression in intracranial meningioma tissue from dogs. MIB-1 Labeling Index (LI) was calculated with Image J NIH-software. Extent, intensity, and distribution of VEGF-expression was assessed semiquantitatively. Cross tabulations with Fisher's exact tests and nonparametric Spearman's rank correlations were performed to identify associations between VEGF expression and MIB-1 LI. Fifteen dogs underwent postsurgical radiotherapy and were included in survival analysis. The effect of MIB-1 LI on survival was examined by Kaplan-Meier and Cox proportional hazards regression procedures. Results: Ki-67 staining was positive in 91% (64/70) and VEGF expression was detected in 96% (67/70). There was no significant association between VEGF expression and MIB-1 LI. MIB-1 LI was not associated with survival. Conclusions and Clinical Importance: MIB-1 antibody can be used to document cell proliferation in intracranial meningiomas in dogs, but does not predict outcome. No association between VEGF as a marker of angiogenesis and tumor proliferation was found. Angiogenesis might be a more important predictor of meningioma activity in dogs than is Ki-67. [ABSTRACT FROM AUTHOR]

Objective--To quantitatively evaluate expression of vascular endothelial growth factor (VEGF) in intracranial tumors in dogs and determine whether relationships exist between circulating and intratumoral VEGF concentrations and tumor type and grade. Animals--27 dogs with primary intracranial neoplasms and 4 unaffected control dogs. Procedures--Plasma and brain tumor samples were obtained from each dog, and plasma and intratumoral concentrations of VEGF were measured by use of an ELISA. Results--Dogs with meningiomas (n = 11) were significantly older than dogs with oligodendrogliomas (7) or astrocytomas (9). Measurable VEGF was detected in all tumors, and a significant negative correlation between age and intratumoral VEGF concentration was detected. Age-adjusted comparisons identified significant differences in intratumoral VEGF concentratiohs among all tumor types; the highest VEGF concentrations were associated with astrocytomas. Within each tumor type, increasing tumor grade was significantly associated with increasing VEGF expression. Plasma VEGF concentrations were detectable in 9 of 27 dogs; the proportion of dogs with astrocytomas and a detectable circulating VEGF concentration (7/9 dogs) was significantly higher than the proportion of dogs with meningiomas (1/11 dogs) or oligodendrogliomas (1/7 dogs) with a detectable circulating VEGF concehtration. Conclusions and Clinical Relevance--Overexpression of VEGF appears common in canine astrocytomas, oligodendrogliomas, and meningiomas. In the neoplasms examined, intratumoral VEGF concentrations correlated well with tumor malignancy. The VEGF expression patterns paralleled those of analogous human tumors, providing evidence that dogs are a suitable species in which to study angiogenesis and intracranial neoplasia for human application. [ABSTRACT FROM AUTHOR]

The cyclin-dependent kinase (CDK) inhibitor p16INK4a and the MDM2 ubiquitin ligase inhibitor p19ARF are critical to the regulation of cell cycle progression. Their loss by deletion, mutation or epigenetic silencing is a common molecular alteration in many human cancers. To investigate the role of p16INK4a/p19ARF deficiency in CNS tumor pathogenesis, pregnant mice bearing p16-/-/p19-/-, p16+/-/p19+/-, and p16+/+/p19+/+ embryos were exposed transplacentally on gestation day 14 to a single dose of the potent carcinogen, ethylnitrosourea (ENU). p16+/-/p19+/- male mice treated with ENU developed meningial proliferative lesions with a high incidence (5/10). The incidence was lower in other ENU-treated animals of both sexes and none occurred in saline-treated control animals. The lesions ranged from widespread meningeal proliferation and plaque-like thickening by neoplastic spindle cells consistent with meningiomatosis to a larger discrete mass consistent with a meningioma. Ultrastructural analysis revealed the presence of intercellular junctions between cells, supporting a meningothelial histogenesis. Spontaneous meningiomas occur rarely in wild-type mice but are a common neoplasm afflicting humans, accounting for between 13 and 26% of primary intracranial neoplasms. This ENU inducible meningeal lesion in p16+/-/p19+/- mice may provide additional insight into the pathogenesis of meningeal neoplasia and aid the development of therapeutics. [ABSTRACT FROM AUTHOR]

A 13-year-old male neutered Persian crossbred cat was evaluated for hindlimb paresis, ataxia and urinary incontinence that had been progressing over the previous 3 months. Neurologically, the cat had thoracolumbar spinal cord deficits and a myelogram detected the presence of a mass compressing the thoracic spinal cord. A hemilaminectomy was performed to excise the soft tissue mass, subsequently identified histologically as a psammomatous meningioma. The cat regained ambulatory function and continence following surgery until a recurrence of paresis and ataxia 36 months later. A second myelogram suggested local recurrence of the tumour, which was confirmed by histological examination of the tumour after its removal at a second laminectomy. The cat again regained normal neurological function, until a further recurrence 16 months after the second surgery. The meningioma was surgically debulked a third time and the cat regained ambulation and continence postoperatively. This case demonstrates the successful use of repeated surgical resection in the management of a recurrent spinal meningioma in a cat. The cat was ambulatory and continent at a follow-up examination 63 months after the initial presentation. [ABSTRACT FROM AUTHOR]

