A feline spinal dermoid cyst treated with surgical intervention

A 5-year-old neutered female mixed cat presented with reduced activity and ataxia of the hind limbs. Computed tomography and magnetic resonance imaging revealed an extradural mass compressing the spinal cord on the dorsal aspects from the 7th to 8th thoracic vertebra. Dorsal laminectomy was performed on the 7-8th thoracic vertebra and the cyst was totally removed, giving full resolution of the clinical signs. The cyst was diagnosed as a dermoid cyst. To our knowledge, this is the first report of feline dermoid cyst compressing the spinal cord that was diagnosed antemortem. The prognosis is favorable when the cyst is completely resected.

Magnetic resonance imaging findings of the primitive neuroectodermal tumour in lumbosacral spinal cord in a cat

A 5-year-old, castrated, male domestic short-haired cat presented with neurological deficits in the pelvic limbs, back pain and dysuria. Magnetic resonance imaging showed a mass lesion caudal to the L4 vertebrae. In addition, suspected haemorrhage was observed at the cranial aspect of the mass. There was no evidence to support the presence of extravertebral intrusion or vertebral body, osteolysis. Dorsal laminectomy and durotomy were performed to debulk the intraspinal mass. Histopathological and immunohistochemical assessment revealed a primitive neuroectodermal tumour (PNET). To our knowledge, this is the first report to describe the clinical and pathological features and imaging diagnosis of intraspinal PNET without extraspinal invasion in a cat.

A long survival case of spinal nephroblastoma in a dog

Background:

Dogs’ nephroblastoma of the spinal cord is a rare neoplastic disease, with few reports of long-term survival after surgery. We experienced that surgical treatment with postoperative radiation therapy for spinal nephroblastoma in a dog resulted in the long-term survival of 11 years.

Case Description:

The patient presented to our veterinary hospital because of progressive hindlimb paralysis. Based on diagnostic imaging, she was diagnosed with a thoracolumbar spinal cord tumor and was treated with surgery. The gross tumor tissue was removed after laminectomy, followed by postoperative radiation therapy using orthovoltage equipment. The histopathological features of the surgical specimen were consistent with those of previously reported spinal nephroblastoma, although infrequent mitotic figures were observed. The dog recovered well after treatment and resumed her normal walking condition. No tumor recurrence was observed on periodic follow-up magnetic resonance imaging performed 10 and 21 months after surgery. Imaging evaluation for the gradual development of hindlimb weakness was performed 9 years after surgery; however, no recurrence of tumor tissue was observed, and spondylosis deformans, probably induced after laminectomy, were identified as a possible cause. The dog died of aspiration pneumonia 11 years after surgery, independent of spinal nephroblastoma.

Conclusion:

To date, no clinical cases of canine spinal cord primary nephroblastoma that survived for 11 years after surgery have been reported. This case strongly suggests that providing intensive treatment for canine spinal nephroblastoma is very important.

Oligodendroglioma in the Cervical Spinal Cord of a Dog

A 7-year-old male castrated Yorkshire Terrier dog developed slowly progressive neurologic disturbances consisting of difficulties in moving the neck, lack of proprioception, and tetraparesis 4 months prior its death. Neurologic examination, computer tomography, and myelography resulted in the tentative diagnosis of intramedullary cervicothoracic spinal cord lesion. At necropsy, an intramedullary cervical spinal cord mass between C5 and C6 was noticed. Histologically, cells of this well-demarcated, nonencapsulated neoplasm were arranged in sheaths or cords separated by a fine fibrovascular stroma. The polygonal to round tumor cells were characterized by moderate pale, basophilic, and vacuolar cytoplasm and round to slightly oval, centrally located nuclei with fine-stippled heterochromatin, a single nucleolus, and a very low mitotic activity. Tumor cells lacked glial fibrillary acidic protein, vimentin, factor VIII-related, and cytokeratin antigen expression. Histologic and immunohistochemical findings led to the diagnosis of a cervical spinal cord oligodendroglioma.

