brain tumors
Some symptoms for brain tumors are seizures, signs of pain, change in gait, mental ability diminished, trouble breathing. With brain tumors they may lose their sense of smell, sight, or hearing. With brain tumors they may either lose their appetite or the opposite, become ravenous. They may no longer be house trained.
gliomas are more prevalent in short muzzled(bradycephalic), dome skulled breeds like chihuahuas, pugs, pekingese,labs, golden retrievers, Boston terriers and boxers. It is not clear if there is a hereditary link. Meningiomas occur more frequently in male cats than in female cats. Meningiomas and gliomas are the most common of the brain tumors. Brain tumors are usually found in dogs over five years old. Magnetic resonance imaging (MRI) is the primary tool for diagnosis. Surgery, radiation/and/or chemotherapy is the treatment.
Am J Vet Res. 2004 Dec;65(12):1680-7. : Automatic image registration of three-dimensional images of the head of cats and dogs by use of maximization of mutual information.
Bottcher P, Maierl J, Hecht S, Matis U, Liebich HG.
Department of Small Animal Surgery, Faculty of Veterinary Medicine, Ludwig-Maximilians-University, Munich, Germany.

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.
J Vet Med A Physiol Pathol Clin Med. 2004 Jun;51(5):226-31. : Diagnostic correlation of CT-MRI and histopathology in 10 dogs with brain neoplasms.
Polizopoulou ZS, Koutinas AF, Souftas VD, Kaldrymidou E, Kazakos G, Papadopoulos G.
Laboratory of Clinical Diagnosis and Clinical Pathology, School of Veterinary Medicine, Aristotle University of Thessaloniki, Stavrou Voutyra 11, 546 27 Thessaloniki, Greece.
poliz@vet.auth.gr

Ten dogs with primary (n = 8) and metastatic (n = 2) brain tumours were studied in an attempt to evaluate the diagnostic sensitivity of computed tomography (CT) or magnetic resonance imaging (MRI). Of the clinical signs noticed, seizures (seven of 10), behavioural abnormalities and cognition dysfunction (seven of 10), compulsive walking and circling (six of 10), sensorimotor (five of 10) and neuro-opthalmological (two of 10) dysfunction were the most common. In all 10 animals that finally died of the disease or were killed, the histopathological diagnosis that followed necropsy was taken as a golden standard in the CT or MRI prediction of the histological type of brain neoplasms. In every instance, tumour detection, morphology and histological differentiation were possible with the aid of either CT (seven of 10) or MRI (three of 10) imaging especially after contrast enhancement. Only one CT-evaluated dog, diagnosed as meningioma, was found to be astrocytoma on histopathology. Interestingly, a rare case of cerebellar medulloblastoma was correctly identified in MRI scans. Copyright 2004 Blackwell Verlag
Vet Pathol. 2004 Jan;41(1):10-9. : Morphology, immunohistochemistry, and genetic alterations in dog astrocytomas.
Stoica G, Kim HT, Hall DG, Coates JR.
Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4467, USA.
gstoica@cvm.tamu.edu

Astrocytoma is one of the most common tumors of the central nervous system in animals. Of the domesticated animal species, most examples are seen in dogs, and the spectrum that has been described is quiet broad. Previous studies have revealed morphologic similarities between human and animal astrocytomas. Human astrocytomas are often associated with genetic alterations that determine the clinical behavior and therapy outcome. The purpose of this study was to further characterize astrocytomas in dogs and to determine whether there are genetic changes similar to those in the human counterpart.
Vet Radiol Ultrasound. 2004 Jan-Feb;45(1):17-22.: Magnetic resonance imaging findings of an intracranial medulloblastoma in a Polish Lowland Sheepdog.
McConnell JF, Platt S, Smith KC.
Animal Health Trust, Newmarket, Centre for Small Animal Studies, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK.

Medullobastoma is an uncommon caudal fossa tumor. The imaging features of medullobastoma in the dog are poorly described. In this report, the magnetic resonance (MR) appearance of a cerebellar medullobastoma in a dog is described. The MR features were similar to medulloblastomas in adult humans, with the tumor arising laterally and extending to the surface of the cerebellar hemisphere. Correct localization of medulloblastoma may be difficult and it should be considered as a differential for both extra- and intra-axial caudal fossa masses.
1: Vet Pathol. 2003 Nov;40(6):659-69. : Glioblastoma multiforme: clinical findings, magnetic resonance imaging, and pathology in five dogs.
Lipsitz D, Higgins RJ, Kortz GD, Dickinson PJ, Bollen AW, Naydan DK, LeCouteur RA.
Department of Surgical and Radiological sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, USA.