Telomere length maintenance is regarded as a fundamental step in tumorigenesis, as most human brain tumors, including meningiomas, stabilize the ends of their chromosomes using telomerase. This investigation represents an introduction to telomerase expression in canine and feline meningiomas. Twenty-five archived cases (14 dogs and 11 cats) were immunohistochemically tested for human-telomerase reverse transcriptase (h- TERT), scored, and quantified; furthermore, mitoses were counted on sections stained with a modified toluidine blue. The h-TERT antibody immunolabelled the nucleus and nucleolus of meningeal neoplastic cells, with an intensity ranging from mild to strong and a speckled distribution; a significantly higher expression in cats was noted, while no significant association between h-TERT immunolabelling and sex or histotype was evident in dogs or cats. The telomerase enzyme represents a fundamental parameter of potential malignant transformation, which may occur independently of the signal to proliferate, thereby supplying the cells with unlimited growth capabilities. Telomerase expression could be a prognostic indicator independent of the kinetic parameters, although this should be evaluated using a larger dataset with available clinical information. [ABSTRACT FROM AUTHOR]

Summary: A wild common dolphin was found stranded on the French Atlantic coast. At necropsy, an intracranial grey- to tan-coloured mass (7 × 5 × 4cm) was found at the right cerebellopontine angle, compressing the right cerebellar hemisphere, the brainstem and the occipital lobe of the right cerebral hemisphere. Microscopically, the tumour was composed of small lobules of polygonal to elongated neoplastic cells with multifocal areas of stellate and vacuolated cells. Neoplastic cells strongly expressed vimentin, S-100 protein and neuron-specific enolase. They were rarely positive for cytokeratin. Ultrastructurally, the neoplastic cells displayed all the diagnostic features of meningiomas and in some areas showed long cytoplasmic processes delimiting extracellular spaces. The immunohistochemical and ultrastructural features were consistent with the histopathological diagnosis of a microcystic meningioma. This is the first report of a meningioma in dolphins or in any other cetacean species. [Copyright &y& Elsevier]

Objective—To determine results of intracranial meningioma resection by use of a surgical aspirator and assess prognostic factors associated with intracranial meningiomas in dogs. Design—Retrospective case series. Animals—17 dogs. Procedures—Medical records of dogs that under-went resection of an intracranial meningioma by use of a surgical aspirator were reviewed. Information pertaining to signalment, imaging findings, clinical signs, duration of clinical signs, preoperative treatment, location of the tumor, results of histologic assessment, outcome, and necropsy results was obtained from the medical record. Clients and referring veterinarians were contacted via telephone for information on recurrence of clinical signs and postoperative survival time. Results—16 dogs were > 7 years of age, and all 17 dogs had seizures before surgery. The most commonly affected breed was the Golden Retriever, represented by 6 of the 17 dogs. Median survival time was 1,254 days. Of the data collected, only histologic subtype of the tumor was prognostic. Analysis of survival times according to histologic tumor subtypes indicated that the order from most brief to longest was as follows: anaplastic, 0 days; fibroblastic, 10 days; psammomatous, > 313 days; meningothelial, > 523 days; and transitional, 1,254 days. Conclusions and Clinical Relevance—Use of a surgical aspirator to resect intracranial meningiomas in dogs was associated with longer survival times than those achieved with traditional surgery alone or traditional surgery combined with radiation therapy. Dogs with meningothelial, psammomatous, or transitional intracranial meningioma subtypes appeared to have a better prognosis than dogs with other subtypes of meningioma. [ABSTRACT FROM AUTHOR]

Objective--To validate mutual information criterion as a ready-to-use technique for automated alignment (ie, registration) of 3-dimensional (3-D) multimodal image data of the head of cats and dogs. Sample Population--Corresponding 3-D magnetic resonance imaging (MRI) and computed tomography (CT) brain scans of a 6-month-old Doberman Pinscher with a brain cyst; CT images of the head of a European shorthair cat with a meningioma before and immediately, 3, and 6 months after surgical resection; and CT and corresponding stacked anatomic cryosection images of the entire head of a 2-year-old sexually intact female Beagle. Procedure--All images were matched retrospectively by use of an in-house computer program developed on the basis of a mutual information image registration algorithm. Accuracy of the resulting registrations was evaluated by visual inspection. Results--All registrations were judged to be highly accurate. Additional manual corrections were not necessary. Conclusions and Clinical Relevance--Mutual information registration criterion can by applied to 3-D multimodal head images of cats and dogs for full automatic rigid-body image registration. The combination of such aligned images would considerably facilitate efforts of veterinary clinicians as indicated by its widespread use in brain surgery and radiation therapy of humans. (Am J Vet Res 2004;65:1680-1687). [ABSTRACT FROM AUTHOR]