Infiltrative Spinal Lipoma in a Canada Goose (Branta canadensis)

An adult Canada goose ( Branta canadensis ) was presented unable to walk. On physical examination, conscious proprioception was absent in both legs, and motor function was decreased. The bird did not improve with supportive care and was euthanatized and submitted for postmortem examination. Sagittal sectioning of the spine revealed an intradural growth causing segmental deformity of the lumbosacral spinal cord. The growth was diagnosed as an infiltrative spinal lipoma. Infiltrative lipomas are locally invasive, benign tumors that can be found in any host tissue. They have been documented in small and exotic companion animals, including birds; however, this is the first report of an infiltrative lipoma in the spinal canal of a bird or free-living wild animal.

Focal thoracolumbar spinal cord lymphosarcoma in a ferret (Mustela putorius furo)

A 6-year-old, castrated male domestic ferret (Mustela putorius furo) was euthanized following progressive hind limb paresis and atonia of the bladder of 1-year duration. Neurological evaluation localized the lesion to the thoracolumbar spinal region, and magnetic resonance imaging showed a focal intramedullary spinal cord lesion. Histopathology revealed an extensive, unencapsulated, poorly demarcated mass within the thoracolumbar spinal cord, diagnosed as lymphosarcoma.

Myelomeningocoele and a dermoid sinus-like lesion in a French bulldog

A 2-year-old male French bulldog was presented for investigation of lumbosacral pain and hindlimb ataxia associated with urinary and fecal incontinence. Survey radiography, myelography, and computed tomography images were suggestive of a dermoid sinus with associated spina bifida. Surgical intervention led to a resolution of pain and neurological deficits. Histopathological analysis of the excised tissue was compatible with a myelomeningocoele of the 7th lumbar vertebra.

Infiltrative lipoma compressing the spinal cord in 2 large-breed dogs

Two cases of infiltrative lipomas compressing the spinal cord and causing nonambulatory paraparesis in 2 large-breed dogs are reported. Magnetic resonance imaging (MRI) revealed severe extradural spinal cord compression by inhomogenous masses that infiltrated the adjacent tissues and the muscles of the spine in both dogs. The presumptive clinical diagnoses were infiltrative lipomas, which were confirmed by histopathology. In rare cases infiltrative lipomas are able to compress the spinal cord by the agressive growth of invasive adipocytes causing neurological deficits.

Comparative imaging of spinal extradural lymphoma in a Bordeaux dog

A lumbar extradural lymphoma compressing the spinal cord was identified on contrast enhanced computed tomography (CT) and magnetic resonance imaging (MRI) images in a 4-year-old Bordeaux dog presented with posterior paresis. A significant paravertebral extension was only clearly defined on contrast MRI images; therefore, MRI was more useful than CT in imaging of spinal extradural lymphoma in this dog.

Hind-limb paresis in a dog with paralumbar solitary T-cell lymphoma

A 2-year-old, neutered, male golden retriever was referred to the Ontario Veterinary College, with a 6-week history of hind limb weakness and back pain. Magnetic resonance imaging of the lumbar vertebral column, and histopathology and immunohistochemistry following euthanasia identified an uncommon solitary T-cell lymphoma in the paralumbar area.

[Multiple myeloma in a Yucatan Pig]

An 11 years old Yucatan Pig with a Multiple Myeloma in the spinal cord, the sternum and the pelvis is described. The major clinical sign was a paresis of the hind limb. The most significant haematological change was a lymphopenia. The X-ray examination and computed tomography showed typical osteolytic changes in the skeleton. The histological examination of the bone marrow showed many, moderately well-differentiated plasma cells. Based on the collected findings and the exclusion of differential diagnoses, a Multiple Myeloma was diagnosed.

Surgical management of a recurrent spinal meningioma in a cat

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.

Teratoma in the Cervical Spinal Cord of a Dog

An 11-year-old, spayed female giant schnauzer was presented for evaluation of chronic, progressive tetraparesis. Diagnostic imaging was consistent with intervertebral disk protrusion, and surgical decompression and stabilization were performed. Postoperatively the dog did not improve, and further imaging suggested an intramedullary mass at the level of the sixth cervical vertebra. The dog was euthanized 7 days after surgery, and a teratoma was found postmortem.