Although glioblastoma multiforme (GBM), a World Health Organization grade IV astrocytoma, is the most common primary brain tumor in humans, in dogs GBM is relatively rare, accounting for only about 5% of all astrocytomas. This study presents combined clinical, neuroimaging, and neuropathologic findings in five dogs with GBM. The five dogs, aged from 5 to 12 years, were presented with progressive neurologic deficits that subsequent clinical neurologic examination and neuroimaging studies by magnetic resonance imaging (MRI), localized to space occupying lesions in the brain. MRI features of the tumors included consistent peritumoral edema (n = 5), sharp borders (n = 4), ring enhancement (n = 3), heterogenous T2-weighted signal intensity (n = 3), iso- to hypointense T1-weighted images (n = 5), necrosis (n = 5), and cyst formation (n = 2). Two tumors were diagnosed clinically using a computed tomography-guided stereotactic biopsy procedure. At necropsy all the tumors resulted in, on transverse sections, a prominent midline shift and had a variegated appearance due to intratumoral necrosis and hemorrhage. Histologically, they had serpentine necrosis with glial cell pseudopalisading and microvascular proliferation, features which distinguish human GBM from grade III astrocytomas. Immunoreactivity of tumor cells for glial fibrillary acidic protein was strongly positive in all cases, whereas 60% and 40% of the tumors also expressed epidermal growth factor receptor and vascular endothelial growth factor, respectively. These canine GBMs shared many diagnostic neuroimaging, gross, microcopic, and immunoreactivity features similar to those of human GBMs.
Vet Pathol. 2003 Sep;40(5):567-9. : An anaplastic astrocytoma (optic chiasmatic-hypothalamic glioma) in a dog.
Siso S, Lorenzo V, Ferrer I, Villagrassa M, Pumarola M.
Department of Animal Medicine and Surgery, Veterinary Faculty, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.

A tumor located in the optic nerve extended through the optic chiasm, involving the hypophysis and the hypothalamic area in a 3.5-year-old male Boxer dog. It showed a biphasic pattern in which numerous highly fibrillated, well-differentiated pilocytic areas were intermingled with pleomorphic, microcystic tumor tissue. Immunohistochemical analysis of the tumor revealed that most of the neoplastic cells were immunoreactive for S-100 protein, with less intensity for glial fibrillary acidic protein (GFAP) and vimentin. A diagnosis of anaplastic astrocytoma was made on the basis of the histopathologic findings and immunohistochemical results. Moreover, there were similarities with the malignant variant of pilocytic astrocytoma described in human adults as an optic chiasmatic-hypothalamic glioma.
J Vet Sci. 2003 Aug;4(2):195-7. : Oligodendroglioma in a French bulldog.
Park CH.
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
parkc@svm.vetmed.wisc.edu

A 5-year-old, male French bulldog with bradycardia, dyspnea, and decerebrate rigidity was necropsied. Macroscopic findings were restricted to the brain, and a single mass, 1.5 x 2.0 x 1.5 cm in size, was observed mainly at the right cingulum with prominently protruding into the dilated right lateral ventricle. The mass was grayish white in color, soft and gelatinous, but not clearly delineated. Microscopically, the mass consisted of diffuse proliferated neoplastic oligodendroglial cells characterized by small, round, and hyperchromatic nuclei with clear cytoplasm and the cells aggressively invaded into the adjacent parenchyma. Immunohistochemistry demonstrated that most of the neoplastic cells were positive for S-100 protein, vimentin, neuron specific enolase (NSE), and neurofilament protein (NFP). From these findings, the mass was diagnosed as oligodendroglioma.
Int J Cancer. 2003 Jun 20;105(3):331-9.: Inhibition of phosphatidylinositol 3-kinase signaling negates the growth advantage imparted by a mutant epidermal growth factor receptor on human glioblastoma cells.
Klingler-Hoffmann M, Bukczynska P, Tiganis T.
Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia.

