Intramedullary epidermoid cyst in the thoracic spine of a dog

A 5 yr old female spayed mastiff was evaluated for a 3-4 mo history of paraparesis and 3 days of acutely worse paraparesis and incontinence. On magnetic resonance imaging, a spinal cord lesion was present at the ninth thoracic vertebra. The lesion was hyperintense on T2-weighted images (T2-W), and a hyperintense rim was present on T1-weighted postcontrast images. Histologic examination showed a cystic mass lined by squamous epithelial cells. Histopathologic diagnosis was an intramedullary epidermoid spinal cyst. Epidermoid cyst should be a differential diagnosis in young dogs with a myelopathy and an intramedullary spinal cord lesion on magnetic resonance imaging examination.     

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.     

IMAGING DIAGNOSIS—SPINAL EPIDURAL HEMANGIOSARCOMA IN A DOG

An 8‐year‐old, male Boxer was examined for an acute onset of ambulatory paraparesis. Neurologic examination was consistent with a T3‐L3 myelopathy. Myelography revealed an extradural spinal cord compression in the region of the T10‐T13 vertebrae. On magnetic resonance (MR) imaging, a well‐defined epidural mass lesion was detected. The mass was mildly hyperintense on T1‐weighted, hyperintense on T2‐weighted and STIR images compared to normal spinal cord and enhanced strongly and homogenously. Postmortem examination confirmed a primary epidural hemangiosarcoma. Findings indicated that the MRI characteristics of spinal epidural hemangiosarcoma may mimic other lesions including meningioma and epidural hemorrhages/hematomas of non‐neoplastic etiology.     

Suspected primary glioblastoma multiforme in the canine spinal cord

An eight‐year‐old mixed‐breed dog was presented with progressive paraparesis. Neurological examination revealed a painful diffuse lesion between spinal cord segments T3 and L3. Magnetic resonance images displayed multi‐focal contrast enhancing spinal cord and meningeal lesions. Cytology of these lesions revealed a malignant tumour prompting euthanasia of the dog. Histopathology confirmed the cytological diagnosis and a final diagnosis of a glioblastoma multiforme was made based on immunohistochemistry.     

Paraparesis in a dwarf goat: clarification by means of magnetic resonance imaging

A 4-year old pygmy goat with chronic paraparesis of the hindlimbs was referred to the Ruminant Clinic of the University of Berne. The causative lesion was localized to the thoracolumbar spinal cord after a thorough clinical examination. Because a radiographic examination of the spine had not been diagnostic, magnetic resonance imaging (MRI) was performed. A mass compressing the spinal cord in the region of L2-L5 was detected. The goat was euthanized and autopsied, which allowed for the definitive diagnosis of lymphosarcoma. In addition to the changes in the lumbar area, further neoplastic masses were detected in the region of the thoracic vertebrae, near the thoracic aperture, on the lungs and on the pericardium. However, these processes had not yet caused clinical signs. MRI investigation allowed for the ante mortem diagnosis of an infiltrative mass in the spinal canal of this goat.     

CT and MRI imaging diagnosis of epidural idiopathic sterile pyogranulomatous inflammation in a dog spinal canal

A 12-year-old neutered male shih tzu developed progressive pelvic limb paraparesis. Computed tomography showed a radiolucent mass lesion in the spinal canal at the left side of the 11th thoracic vertebra. The mass was not enhanced by intravenous contrast medium injection. It was hyperintense on both T1- and T2-weighted magnetic resonance images. The signal intensity of the mass was decreased with a fat suppression technique, indicating a fatty origin. After removal of the mass via T11-T12 hemilaminectomy, chronic panniculitis was confirmed by histopathological examination. This case demonstrates the utility of computed tomography and magnetic resonance imaging for the diagnosis of spinal canal pyogranulomatous inflammation.     