A true "triphasic" pattern: thoracolumbar spinal tumor in a young dog

An 8-month-old male Bernese Mountain Dog was referred with a history of hindlimb weakness that progressed to paresis on the right side. An intradural mass was detected in the spinal canal at the level of the 2nd and 3rd lumbar vertebrae. During surgical removal, 2 small fragments of the mass were prepared for cytologic examination by the squash technique. Cytologic examination revealed 3 different cell types: mesenchymal (stromal) cells, epithelial cells, and small undifferentiated hyperchromatic cells. On the basis of location and the triphasic cytologic pattern, a diagnosis of spinal nephroblastoma (thoracolumbar spinal tumor of young dogs) was made; histologic examination of the mass confirmed the cytologic diagnosis. To our knowledge, this is the first report of a triphasic pattern in a cytologic sample; recognizing this pattern is an important aid in reaching a definitive cytologic diagnosis.

Spinal nephroblastoma in a miniature Dachshund

A 2-year-old castrated miniature Dachshund dog was presented to the Rakuno Gakuen Veterinary Teaching Hospital for diagnosis of progressive hindlimb paresis and ataxia. There was no thoracolumbar intervertebral disk hernia and magnetic resonance imaging revealed an intramedullary spinal cord lesion at the ninth and tenth thoracic vertebrae. Following surgical excision of the neoplasm, there was minor amelioration of neurological signs, but forelimb function was not recovered. The extracted tumor was histopathlogically diagnosed as spinal nephroblastoma.

Imaging diagnosis--infiltrative lipoma causing spinal cord compression in a dog

An 11-year-old, 43 kg neutered female Labrador retriever dog developed acute pelvic limb paraparesis. In magnetic resonance images there was a T1- and T2-hyperintense extradural at the fifth thoracic intervertebral space that was causing marked compression of the spinal cord. In short tau inversion recovery and fat suppressed T1-weighted images the signal from the mass was decreased indicating it was of fatty origin. The mass was removed via a dorsal hemilaminectomy in the thoracic area. Histopathologic analysis confirmed the mass was an infiltrative lipoma. The dog recovered and is fully ambulatory 24 months after surgery. This report provides additional evidence that lipomas in the vertebral canal may be the source of pelvic limb neuropathy and also illustrates the value of magnetic resonance imaging in establishing the fatty nature of some soft tissue masses.

Primitive neuroectodermal tumor in the spinal cord of a brahman crossbred calf

A variety of embryonal tumors of the central nervous system, typically malignant and occurring in young individuals, are recognized in humans and animals. This report describes an invasive subdural but predominantly extramedullary primitive neuroectodermal tumor developing at the lumbosacral junction in a 6-month-old Brahman crossbred calf. The tumor was composed of spindloid embryonal cells organized in interlacing fascicles. The cells had oval to elongate or round hyperchromic nuclei, single to double nucleoli, and scant discernible cytoplasm. Immunohistochemical staining for neuron-specific enolase, synaptophysin, and S-100 protein and formation of pseudorosettes suggested neuronal and possibly ependymal differentiation.

Neuroblastoma with neuronal differentiation in the spinal cord in an Aberdeen Angus heifer calf

A 5-month-old, female, Aberdeen Angus heifer presented to the veterinary medical teaching hospital for evaluation of slowly progressive hindlimb ataxia. The calf was clinically normal until 4 months of age, following routine pregnancy and delivery. Neurologic examination revealed marked symmetric spastic hindlimb paraparesis. Thoracolumbar radiographs and cerebrospinal fluid (CSF) analysis were unremarkable. A presumptive diagnosis of T3-L3 myelopathy was made, and neurologic status remained static for 3 months with broad-spectrum antibiotic and nonsteroidal anti-inflammatory therapy. Additional diagnostic tests were refused, and a necropsy was performed following euthanasia. A moderately well delineated, reddish-tan, soft mass 18 mm in diameter replaced 80% of the fourth lumbar spinal cord segment. Histologic examination revealed two distinct features: undifferentiated, primitive, polygonal-to-round cells with typical morphologic characteristics of primitive neuroectoderm; and interspersed areas containing myelinated axons and cells with neuronal differentiation. Immunohistochemical examination confirmed the presence of primitive neuroepithelium and cells with neuronal differentiation.

