Symposium on Clinical Veterinary Oncology
Diagnosis of Spinal Cord Tumors in the Dog Raymond G. Prata, D.V.M.*
Tumors of the spinal column and spinal cord produce pain and weakness of the neck, shoulders, thorax, abdomen, pelvis, and extremities, and these signs can present a most difficult, perplexing, and stimulating clinical problem. These signs are a result of the involvement of a very complex system composed of bony elements, multiple joints including the disc itself, ligaments, muscles, and vital vascular and neural structures. Early diagnosis is often difficult when the only sign is intermittent pain which may be projected to a localized region in the thorax, abdomen, or extremity. When pain is associated with paresis or plegia, however, a spinal cord lesion is immediately suggested. Because of the prevalence of intervertebral disc disease in the dog with its associated pain and/or paresis, many other spinal disorders have been overshadowed and ineffectively treated. The presenting complaints are all similar, if not identical, in the early development of the pathological processes of spinal meningitis, spinal column osteomyelitis, ankylosing spondylitis, congenital spinal disorders, various traumatically induced diseases, vascular diseases of the spinal cord and meninges,IL 13 • 14 neoplasia of the vertebral column and spinal cord,l 2 and intervertebral disc disease. Consequently, differential diagnoses in each individual case are essential in strategically launching an immediate as well as long-term diagnostic and therapeutic attack.
CLASSIFICATION OF TUMORS In discussing tumors of the spinal cord, all tumors which exert pressure on the spinal cord and nerve roots have been included-the *Staff Surgeon, The Animal Medical Center, New York, New York; Diplomate, American College of Veterinary Surgeons
Veterinary Clinics of North America- Vol. 7, No. l, February 1977
165
Table 1.
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Differential Diagnosis of Spinal Cord Tumors*
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EXTRADURAL
INTRADURAL-EXTRAMEDULLARY
INTRAMEDULLARY
Frequencyt
50%
35%
15%
Tumor Types
Primary malignant bone tumors Metastatic tumors to bone and soft tissues Benign bone tumors
Neurofibromas Meningiomas
Gliomas Ependymomas
Rate of growth
Rapid
Slow
Most often slow
Location
Equal distribution: C, T, and L
Neurofibroma: low cervical (C 5 -C"); uncommon·in other locations in dogs Meningioma: equal distribution C, T, and L
Gliomas: low cervical (C 5 -T 1); lower frequency in other locations in dogs Ependymomas: lower frequency in any location in dogs
Earliest clinical sign; days to weeks prior to onset of paresis Results from bone and soft tissue disruption as well as nerve root compression Intense, unrelenting; diffuse over several vertebra! bodies Increased with activity Increased when spine manipulated May be referred to extremity resulting in "lameness" ("root signature") May be referred to thoracic or abdominal cavity
Earliest clinical sign; months to years prior to onset of paresis Results from tumor growing from dorsal root (neurofibroma) or adjacent to dorsal root (meningioma) Intermittent, focal Decreased with activity Increased when spine manipulated May be referred to extremity resulting in "lameness" ("root signature") May be referred to thoracic or abdominal cavity
Most often nonexistent If present, observed late when paresis pronounced Hemorrhage of tumor, if it occurs, produces meningeal pain
Clinical signs Pain
*C =cervical; T = thoracic; L = lumbar; S = sacral. tOur figures comparable to man.
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Table 1. Differential Diagnosis of Spinal Cord Tumors (Continued)
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EXTRADURAL
INTRADURAL- EXTRAMEDULLARY
INTRAMEDULLARY
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Paresis
Sensory loss
Noted within days to weeks of onset of pain Rapid progressive loss of motor function Late clinical sign Observed in nonambulatory state Often demonstrated prior to nonambulatory state if segments of cord involved (C 6 - T 1 or 4-S1 )
Noted within months to years of onset Insidious onset, very slow progressive loss of motor function
Insidious onset Rapid, progressive loss of motor function Peracute paresis if intramedullary hemorrhage
Late clinical sign Observed in nonambulatory state Often demonstrated prior to nonambulatory state if segment of cord involved (C11 -T 1 or L.-S,)
Late clinical sign Observed in nonambulatory state Often demonstrated prior to nonambulatory state if segment of cord involved (C11 -T 1 or L4 -S 1 )
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Sphincter disturbances
Late clinical feature in upper motor neuron lesions; are nonambulatory Early clinical feature in lower motor neuron lesions involving S2 -S 3 segments or cauda equina
Late clinical feature in upper motor neuron lesions; are nonambulatory Early dysfunction would be noted in lower motor neuron lesions involving S,-S,. or cauda equina; however, these are rare
Early clinical feature in upper motor neuron lesions; however, not with frequency reported in man · Early clinical feature in lower motor neuron lesions involving S2 -S 3 or cauda equina
Course
Very acute onset with associated rapid neurological deterioration in 2-6 weeks Rapid tumor growth
Very insidious obscure onset with associated slow progressive deterioration over months to years Slow rate of tumor growth
Insidious onset with rapid progressive deterioration over days to weeks Slo~ rate of tumor growth; displacement of 50-60% of cord; ischemia and edema result in acute crisis
Diagnostics Cerebrospinal Fluid analysis
Elevated protein
Elevated· protein
Elevated protein RBC, WBC if associated hemorrhage; RBC phagocytized Table 1 continued on the following page
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Table 1.
Differential Diagnosis of Spinal Cord Tumors (Continued)
EXTRADURAL
Radiography
Surgical
INTRAMEDULLARY
Plain films usually noncontributory; may observe widened intervertebral foramen with neurofibroma Myelography: "cup" or "golf tee" configuration
Plain films usually noncontributory Myelography: widened cord shadow on all projections
Corticosteroids, muscle relaxants, anti-inflammatory drugs, narcotic and non-narcotic Relieves pain moderately Improves motor strength Short-lived response
Corticosteroids, muscle relaxants, anti-inflammatory drugs, narcotic and non-narcotic analgesics Relieves pain Improves motor strength Pain controlled for months Paresis initially improved with subsequent progressive deterioration
Corticosteroids, muscle relaxants, anti-inflammatory drugs, narcotic and non-narcotic analgesics Improves motor strength Short-lived response and within days progressive deterioration observed
Very limited success with malignant tumors Benign tumors, rewarding
Early diagnosis affords rewarding surgical outcome
Very limited success with present state of art
Primarily destructive with minimal proliferative changes Myelography: dura displaced from bony canal
Therapy Medical
INTRADURAL-EXTRAMEDULLARY
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