In de novo glioblastoma multiforme, loss of the tumour suppressor protein PTEN can coincide with the expression of a naturally occurring mutant epidermal growth factor receptor known as deltaEGFR. DeltaEGFR signals constitutively via the phosphatidylinositol 3-kinase (PI3K)/protein kinase Akt and mitogen-activated protein kinase pathways. In human U87MG glioblastoma cells that lack PTEN, deltaEGFR expression enhances tumourigenicity by increasing cellular proliferation. Inhibition of PI3K signaling with the pharmacologic inhibitor wortmannin, or by the reconstitution of physiological levels of PTEN to dephosphorylate the lipid products of PI3K, negated the growth advantage imparted by deltaEGFR on U87MG cells. PTEN reconstitution suppressed the elevated PI3K signaling, without affecting mitogen-activated protein kinase signaling and caused a delay in G1 cell cycle progression that was concomitant with increased cyclin-dependent protein kinase inhibitor p21CIP1/WAF1 protein levels. Our study provides insight into the mechanism by which deltaEGFR may contribute to glioblastoma development. Copyright 2003 Wiley-Liss, Inc.
J Am Anim Hosp Assoc. 2003 May-Jun;39(3):288-93. : Astrocytomas in young dogs.
Kube SA, Bruyette DS, Hanson SM.
Veterinary Centers of America, West Los Angeles Animal Hospital, 1818 South Sepulveda Boulevard, Los Angeles, California 90025, USA.

Primary brain tumors are not commonly reported in young dogs; however, they are the second most common cancer in children. Astrocytomas are the majority of these tumors. This report presents three cases of astrocytomas in young dogs, indicating a possible higher incidence than what is currently held. When suspected, it is recommended that biopsy or surgical excision be performed to further characterize and grade the tumor and, if appropriate, guide treatment.
An R Acad Nac Med (Madr). 2003;120(4):703-10; discussion 711-3. : [The canine model in the gene therapy of glioblastoma]
[Article in Spanish]
Izquierdo Rojo JM.

The group of research directed by Marta Izquierdo (in which I colaborate close to Dra. Garcia-Escudero and other colleagues) has used in the last three years the linamarase/linamarin system for treatment of brain tumors in the rat. This is a killer/suicide method based upon the plant linamarase gene, that hydrolyses the innocuous substrate linamarin to acetone cyanohydrin and glucose. The acetone cyanohydrin spontaneously breaks down to acetone and CNH, which kills the tumor cell. We try this system in dogs, but we could only induce tumors large enough to be treated by gene therapy in 2 out of 5 adult dogs. One of those dogs was treated with adenovirus carrying linamarase gene, and after with linamarine, observing the remission of the tumor. The other, used as control, died as a consecuence of the tumor. The W&W canine cell line seems to behave as allogeneic when injected into the brain of Beagle adult dogs, and is not, therefore an excellent model for this type.
1: J Vet Med Sci. 2003 Jan;65(1):113-5. : Ganglioglioma in the thalamus of a puppy.
Uchida K, Nakayama H, Endo Y, Kai C, Tatewaki S, Yamaguchi R, Doi K, Tateyama S.
Department of Veterinary Pathology, Faculty of Agriculture, Miyazaki University, Japan.

A solitary brain mass of a 4-month-old miniature dachshund showing seizure-like neurological signs was examined histopathologically. At necropsy a white tumor mass, replacing the thalamus, approximately 1.5 cm in diameter, was found. There was cystic space filled with yellowish pale fluid in the central area of the tumor mass. Histopathological examination revealed that the mass consisted of irregularly arranged well-differentiated neuronal and glial cells, and multifocal mineral deposits. The neuronal cells had a large clear nucleus and various amount of Nissl substances in the cytoplasm. Some neural cells were bi-nucleated. Neither mitotic figures nor proliferating cell nuclear antigen (PCNA)-positive nuclei was found in the neuronal cells. Immunostaining for glial fibrillary acidic protein (GFAP) revealed diffuse proliferation of GFAP-positive glial cells and their processes, while these glial cells did not show apparent cellular atypism, mitotic activity, or PCNA-immunoreactivity. Accordingly, the present tumor was diagnosed as ganglioglioma, and hamartomatous histogenesis might be possible.
1: Vet Clin Pathol. 2003;32(3):143-6. : Cerebrospinal fluid from a dog with neurologic collapse.
Thompson CA, Russell KE, Levine JM, Weeks BR.
Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station 77843-4467, USA.
cathompson@cvm.tamu.edu

