Abstract. 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 ϭ 5), sharp borders (n ϭ 4), ring enhancement (n ϭ 3), heterogenous T2-weighted signal intensity (n ϭ 3), iso-to hypointense T1-weighted images (n ϭ 5), necrosis (n ϭ 5), and cyst formation (n ϭ 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.

The cervical spine of 21 dogs with clinical signs of cervical stenotic myelopathy was evaluated using magnetic resonance (MR) imaging. Spin echo T1, T2 and gradient echo T2 weighted images were obtained with a 1.5 Tesla magnet in 12 dogs and a 1.0 Tesla magnet in 9 dogs. Sagittal or parasagittal T1W and T2W images were helpful in determining the presence of spinal cord compression or degenerative disease of the articular processes. Transverse T1W and T2W images were the most useful for the identification of dorsolateral spinal cord compression secondary to soft tissue and ligament hypertrophy, as well as synovial cysts, associated with the articular processes. The MR imaging findings were consistent with the surgical findings in all 14 dogs that underwent surgery. Magnetic resonance imaging provided a safe, non-invasive method of evaluating the cervical spine in dogs suspected of having cervical stenotic myelopathy. Veterinary

Spinal cord dysfunction secondary to spinal arachnoid cysts (SACs) has been reported previously in dogs. This retrospective study reviews the clinical signs, radiographic findings, and outcome after surgical resection of SACs in 14 dogs. Plain vertebral column radiographs and myelography were done in all dogs. Computed tomography (CT) was done in 7 dogs and magnetic resonance (MR) imaging in 3 dogs. Affected dogs were between 1 and 12 years of age, and 8 of 14 were Rottweilers. Abnormalities detected on neurological examination depended on the location of the SAC. Five dogs had bilobed or multiple SACs. SACs were located in the cervical vertebral column in 11 dogs and in the thoracic vertebral column in 4 dogs. All dogs had dorsally or dorsolaterally located SACs. Two dogs also had additional ventrally located SACs. Spinal cord compression secondary to intervertebral disc extrusion or protrusion was demonstrated at the site of the SACs in 2 dogs. Surgical resection of the SACs was completed in all dogs. Eleven dogs were available for follow-up. Five weeks postoperatively, 7 dogs improved in neurological function, with some residual ataxia and paresis in 6 of these dogs. Neurological function had deteriorated in 4 dogs. It was concluded from this study that Rottweilers have a higher incidence of SACs than other breeds of dog. Furthermore, bilobed or multiple SACs can occur commonly, and myelography effectively localized SACs in dogs. Surgical resection of SACs resulted in improvement in neurological function in the majority of treated dogs.Key words: Canine; Myelogram; Neuroimaging; Rottweiler; Subarachnoid cyst. Spinal arachnoid cysts (SACs) have been reported previously as a cause of neurological dysfunction in dogs and cats. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Although most cysts are thought to be congenital, SACs have been reported in association with spinal cord trauma and intervertebral disc disease.1-10 Thirty-nine cases of SACs have been reported previously. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In the majority of these reports, there was no age, breed, or gender predilection for cyst occurrence. In 1 report, 6 of 11 dogs were Rottweilers. 16 In most dogs, SACs were located dorsal or dorsolateral to the spinal cord, and in 4 dogs, multiple cysts were reported. In 3 dogs, multiple cysts were present at the same location and in another dog the cysts were located at 2 different anatomic sites. 9,16 Two of the dogs with multiple SACs at the same location also had a ventrally located SAC. 16 Of the 39 dogs previously reported, SACs were located only in the cervical vertebral column in 23 dogs, only in the thoracic vertebral column in 15 dogs, and in both the cervical and thoracic vertebral column in 1 dog. Myelography was used to diagnose SACs in all reports. In 9 dogs, computed tomography (CT) was done, and in 4 dogs, magnetic resonance (MR) imaging was done in addition to myelography to further evaluate the location of SACs. Surgical removal of the SAC was performed in 3...

There is a lack of effective means of promoting remyelination of the central nervous system (CNS) in humans with chronic demyelinating disease. We have investigated the ability of transplanted glia to myelinate areas of the CNS equivalent to focal demyelinated lesions in multiple sclerosis (MS). In these studies we show that transplantation of oligodendrocytes or their progenitors into the CNS of a neonatal or adult canine myelin mutant results in repair of large areas similar in size to many MS plaques. Progenitor or pre-progenitor cells of the oligodendrocyte lineage have the greatest capacity for myelination following grafting, although cells of neonatal origin may also be used. Such an approach may therefore have therapeutic value in the repair of focal lesions in human myelin disease.

A 6-year-old neutered female Boston Terrier had a slow onset of blindness and behavior changes. Neurologic abnormalities included bilateral visual loss with absent menace responses and visual tracking, mydriatic pupils, slow pupillary light responses and papilledema. On magnetic resonance imaging (MRI) there were multiple cyst-like structures found in the parenchyma of the cerebrum, cerebellum and brainstem. Histopathologically the diagnosis was a choroid plexus carcinoma with meningeal carcinomatosis. The findings differ from previous descriptions of the MRI characteristics of choroid plexus tumors.