VALUE OF A SINGLE-SHOT TURBO SPIN-ECHO PULSE SEQUENCE FOR ASSESSING THE ARCHITECTURE OF THE SUBARACHNOID SPACE AND THE CONSTITUTIVE NATURE OF CEREBROSPINAL FLUID

Three case history reports are presented to illustrate the value of the single-shot turbo spin-echo pulse sequence for assessment of the subarachnoid space. The use of the single-shot turbo spin-echo pulse sequence, which is a heavily T2-weighted sequence, allows for a rapid, noninvasive evaluation of the subarachnoid space by using the high signal from cerebrospinal fluid. This sequence can be completed in seconds rather than the several minutes required for a T2-fast spin-echo sequence. Unlike the standard T2-fast spin-echo sequence, a single-shot turbo spin-echo pulse sequence also provides qualitative information about the protein and the cellular content of the cerebrospinal fluid, such as in patients with inflammatory debris or hemorrhage in the cerebrospinal fluid. Although the resolution of the single-shot turbo spin-echo pulse sequence images is relatively poor compared with more conventional sequences, the qualitative information about the subarachnoid space and cerebrospinal fluid and the rapid acquisition time, make it a useful sequence to include in standard protocols of spinal magnetic resonance imaging.

Myelopathy caused by a histiocytic sarcoma in a cat

An eight-year-old, female spayed, domestic shorthair cat presented with a three-week history of progressive general proprioceptive ataxia and upper motor neuron paresis of the hindlimbs. Computed tomography revealed a mediastinal mass invading the vertebral canal with the T1 spinal nerve and roots, causing extramedullary compression of the cranial thoracic spinal cord. Histopathological and immunohistochemical studies of the mass during postmortem examination disclosed a neoplasm, later determined to be a poorly differentiated histiocytic sarcoma. Feline histiocytic tumours are rare, with only two prior reports existing in the veterinary literature. This report details a case work-up and reviews the literature on feline histiocytic diseases and tumours affecting the feline spinal

Surgical and radiotherapy treatment of a spinal cord ependymoma in a dog

A 4-year-old Beagle dog was presented for investigation of a left pelvic limb gait abnormality. Neurolocalisation indicated a lumbar (L2 to L5) spinal cord lesion. On magnetic resonance imaging (MRI), an intramedullary mass was demonstrated at L3. The mass was partially removed under general anaesthesia and a diagnosis of ependymoma was made on histological examination. The dog was treated with postoperative orthovoltage x-ray radiation (total dose; 44 Gy given in 11 fractions over a 4 week period) combined with low dose carboplatin (25 mg/m2). The dog was alive 16 months after surgery without further neurological deficits. No further tumour growth was detected on subsequent MRI evaluations.

Collie eye anomaly in a mixed-breed dog

A 5-year-old, mixed-breed dog was presented for tetraparesis. Neurologic alterations included a decreased menace response in both eyes. Therefore, an ophthalmic examination was requested. The dog was visual, but menace response, dazzle and pupillary light reflexes were reduced bilaterally. Indirect ophthalmoscopy revealed bilateral optic nerve coloboma and severe choroidal hypoplasia. These lesions closely resembled the ophthalmoscopic features of Collie eye anomaly (CEA). In spite of treatment, the dog's condition worsened and the animal was therefore euthanized. Histology of the globes confirmed severe choroidal hypoplasia and optic disc coloboma in both eyes. The dog was diagnosed to have a lymphoma involving the spinal cord. The two entities were considered not related. As only moderate sight impairment was caused by the posterior segment anomalies, it is by chance that these lesions resembling CEA were found in this mixed-breed dog.