A 3-year-old Staffordshire Terrier was presented to the Texas Veterinary Medical Center with a short progressive history of anorexia, weight loss, and weakness that had progressed to ataxia and collapse with empirical treatment. The dog was tetraparetic and obtunded. Results of a complete neurologic evaluation were consistent with severe, multifocal to diffuse disease involving the forebrain, spinal cord, and brainstem. Cerebrospinal fluid, obtained via cerebellomedullary cisternal puncture, was highly cellular and contained large atypical round cells with small numbers of nondegenerate neutrophils and large mononuclear cells. Rare eosinophils and small lymphocytes were noted. The atypical round cells were approximately 15-25 micro m in diameter with a single nucleus set in a small amount of cytoplasm. The nuclei were typically round to slightly ovoid; however, occasional notched, lobulated, and reniform nuclei were observed. These cells were interpreted as malignant lymphocytes. Owing to a grave prognosis, the animal was euthanized and a necropsy was performed. No gross lesions were found in the central nervous system. Multiple sections of cerebellum, medulla, and spinal cord contained a diffuse neoplastic infiltrate that was predominantly meningeal with rare superficial neuropil invasion. The neoplastic cells were arranged in sheets, cords, and rosettes. Immunohistochemical staining for vimentin, pancytokeratin, CD3, CD79a, synaptophysin, S-100, and neuron-specific enolase was negative; glial fibrillary acidic protein (GFAP) staining was equivocal. Based on histologic findings, a diagnosis of medulloblastoma was made. This case documents the rare occurrence of a canine medulloblastoma and illustrates the difficulty in distinguishing between some embryonal brain tumors and lymphoma.
1: J Vet Med Sci. 2002 Sep;64(9):863-6. : Secondary chronic respiratory acidosis in a dog following the cervical cord compression by an intradural glioma.
Hara Y, Nezu Y, Harada Y, Hasegawa D, Fujita M, Orima H, Tagawa M.
Division of Veterinary Surgery, School of Veterinary Medicine, Nippon Veterinary and Animal Science University, Kyonan-cho, Musashino-shi, Tokyo, Japan.

An intradural tumor in the upper cervical region was found in a dog with quadriparesis and chronic respiratory acidosis. Surgical removal of the tumor in the atlas and intraoperative radiotherapy were attempted. The tumor was histologically diagnosed as a neural glioma. A preoperative acid-base disturbance was dramatically improved after surgery. The clinical changes appeared in this case suggest that compression of the spinal cord at this region may cause paralysis of the respiratory muscles and secondarily result in chronic respiratory acidosis following the respiratory insufficiency.
Eur J Cancer. 2002 Mar;38(5):696-704. : Contacts with animals and humans as risk factors for adult brain tumours. An international case-control study.
Menegoz F, Little J, Colonna M, Arslan A, Preston-Martin S, Schlehofer B, Blettner M, Howe GR, Ryan P, Giles GG, Rodvall Y, Choi WN.
Registre du cancer de l'Isere, 21 Chemin des Sources, 38240 Meylan, France.
registre.cancer.isere@wanadoo.fr

While numerous studies have addressed the possible role of farming and related exposures as risk factors for brain tumours in adults, few of them have examined the potential effect of exposure to farm animals or pets. In an international multicentre case-control study, we investigated whether residence on a farm, contact with animals, or working in occupations with a high degree of potential contact with animals or humans were associated with brain tumours. Using a common questionnaire, 1177 cases of glioma, 330 with meningioma and 2478 controls from eight centres were interviewed about the exposures and, in particular, about their contacts with nine species of animals: dairy cattle, beef cattle, pigs, horses, sheep, goats, poultry, dogs and cats. Living or working on a farm was not a risk factor, for either glioma or meningioma. Except in some centres, there was no relationship between having contacts with farm animals or pets and the risk of brain tumour, for either type of tumour or either sex. In relation to seven industrial groups involving frequent human and/or animal contacts, no association was apparent for either glioma or meningioma. In relation to 25 occupational groups with potential frequent contact with humans and/or animals, for glioma there was a reduced risk for biological technicians (Odds Ratio (OR)/=0, P=0.01), and general farm workers (OR=0.66, 95% Confidence Interval (CI): 0.5-0.9). For meningioma, there was an increased risk for cooks (OR=2.0; CI: 1.2-3.4). With some exceptions, these results indicate no association between either the type of brain tumour and contacts with animals, or with occupations that include a high level of contact with animals or a high level of contact with humans.
Vet Radiol Ultrasound. 2004 Mar-Apr;45(2):149-55.: Material in the middle ear of dogs having magnetic resonance imaging for investigation of neurologic signs.
Owen MC, Lamb CR, Lu D, Targett MP.
Department of Veterinary Clinical Sciences, The Royal Veterinary College, University of London, London, UK.