Fecal incontinence associated with epidural spinal hematoma and intervertebral disk extrusion in a dog

CASE DESCRIPTION: A 7-year-old castrated male Great Dane was evaluated because of a 2-month history of fecal incontinence. CLINICAL FINDINGS: On the basis of the presence of paraparesis and apparently normal spinal reflexes, the neurologic signs were localized in the region of the third thoracic to the third lumbar spinal cord segments. On the basis of the findings of magnetic resonance imaging, a presumptive diagnosis of a compressive intervertebral disk extrusion with secondary hemorrhage and epidural hematoma formation was made. TREATMENT AND OUTCOME: A right-sided hemil-aminectomy was performed (centered at the T13-L1 intervertebral space) to further characterize the lesion and decompress the spinal cord. The histopathologic diagnosis was extruded intervertebral disk material with chronic hemorrhage and inflammation. Three weeks after surgery, there was complete resolution of the dog's fecal incontinence and moderate improvements in its hind limb function. CLINICAL RELEVANCE: Thoracolumbar spinal cord injuries can result in upper motor neuron fecal incontinence in ambulatory dogs. Epidural spinal hematomas may develop secondary to intervertebral disk herniations and cause spinal cord compression resulting in neurologic deficits.     

IMAGING DIAGNOSIS—SPINAL CORD HISTIOCYTIC SARCOMA IN A DOG

A 12‐year‐old mixed breed dog was presented for evaluation of progressive paraparesis and ataxia. Magnetic resonance (MR) imaging was performed and identified multifocal intradural spinal cord mass lesions. The lesions were hyperintense in T2‐weighted sequences, isointense to mildly hyperintense in T1‐weighted sequences with strong contrast enhancement of the intradural lesions and spinal cord meninges. Spinal cord neoplasia was suspected. A diagnosis of intramedullary spinal cord histiocytic sarcoma, confined to the central nervous system, was confirmed histopathologically. Spinal cord histiocytic sarcoma is a rare neoplasm, but should be included in the differential diagnosis for dogs with clinical signs of myelopathy.     

Spinal meningeal sarcoma in a rottweiler puppy

An 11-week-old rottweiler puppy was presented for evaluation of progressive paraparesis, urinary and faecal incontinence. Radiography and myelography revealed widening of the vertebral canal and remodelling of several lumbar vertebrae associated with an intramedullary spinal mass. Magnetic resonance imaging revealed an extensive, heterogeneous mass involving the lumbosacral spinal cord. Histopathological examination indicated a meningeal sarcoma with very varied cytological architecture.     

Invasive histiocytic sarcoma of the lumbar spine in a ferret (Mustela putorius furo)

This report describes the history, clinical examination and histopathology of a histiocytic sarcoma in a domestic ferret. Clinical signs were acute paraplegia and dysuria. Physical examination revealed a firm, smooth, touch‐sensitive mass in and around the lumbar vertebral column. Neurologic examination was consistent with a lesion between spinal cord segments T3 and L3. Magnetic resonance images revealed bone lesions of L2 and L3 combined with compression of the spinal cord due to a homogenous, isointense mass that was diagnosed as a malignant round cell tumour and the ferret was euthanased. Histopathology confirmed the diagnosis of an infiltrative histiocytic sarcoma.     

Magnetic resonance imaging findings of spinal intramedullary spirocercosis

Spirocerca lupi is a nematode infecting dogs in tropical and subtropical areas. Aberrant S. lupi migration to different body organs, including the spinal cord, has been documented. To date, the diagnosis of aberrant spinal cord migration was made at post-mortem examination or as an incidental finding, during spinal surgery. We describe two dogs with acute asymmetric paraparesis that were subsequently diagnosed with spinal cord spirocercosis. In magnetic resonance (MR) images of the spine, T2 hyperintense lesions were seen in the spinal cord of both dogs. The lesions appeared isointense on T1-weighted images and focal enhancement was detected after gadolinium administration. The MR imaging findings were compatible with focal inflammation, presumably along the parasite migration tract. Gross and microscopic pathologic findings confirmed the diagnosis of aberrant spinal intramedullary migration of S. lupi in one dog, and in the other dog, the clinical and imaging findings were supportive of this diagnosis.     

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.     