Inflammatory cerebrospinal fluid analysis in cats: clinical diagnosis and outcome

The medical records of 62 cats with clinical signs of central nervous system disease and accompanying inflammatory cerebrospinal fluid (CSF) analysis were examined retrospectively to determine if signalment, clinical signs, CSF analysis and ancillary testing could accurately predict the type of central nervous system disease that was present. An inflammatory CSF was defined as one in which a total nucleated cell count was greater than 5 cells/μl or one in which the total nucleated cell count was normal but the nucleated cell differential count was abnormal. Sex, degree of CSF inflammation, neuroanatomical location and systemic signs provided little contributory information to the final diagnosis. In 63% of the cases a presumptive diagnosis could be made based on a combination of clinical signs, clinicopathological data and ancillary diagnostic tests. CSF analysis alone was useful only in the diagnosis of cats with feline infectious peritonitis, Cryptococcus species infection, lymphoma and trauma. Overall, despite extensive diagnostic evaluation, a specific diagnosis could not be made in 37% of cats. The prognosis for cats with inflammatory CSF was poor with 77% of cats surviving less than 1 year.

SPINAL CORD GLIOMA IN A RIDGE-NOSED RATTLESNAKE (CROTALUS WILLARDI)

An 11-yr-old, female Arizona ridge-nosed rattlesnake (Crotalus willardi) had a 1-yr history of retained egg masses and decreased mobility in the caudal two-thirds of the body. The snake was euthanized when it became unable to right itself. At necropsy, the caudal portion of the spinal cord was found to be enlarged, soft, and translucent pale gray. Microscopically, the caudal portion of the spinal cord was segmentally replaced by a neoplastic mass composed of cells resembling glia (oligodendrocytes and astrocytes). Immunohistochemistry for glial fibrillary acidic protein was positive in the astrocytelike neoplastic cells. The gross, microscopic, and immunohistochemical findings were consistent with a diagnosis of spinal cord glioma. This is the first report of a central nervous system tumor in a reptile.

Prevalence of diseases of the spinal cord of cats

A retrospective review of records of 205 cats with histologically confirmed disease of the spinal cord was performed to identify the prevalence of disease in this nonrandomly selected population of cats. Clinical records were reviewed, and age, duration of neurologic illness, and clinical and histopathologic findings in cats with spinal cord disease were abstracted. Disease processes were classified into 7 categories and 23 groups. The most common diseases affecting the spinal cord of cats were feline infectious peritonitis (FIP), lymphosarcoma (LSA), and neoplasia of the vertebral column secondarily affecting the spinal cord. Information on age, onset and duration of clinical signs, and lesion localization at the postmortem examination in cats belonging to the 7 categories of disease were analyzed to create a practical list of differential diagnoses. Cats were also subcategorized into 3 groups based on their age at death. FIP was the most common disease of cats younger than 2 years of age. LSA and vertebral column neoplasia were the most common diseases affecting cats between 2 and 8 years of age. Vertebral column neoplasia was the most common disease affecting cats older than 8 years of age. Results of this histopathologic study showed that FIP and LSA were the most common disease processes affecting the spinal cord of cats. However, at least 21 other groups of diseases and their relative prevalence were identified.

Spinal nephroblastoma in a crossbreed dog

A three-year-old, male crossbreed dog presented with progressive hindlimb paresis. Magnetic resonance imaging revealed an intramedullary spinal cord lesion of 1.5 cm diameter at the levels of the first and second lumbar vertebrae. Following surgical excision of the mass, there was resolution of the neurological signs. Twelve months later, hindlimb paresis was again evident. A second surgical procedure restored ambulatory status for a further five months before signs recurred and the dog was euthanased. A diagnosis of spinal nephroblastoma was made on the basis of signalment, lesion location and histopathological analysis of biopsy specimens.

Cerebrospinal fluid from a dog with neurologic collapse

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.

Anaplastic Ependymoma in the Cervical Spinal Cord of a Maltese Dog

An 8-year and 6-month-old female Maltese dog showed a stoop with rigidity of her cervix and back. Neurologic examination showed loss of proprioception, and deficiency of pain response. Postmortem examination revealed the neoplastic mass replacing the central area in the cervical spinal cord at the level from 4th to 5th segments. Histologically, the mass was composed of neoplastic ependymal cells. The neoplastic cells showed marked atypism, and occasionally formed ependymal rosettes. Based on the morphologic features, the tumor was diagnosed as anaplastic ependymoma. Immunohistochemistry showed that the neoplastic cells were negative for glial fibrillary acid protein, and slightly positive for vimentin and cytokeratin.