The aim of this study was to determine the prevalence and potential significance of finding material in the middle ear of dogs having magnetic resonance (MR) imaging. Of 466 MR studies reviewed, an increased signal was identified in the tympanic bulla in 32 (7%) dogs. Cavalier King Charles spaniels, Cocker spaniels, Bulldogs, and Boxers were over-represented compared to the population of dogs having MR imaging. Five (16%) dogs had definite otitis media and one (3%) had a meningioma invading the middle ear. Of the remaining dogs, 13 (41%) had possible otitis media and 13 (41%) had neurologic conditions apparently unrelated to otitis media. The most common appearance of material in the middle ear was isointense in T1-weighted images and hyperintense in T2-weighted images. There was no apparent correlation between the signal characteristics of the material and the diagnosis. Enhanced signal after gadolinium administration was observed affecting the lining of the bulla in dogs with otitis media and in dogs with unrelated neurologic conditions. In dogs without clinical signs of otitis media, finding an increased signal in the middle ear during MR imaging may reflect subclinical otitis media or fluid accumulation unrelated to inflammation. Brachycephalic dogs may be predisposed to this condition.
Vet Clin Pathol. 2004;33(2):111-4.: Cytology of a mass on the meningeal surface of the left brain in a dog.
Sharkey LC, McDonnell JJ, Alroy J.
Department of Biomedical Sciences, Tufts University School of Veterinary Medicine, North Grafton, MA., USA,
shark009@umn.edu

An 11-year-old neutered male Labrador Retriever presented to Tufts University School of Veterinary Medicine for a 2-week history of seizures and altered behavior. Magnetic resonance imaging (MRI) revealed a homogeneously enhancing mass involving the surface of the left temporal, parietal, and occipital lobes of the brain, causing secondary hydrocephalus. Cytology samples obtained during rostrotentorial craniectomy contained abundant amorphous pink material suggestive of neuropil, scattered leukocytes, capillary fragments, large polyhedral nerve cell bodies, and other smaller cells with pale blue cytoplasm that occasionally were vacuolated and contained fine eosinophilic granules. The cytologic diagnosis was neoplasia, possibly meningioma. Ninety days after surgery the patient was euthanized after MRI results confirmed regrowth of the tumor. Histologic samples of the meningeal lesion collected at necropsy consisted of sheets and nests of loosely packed, large polygonal cells that compressed the brain parenchyma. The cytoplasm was eosinophilic and slightly granular, whereas nuclei were dense and eccentric. Neoplastic cells stained positive for S-100 protein, periodic acid-Schiff, and were partially diastase resistant. Vimentin staining was negative. Ubiquitin staining was light but diffusely positive. Ultrastructural features of the neoplastic cells included numerous secondary lysosomes and irregular pleomorphic nuclei. The final diagnosis was meningeal granular cell tumor. This case documents the cytologic and histologic features of an uncommon type of meningeal tumor.
Am J Vet Res. 2003 Oct;64(10):1310-8.: Evaluation of progesterone and estrogen receptor expression in 15 meningiomas of dogs and cats.
Adamo PF, Cantile C, Steinberg H.
Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA

OBJECTIVE: To evaluate progesterone and estrogen receptor expression in meningiomas of the CNS in dogs and cats. ANIMAL: 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. RESULT: 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.
Berl Munch Tierarztl Wochenschr. 2003 Sep-Oct;116(9-10):436-42. : Erratum in: Berl Munch Tierarztl Wochenschr. 2003 Nov-Dec;116(11-12):527.
[Computertomographic characteristics of primary brain tumors in dogs and cats]
[Article in German]
Fuchs C, Meyer-Lindenberg A, Wohlsein P, Nolte I.
Klinik fur kleine Haustiere der Tierarztlichen Hochschule Hannover.