Evaluation of a proposed therapeutic protocol in 12 dogs with tentative degenerative myelopathy

The objective of this work was to evaluate the long-term efficacy of a proposed therapeutic protocol in 12 dogs with a tentative diagnosis of degenerative myelopathy, followed-up for a 6-month period. Twelve dogs fulfilling the antemortem inclusion criteria (breed, age, adequate vaccination, history of progressive posterior ataxia and/or paraparesis, no radiographic and myelographic abnormalities in the spinal cord and vertebral column) were allocated. All these dogs presented signs of thoracolumbar syndrome (T3-L3), scored as grade I (mild to moderate ataxia and paraparesis) in 10 and grade II (severe ataxia and ambulatory paraparesis) in 2 cases. Treatment included the use of epsilon-aminocaproic acid and N-acetylcysteine, supplemented with vitamins B, C and E. Prednisolone was given for the first two weeks and upon worsening of neurological signs. Daily exercise, performed as walking or swimming, was strongly recommended. Clinicopathological evaluation was normal in all 12 dogs, and survey radiographs and myelograms did not show spinal cord compression. Magnetic resonance imaging (MRI), performed only in 4 dogs, did not disclose compressive disorders or intramedullary lesions. Neurological signs were progressively worsening in all 12 animals, eventually resulting in severe paraparesis (grade III) or paraplegia (grade IV). The applied medications do not appear to be an attractive alternative to conservative management (physiotherapy) or euthanasia in canine degenerative myelopathy, irrespective of its chronicity.     

Probable lumbar acute non-compressive nucleus pulposus extrusion in a cat with acute onset paraparesis

A spinal cord lesion localised caudal to the L6 spinal segment was diagnosed in a 2-year-old female spayed domestic longhair cat with acute onset paraparesis. Magnetic resonance imaging findings were consistent with an acute, non-compressive nucleus pulposus extrusion of the L5-L6 intervertebral disc. The cat was successfully managed with supportive care, including cage confinement.     

Fibrocartilaginous embolic myelopathy in five cats

Five cats had clinical signs, radiographic findings, and cerebrospinal fluid analyses consistent with fibrocartilaginous embolic myelopathy. All cats had an acute onset of nonpainful, asymmetrical spinal cord signs (paresis or paralysis of one or more limbs). Magnetic resonance imaging was performed in three cats. On T2-weighted images, an intramedullary lesion was revealed that was hyperintense to normal spinal cord gray matter. On T1-weighted images, the lesion was isointense. Three of the cats were euthanized, and postmortem examination confirmed myelomalacia with intralesional fibrocartilaginous emboli. Two cats survived and were clinically improved within 3 weeks.     

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.     

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.     

Meningeal sarcoma mimicking a sciatic neuropathy in a dog

A 5-year-old Golden Retriever presented for lameness evaluation and removal of a dynamic compression plate on the left femur exhibited neurologic signs compatible with a left sciatic peripheral neuropathy. Radiographs revealed a healed fracture of the left femur and a slightly narrowed intervertebral disc space with ventral spondylosis at T_12–13. An EMG demonstrated fibrillation potentials and positive sharp waves in the left hind limb muscles innervated by the peroneal nerve. Surgery was performed to remove the bone plate and explore the left sciatic nerve. The proximal 3 cm of the left peroneal nerve was surrounded by thick fibrous connective tissue and its diameter was smaller than the more distal segment. The dog's condition remained static for 4 weeks and then gradually progressed to paraparesis in 2 weeks. A neurologic examination at that time indicated a caudal lumbar spinal cord lesion and a myelogram confirmed an intradural mass at the level of the 4th lumbar vertebra. The dog was destroyed and a necropsy performed. The histologic diagnosis was meningeal sarcoma.     

MRI findings of haematomyelia in a dog with spontaneous systemic haemorrhage

A 7-year-old female cross-breed dog was brought to Nihon University Animal Medical Center for investigation of tetraplegia. Lameness in the pelvic limbs, that had developed 2 weeks previously, had progressed to tetraplegia. On magnetic resonance imaging of the spinal cord, isointensity was detected from C2 to C4 and T12 to T13, isointensity and hyperintensity were intermingled from L3 to L4, and hyperintensity was detected from L5 to L7 by T1-weighted imaging. On T2-weighted imaging, hyperintensity was detected in all regions described above. The dog recovered from anaesthesia, but died during the day from systemic bleeding as the result of a coagulopathy of unknown aetiology. Histopathological examination revealed haematomyelia in these regions of the spinal cord. This is the first report of magnetic resonance imaging findings of haematomyelia in canine spontaneous systemic haemorrhage. It appeared that the differences in the findings of T1-weighted imaging along the spinal regions reflected time-lags in the occurrence of bleeding.