Evaluation of progesterone and estrogen receptor expression in 15 meningiomas of dogs and cats

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.

IMAGING OF A SPINAL NEPHROBLASTOMA IN A DOG

An 8-month-old German Shepherd dog was presented for investigation of pelvic limb gait abnormality. Neurolocalization indicated a T3-L3 spinal cord lesion. The myelographic appearance was of an intramedullary lesion at T9/10, but upon subsequent magnetic resonance imaging it was determined that the mass was extramedullary. A diagnosis of nephroblastoma was made on histological examination. The imaging features of this rare tumor and the differentiation of intradural-extramedullary and intramedullary masses are discussed.

Mixed germ cell tumour of the spinal cord in a young dog

A spinal cord mixed germ cell tumour was identified in a two-year-old, female Airedale terrier with a history of progressive paraplegia. At necropsy, a discrete pale pink spinal cord mass was identified at the L5 vertebra, which extensively invaded the associated spinal cord segments L6 and L7. Histologically, the tumour was located within the subarachnoid space and invaded the spinal cord. It was composed of three different types of cells: small round cells, forming clusters or islands, similar to germ cells identified in testicular germinomas; large cells with eosinophilic or amphophilic cytoplasm, forming trabeculae; and a third, rarer type of well differentiated epithelial cells, forming acinar or tubular structures. Immunohistochemical examination revealed reactivity to antibodies against alpha-fetoprotein and broad spectrum cytokeratins. The composition, cytological features and immunohistochemical staining of this neoplasm are similar to germ cell tumours previously reported in the suprasellar region and in the eye of dogs.

Intramedullary hemangioblastoma in a dog

A 6-year-old male Pointer dog was presented with a 4-week history of progressive hind-limb stiffness. Magnetic resonance imaging demonstrated a focal intramedullary lesion at T1 level with a pattern of ring contrast enhancement. At necropsy, a circumscribed intramedullary reddish-gray tumor was observed. Microscopically, the tumor was composed of thin-walled capillaries lined by endothelial cells and separated by pleomorphic cells (stromal cells) with a moderate degree of anisokaryosis. Immunohistochemically, the endothelial cells were positive for factor VIII-related antigen and the stromal cells were positive for neuron-specific enolase and vimentin. GFAP-positive astrocytes were occasionally observed within the tumor. Both endothelial and stromal cells were negative for synaptophysin, S-100 protein, pankeratin, smooth muscle actin, CD34, CD68, alpha1-antichymotrypsin, and lysozyme. The tumor showed considerable morphologic and immunohistochemical similarities with human hemangioblastoma, and hence the inclusion of this tumor type within the primary neoplasms of the canine central nervous system is suggested.

Secondary chronic respiratory acidosis in a dog following the cervical cord compression by an intradural glioma

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.

Radiographic, computed tomographic and histopathologic appearance of a presumed spinal chordoma in a dog

A 4-year-old Labrador Retriever presented for urinary incontinence and constipation of 2 weeks duration. There was a tender abdomen, lumbar pain and conscious proprioceptive deficits in both pelvic limbs. Depressed pelvic limb reflexes were present consistent with a lower motor neuron lesion. In radiographs of the lumbar spine there was narrowing of the intervertebral disc space at L5-L6 with irregular, multifocal areas of mineralized opacities dorsal to the intervertebral disc space, presumably within the vertebral canal. On computed tomography, an intramedullary, partially mineralized mass was identified in the spinal cord at the level of caudal L5 through cranial L6. At necropsy there was a four-centimeter enlarged, irregular segment of spinal cord at the level of L5-L6. When sectioned, the spinal cord bad a mineralized texture. Histologically there were variable sized cells that were stellate in appearance with vacuolated cytoplasm (physaliferous cells) and mucinous background consistent with a chordoma. Chordoma is a rare, skeletal neoplasm that originates from mesoderm-derived notochord and has been reported in humans and animals. Extraskeletal development of a chordoma within the spinal cord is a rare manifestation of this neoplasm. However, based on other reports in dogs, solitary extraskeletal locations of chordomas may be the typical expression of this neoplasm in the dog. Differentiation of similar histologically appearing tumors, such as a parachordoma or myxoid chondrosarcoma, will require immunohistochemical characterization of these tumors in veterinary patients.