Since computed tomography (CT) was introduced to veterinary medicine in the beginnings of the 80s, the CT of the skull has mainly been used for the diagnosis of brain tumors. The present study includes 18 dogs and five cats, all patients of the Clinic of Small Animals of the School of Veterinary Medicine Hannover. After a CT of their skull was made, a primary intracranial neoplasm was confirmed by a pathomorphological and -histogical examination post mortem. Four of the five cats had a meningioma, one cat an astrocytoma. With five cases the meningioma also predominated in the dogs, followed by primary lymphoma with four cases. An astrocytoma, an oligodendroglioma and a choroid plexus papilloma were diagnosed respectively in two dogs. A pituitary gland tumor, a germ cell tumor and a medulloblastoma represented individual cases. Based on the pathomorphologically and -histologically confirmed diagnosis, characteristics of these primary brain neoplasms can be found in their CT image. However, changes are not pathognomonic for a certain type of tumor; a definitive diagnosis cannot be made from the CT image.
J Am Vet Med Assoc. 2002 Dec 1;221(11):1597-600. : Surgery alone or in combination with radiation therapy for treatment of intracranial meningiomas in dogs: 31 cases (1989-2002).
Axlund TW, McGlasson ML, Smith AN.
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.

OBJECTIVE: To compare, for dogs with intracranial meningiomas, survival times for dogs treated with surgical resection followed by radiation therapy with survival times for dogs treated with surgery alone. DESIGN: Retrospective study. ANIMALS: 31 dogs with intracranial meningiomas. PROCEDURE: Medical records of dogs with histologic confirmation of an intracranial meningioma were reviewed. For each dog, signalment, clinical signs, tumor location, treatment protocol, and survival time were obtained from the medical record and through follow-up telephone interviews. RESULTS: Dogs that underwent tumor resection alone and survived > 1 week after surgery had a median survival time of 7 months (range, 0.5 to 22 months). Dogs that underwent tumor resection followed by radiation therapy had a median survival time of 16.5 months (range, 3 to 58 months). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in dogs with intracranial meningiomas, use of radiation therapy as a supplement to tumor resection can significantly extend life expectancy
: J Comp Pathol. 2002 Aug-Oct;127(2-3):214-8.: Immunohistochemical identification and image analysis quantification of oestrogen and progesterone receptors in canine and feline meningioma.
Mandara MT, Ricci G, Rinaldi L, Sarli G, Vitellozzi G.
Department of Veterinary Public Health and Animal Pathology, School of Veterinary Medicine, Bologna, Italy.

Oestrogen and progesterone receptor expression has been detected in human meningioma; in canine and feline meningiomas, however, the identification of steroid receptors requires further investigation. Fourteen meningiomas obtained from nine dogs and five cats were examined immunohistochemically for oestrogen receptors (ORs) and progesterone receptors (PRs). The immunolabelling reaction was quantified by light microscopy and image analysis. ORs were expressed in low numbers in two feline meningiomas and in one canine meningioma. PRs were more numerous, with more extensive tissue labelling. Conventional linear regression analysis showed that OR expression was not significant as compared with PR expression. PR expression was lowest in meningiomas with a high proliferation index, as determined by Ki67 expression. Conventional linear regression analysis between PR and Ki67 concentration confirmed a significant indirect relationship
J Small Anim Pract. 2002 Jun;43(6):272-4. :ks Cystic meningioma in a dog.
Kitagawa M, Kanayama K, Sakai T.
Department of Preventive Veterinary Medicine and Animal Health, Nihon University School of Veterinary Medicine, Fujisawa, Kanagawa, Japan.

There have been few reports of the occurrence of, and treatment methods for, cystic meningioma in the dog. This report describes a case in a Maltese which presented with a three-month history of seizures. Cystic meningioma was diagnosed by magnetic resonance imaging using contrast medium (gadoteridol) enhanced images. Attempted surgical removal of the mass was successful, and the outcome following surgery was good.
Vet Pathol. 2002 May;39(3):311-21. : Immunohistochemical staining patterns of canine meningiomas and correlation with published immunophenotypes.
Barnhart KF, Wojcieszyn J, Storts RW.
Department of Veterinary Pathobiology, Texas A&M University, College of Veterinary Medicine, College Station 77833-4457, USA.
kbarnhart@cvm.tamu.edu