Objective--To evaluate progesterone and estrogen receptor expression in meningiomas of the CNS in dogs and cats. Animals--8 dogs (1 of which was treated with gestrinone) and 5 cats with intracranial meningiomas and 2 dogs with spinal cord meningiomas; tissue samples were also obtained from 1 clinically normal dog and 1 clinically normal cat. Procedure--Meningioma tissue was obtained during surgery or at necropsy; samples were processed for histologic classification and immunohistochemical evaluation of the proportion of tumor cells with progesterone and estrogen receptors. Correlation among receptor expression, tumor grade, and histologic subtypes was determined. Results--Several histologic subtypes of intracranial meningiomas were detected among tissue samples. In the cats, all intracranial meningiomas were benign. Progesterone receptor immunoreactivity was detected in 14 of 15 meningiomas. Progesterone receptor expression was identified in > 80% of cells in 8 intracranial meningiomas (4 dogs and 4 cats) and 2 spinal cord meningiomas. In samples of malignant transitional and granular cell meningiomas in dogs, progesterone receptors were detected in 32 and 4.8% of cells respectively. In 1 cat, 38% of tumor cells had progesterone receptors. In a dog treated with gestrinone, no progesterone receptors were detected in the intracranial meningioma. Estrogen receptors were only detected in the tumor of 1 dog. Conclusions and Clinical Relevance--Results indicate a high proportion of progesterone receptors in cells of meningiomas of the CNS in dogs and cats. Antiprogesterone treatment may have a role in the treatment of unresectable or recurrent meningiomas in dogs and cats. [ABSTRACT FROM AUTHOR]

Clinical and pathologic features of primary orbital meningiomas in the dog were reviewed. Twenty-two meningiomas, confined to the orbit, were identified from the Comparative Ophthalmic Pathology Laboratory of Wisconsin from 1981 to 1997. The dogs ranged in age from 3 to 17 years (mean = 9.2 years). The clinical presentation, reported in 20 cases, was indicative of a retrobulbar mass and included exophthalmos and orbital swelling (18/20), and papilledema or abnormalities of the posterior segment (7/20). Visual acuity was reported in 15 cases; of those, 12 dogs were blind in the affected eye. Follow-up information was obtained on 17 cases; six dogs developed local recurrence of the neoplasm. Two dogs with recurrent neoplasms simultaneously developed blindness in the opposite eye. Extension along the optic nerve to the optic chiasm was suspected. No metastasis was found at the time of the study. Enucleation with excisional biopsy was effective therapy to date in 11 cases (0.2–4.5 years follow-up time). All neoplasms were located within the vicinity of the optic nerve and, when sectioned through the optic nerve head, appeared to completely envelope the nerve. The neoplastic cells were arranged in tight whorls and bundles characteristic of meningiomas. Most tumors had islands of chondroid and osseous metaplasia (17/22). Ocular invasion was limited to small foci in the posterior choroid or optic nerve head of six dogs. Immunoperoxidase stains on 10 cases were positive for vimentin and S-100, but negative for cytokeratin. Electron microscopy revealed complex interdigitations between cell membranes and few desmosomal intercellular attachments. Primary orbital meningiomas have a characteristic histologic appearance and may recur locally after surgical excision. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the different in histological presentations of meningiomas and their immunohistochemical panel in dogs evaluated between 2010 and 2012. It were evaluated the clinical data, localization, histological classification and immunohistochemical characterization. Their mean age was 10 years. Five animals were male and one female. Tumors were located primarily in the thoracic spinal cord. The most frequent histological types were meningothelial and transitional. All meningiomas were positive for vimentin. [ABSTRACT FROM AUTHOR]

The article presents a case study of a four-year old male labrador retriever which was diagnosed with seizures. The dog began to experience involuntary masticatory movements after its veterinarian prescribed a dose of phenobarbital. According to clinical examinations, the dog was diagnosed to have a focal lesion found in the left portion of the brainstem. Computed tomography scanning was conducted which revealed the existence of intracranial neoplasia such as granulomatous meningoencephalitis.

Discusses the clinical, magnetic resonance imaging and pathological findings of concurrent benign and malignant multiple meningiomas in a cat. Clinical signs associated with solitary large, extra-axial meningioma; Use of survey radiography in the clinical diagnosis of meningioma.

A letter to the editor is presented in response to the article "Cytologic appearance of retinal cells included in a fine-needle aspirate of a meningioma around the optic nerve of a dog."

Describes a case of extracranial meningioma in a dairy cow. Clinical characteristics of meningiomas; Performance of computed tomography (CT) and magnetic resonance imaging (MRI) before gross dissection in the cow's head; Consideration of CT and MRI examination as options for gross observation of a tumor in situ before dissection.