Spinal mast cell tumor in a dog

A 6-year-old, spayed female rottweiler was referred for left forelimb lameness followed by tetraparesis. A mast cell tumor compressing the spinal cord at the level of the sixth cervical to first thoracic (C6-T1) vertebrae was diagnosed based on cervical myelography and necropsy findings. This was considered a primary extracutaneous mast cell tumor, as no evidence of disease was found elsewhere. This is the first report of a primary mast cell tumor in this location.

Dermoid sinus in a golden retriever

A case of dermoid sinus is reported in a golden retriever. The skin lesion was characterised by a fistulous tract in the dorsal cervical region. Surgical dissection revealed a cyst connected by a fibrous cord to the seventh cervical vertebra.

Radiation induced vertebral osteosarcoma following treatment of an intradural extramedullary spinal cord tumor in a dog

A 2-year-old neutered female Rottweiler diagnosed with an intradural extramedullary spinal cord tumor at T12-T13 was successfully treated with cytoreductive surgery followed by Cobalt 60 teletherapy. The dog was euthanised 5-and-a-half years later following diagnosis of an osteosarcoma involving the L1 and L2 vertebrae. Evidence of the initial tumor was not present at necropsy. The vertebral neoplasm fulfilled all of the accepted criteria for a radiation induced tumor. It was concluded that adjunctive irradiation should be considered for treatment of intradural extramedullary tumors of young dogs when total surgical resection is not possible. Although tumor induction is a rare late effect of radiation therapy, the risk of this occurrence should be considered when irradiating young animals. Radiation induced tumors in dogs have been associated with coarse fractionation schemes, or when large intraoperative doses have been administered. A lower dose per fraction, e.g., 3 Gy/fraction or less, is advisable when irradiating young dogs or any dog in which the life expectancy is 3-5 or more years after irradiation.

Spinal cord astrocytoma in a cat

A nine-year-old neutered male domestic shorthaired cat with a history of spinal pain and progressive hindlimb dysfunction was presented to the Norwegian School of Veterinary Science. Following neurological and myelographic examination, an intramedullary mass affecting several lumbar spinal cord segments was diagnosed. A neoplastic lesion was suspected and a poor prognosis was given. On postmortem examination, the spinal cord was found to be dorsally flattened from the 12th thoracic vertebra to the fifth lumbar vertebra and severely thickened with a dorsal cleft from the fifth to the seventh lumbar vertebra. Histologically, the tumour was diagnosed as an anaplastic astrocytoma.

Radiographic diagnosis: cartilaginous exostoses in a dog

A 6 month-old dog was examined for progressive paraparesis. On physical examination bony malformations were palpated over the cranial lumbar vertebral bodies and on the left metatarsal bone. Neuroanatomic lesion localization for the paraparesis was a T3-L3 spinal cord lesion. Radiographs confirmed bony masses at L1-L2 and on the left 3rd metatarsal bone. Magnetic resonance imaging was performed from T3-L3. Severe spinal cord compression was identified at L1-L2. Surgical decompression and biopsy confirmed the mass to be cartilaginous exostoses. This paper is an example of cartilaginous exostoses imaged with MR.

Progressive neurological signs associated with systemic mastocytosis in a dog

A 9-year-old dog was presented with nonregenerative anaemia and severe thrombocytopenia, diarrhoea, spinal hyperalgesia and progressive hindlimb paresis. A moderately well differentiated cutaneous mast cell tumour (MCT) was removed from the skin of the right elbow along with the enlarged right prescapular lymph node. Due to deterioration of the dog's neurological condition, euthanasia was performed. On necropsy examination, haemorrhage and accumulations of poorly differentiated mast cells were found in the lumbosacral region and cauda equina. This article describes an unusual presentation of systemic mastocytosis and the previously unreported finding of metastasis of mast cells to the spinal cord.