This study examined immunohistochemical staining patterns for several meningioma variants involving either the brain or spinal cord of dogs. Formalin-fixed, paraffin-embedded tissue from 15 tumors was obtained. The selected tumor group included seven meningothelial, three transitional, two malignant (anaplastic), one myxoid, one papillary, and one osteomatous meningiomas. Tumors were evaluated for reactivity to the following six immunohistochemical markers: vimentin, pancytokeratin, glial fibrillary acidic protein (GFAP), S100, neuron-specific enolase (NSE), and synaptophysin. Vimentin expression was detected in all meningiomas, and 14 of 15 tumors demonstrated intense vimentin staining in more than 50% of the neoplastic cells. Pancytokeratin expression was present in 11 of 15 neoplasms; however, positive staining frequently was focal and often involved a small percentage of the neoplastic cells. GFAP expression was detected in a single, anaplastic meningioma. Although expression of NSE and S100 was detected in 12 of 25 meningiomas, the intensity of the staining and the percentage of positive neoplastic cells was highly variable. Synaptophysin was uniformly negative. These results will help to establish immunohistochemical profiles for meningiomas that will improve our ability to correctly differentiate these neoplasms of meningeal origin from central nervous system tumors originating from other sites.
Am J Vet Res. 2002 Mar;63(3):381-6. : Evaluation of rapid staining techniques for cytologic diagnosis of intracranial lesions.
Long SN, Anderson TJ, Long FH, Johnston PE.
Department of Small Animal Clinical Studies, University of Glasgow Veterinary School, Bearsden, UK.

OBJECTIVE: To evaluate 4 rapid supravital stains and 3 preparation techniques for use in the intraoperative diagnosis of intracranial lesions. ANIMALS: 10 dogs and 1 cat euthanatized for intracranial lesions. PROCEDURE: Specimens were taken from lesions and slides prepared, using 3 techniques: touch impression, medium-pressure impression, or smear preparation. Preparations were then stained with 4 stains: modified Wright stain, May-Grunwald-Giemsa, toluidine blue, and zynostain and examined in a blinded randomized fashion. Cytologic diagnosis was compared with histopathologic diagnosis and classified on the basis of identification of the pathologic process and specific diagnosis into the following categories: complete correlation, partial correlation, or no correlation. RESULTS: An overall diagnostic accuracy of 81% (107/132) was achieved on the basis of a combination of partial and complete correlation. Of the stains examined, modified Wright stain appeared to be most accurate, with complete correlation in 17 of 33 (52%) specimens and partial correlation in 12 of 33 (36%) specimens. Of the preparation methods, touch preparation and smear preparation provided the most accurate results, with an overall diagnostic accuracy of 82% (36/44) for both methods. However, smear preparations appeared to be of greater diagnostic value, with fewer nondiagnostic specimens, compared with touch preparations. CONCLUSIONS AND CLINICAL RELEVANCE: Cytologic preparations provide a useful diagnostic tool for the intraoperative diagnosis of intracranial lesions. All stains examined yielded promising results, the most accurate of which appeared to be the modified Wright stain. The smear preparation appeared to be the preparation method of greatest diagnostic value.
J Vet Med Sci. 2002 Feb;64(2):155-7. : Cerebellar myxoid type meningioma in a Shih Tzu dog.
Suzuki M, Nakayama H, Ohtsuka R, Yasoshima A, Katayama K, Uetsuka K, Ohta M, Matsunaga S, Ogawa H, Uchida K, Doi K.
Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan.

A 6-year and 9 month-old, male, Shih Tzu dog showed ataxia and trembling. By MRI examination, a mass (1 cm) was found in the right cerebellum. As the dog did not respond to radiation therapy, and showed a rise of intracranial pressure, he was euthanized. The cerebellar mass was soft and hemorrhagic. Histologically, the mass contained vimentin-positive spindle- or polyhedral-shaped cells arranged in a cord-like pattern. Mucinous materials were observed in the intercellular spaces. Ultrastructural examination revealed cell processes, microtubule-like structures and desmosomes. The case was diagnosed as myxoid type meningioma.
Vet Surg. 2002 Jan-Feb;31(1):65-9.: Comparison of fine-needle aspiration and surgical-tissue biopsy in the diagnosis of canine brain tumors.
Platt SR, Alleman AR, Lanz OI, Chrisman CL.
Center for Small Animal Studies, The Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, England.

OBJECTIVE: To compare the diagnoses obtained using fine-needle aspiration (FNA) and surgical-tissue biopsy of focal cerebral masses with the histologic diagnoses obtained via necropsy. STUDY DESIGN: A prospective case series. SAMPLE POPULATION: Ten client-owned adult dogs of various breeds. All dogs had clinical signs of cerebral disease and had a focal brain mass identified using magnetic resonance imaging; all were eventually euthanatized. METHODS: Immediately after euthanasia, the brains were removed en bloc from the cranial cavity. FNAs were obtained from each mass using a 22-gauge hypodermic needle and a 12-mL syringe. Cytologic preparations were made from each aspirate. A 14-gauge Tru-cut biopsy needle was used to obtain a core tissue sample from each mass. The biopsy specimens were fixed in 10% buffered formalin and submitted for histologic evaluation. The brains were similarly fixed and stained. Six-micrometer-thick transverse sections of the brain were examined microscopically. RESULTS: Neoplasia was confirmed in all dogs histologically in the 6-microm transverse sections. Four meningiomas, 2 astrocytomas, 2 oligodendrogliomas, 1 pituitary adenocarcinoma, and 1 neurofibrosarcoma were identified. FNA correctly identified all of the masses as neoplastic. Cytologic diagnoses correlated with the histologic interpretation in 5 of the masses (50%). Tru-cut biopsy specimens identified all 10 masses as neoplastic; in 9 of the 10 (90%), the diagnosis correlated with the histologic diagnosis. CONCLUSIONS AND CLINICAL RELEVANCE: FNA is a sensitive method that can be used to determine the presence of neoplasia in the brain, but is not as definitive as the Tru-cut biopsy in determining the specific type of cerebral neoplasm. Copyright 2002 by The American College of Veterinary Surgeons
J Am Vet Med Assoc. 2001 Dec 1;219(11):1562-7, 1550. : Radiosurgery using a stereotactic headframe system for irradiation of brain tumors in dogs.
Lester NV, Hopkins AL, Bova FJ, Friedman WA, Buatti JM, Meeks SL, Chrisman CL.
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA.

Radiation therapy of brain tumors in dogs typically involves administration of multiple fractions over several weeks. Fractionation is used to minimize damage to normal tissue. Radiosurgery uses multiple non-coplanar stereotactically focused beams of radiation in a series of arcs to deliver a single dose to the target with extreme accuracy. The large number of beams facilitates a high degree of conformation between the treatment area and the target tumor and allows for a steep dose gradient; the use of nonintersecting arcs minimizes exposure of normal tissue. Computed tomography with a stereotactic localizer secured to the skull allows generation of a 3-dimensional image of the target and provides accurate spatial coordinates for computerized treatment planning and delivery. Three dogs were treated with radiosurgery, using 1,000 to 1,500 cGy. A linear accelerator mounted on a rotating gantry was used to generate and deliver the radiation. Two dogs with meningiomas survived 227 and 56 weeks after radiosurgery. A dog with an oligodendroglioma survived 66 weeks. No complications were observed following the use of this technique.
J Comp Pathol. 2001 Feb-Apr;124(2-3):227-30.: Papillary meningioma in the dog: a clinicopathological study of two cases.
Kaldrymidou E, Polizopoulou ZS, Papaioannou N, Koutinas AF, Poutahidis T, Papadopoulos G.
Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, 54006 Thessaloniki, Greece.

Two cases of canine papillary meningioma are reported. The first animal, an 11-year-old male Boxer, presented with vestibular ataxia and the tumour was located in the left pontomedullary region. The second animal, a 15-year-old female cross-bred Miniature Poodle, presented with dementia, truncal ataxia and hypermetria, and the tumour was located in the right semilunar ganglion of Gasser. In the first case, histopathological examination showed that the papillary pattern merged with a typical syncytial meningioma, with extensive areas of necrosis. In the second case, the multilobular tumour had lobules with a purely syncytial, fibrous or transitional histological pattern, and lobules with intermingling papillary and secretory histological patterns. Both tumours exhibited histological features of malignancy, but evidence of remote metastasis was not found. Copyright Harcourt Publishers Ltd.
Vet Pathol. 2000 Nov;37(6):653-5. : Meningeal osteosarcoma in a dog.
Ringenberg MA, Neitzel LE, Zachary JF.
Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana 61802, USA

A meningeal osteosarcoma was diagnosed in a dog displaying neurologic signs compatible with a space-occupying cerebellar lesion. Gross lesions, restricted to the brain, consisted of a solitary, compressive mass attached to the dura mater overlying the left cerebellum. The mass was composed of single and multinucleated, atypical polygonal cells that lined or rested within lacuna surrounded by eosinophilic, mineralized matrix. The matrical component stained dark green-yellow to blue with Movat's pentachrome stain, deep blue to red with Heidenhain aniline blue stain, and brown-black with Von Kossa stain. Results of these stains were interpreted as tumor osteoid. Foci of dural mineralization and osseous metaplasia were present at the point of tumor attachment. The microscopic observations were interpreted as an osteosarcoma of extraskeletal origin. To our knowledge, these findings represent the first documented case of a meningeal osteosarcoma in a domestic animal species.