Tumors of the Nervous System - Spinal Cord Flashcards
Incidence of spinal cord tumors ?
The overall incidence in dogs and cats is unknown, but SC tumors appear to be less common than intracranial neoplasms
% of SC tumors that are extradural ? Often arise from ?
Extradural tumors account for approximately 50% of all tumors affecting the SC and frequently arise from the vertebrae.
% of intradural-extramedullary tumors ? Which one is most frequent ?
Intradural-extramedullary (ID-EM) tumors account
for 35% of all tumors, and meningiomas are the most common ID-EM tumor (Fig. 31.6) and also the most common primary spinal cord tumor diagnosed in dogs and cats.
% of intramedullary (IM) tumors ? How many of them affect multiple compartment ?
Approximately 15% of spinal cord neoplasms are intramedullary (IM), although up to one-third of tumors may involve multiple compartments
Most common primary and secondary IM tumors ?
In dogs, ependymomas and gliomas are
the most frequently diagnosed primary IM tumors, and HSA and transitional cell carcinoma are the most common secondary IM tumors.
What is the most frequent spinal cord tumors in cats ? Any particularity ?
Lymphoma is the second most prevalent SC disease of cats and the most common feline SC tumor, although 85% of cases of SC lymphoma in cats are secondary and part of a multicentric process
Role of retroviral infections in cats with CNS lymphoma ?
Older studies report that 80% to 90% of
cats with CNS lymphoma were seropositive for FeLV p27 antigen; a more recent reported indicated that only 56% of cats with CNS lymphoma were infected with FeLV.138,140 This may reflect the decreasing overall prevalence of feline retroviral infections attributable to vaccination and improved management practices, or infer the importance of other factors that contribute to development of CNS lymphomas
Difference between cats with spinal cord LSA versus other SC tumors ?
Cats with lymphoma are typically younger (median 4 years) at diagnosis than cats with other tumor
types affecting the SC (median 9 years).
Breed predispositions in canine spinal cord tumors ? Which SC tumors affect younger dogs ?
Large-breed, older dogs are predisposed to the development of vertebral tumors.129,130 SC tumors such as ependymomas and nephroblastomas are more commonly seen in dogs less than 6 years
old.142,143 Young German shepherd dogs and golden retrievers (<3 years of age) are predisposed to nephroblastoma.142,143 Boxer dogs were overrepresented in one study of intraspinal meningiomas, and both boxers and other brachycephalic breeds are predisposed to tumors of glial origin
Give tumor examples based on Anatomic Location Relative to Spinal Cord
Typical clinical presentation/clinical signs of SC tumors ?
Dogs and cats with SC tumors commonly present for progressive myelopathic signs reflecting the neuroanatomic location of
the tumor with or without evidence of pain. Tumors in ED or ID-EM locations cause clinical signs of neurologic dysfunction, mainly by compression of the spinal cord or nerve roots by the neoplasm (see Fig. 31.6). IM tumors may cause signs of spinal
cord disease by compression, invasion, or destruction of the SC parenchyma, as well as by obstructing CSF flow and inducing
Are IM tumors painful ? Develop
Signs of paraspinal hyperesthesia arise from compression, stretching, inflammation,
or invasion of the meninges, nerve roots, periosteum, or paraspinal musculature. Early reports have described IM tumors as nonpainful because of lack of nociceptors in the parenchyma126,144;
however, in one study that specifically reported on the prevalence of paraspinal hyperpathia, 68% of all dogs with IM tumors displayed paraspinal hyperpathia.135 Development of hyperpathia in association with IM tumors may be a result of altered neurotransmitter modulation association with destruction of the dorsal horn of the gray matter known as syringomyelic syndrome (see Fig.
31.6D–F).135 Another theory postulates that intramedullary mass expansion may lead to stretching of meninges and stimulation of
nociceptive pathways.
Which one has a protacted clinical course ? IM or metastatic SC tumors ?
Primary IM tumors have a protracted clinical course compared with metastatic IM neoplasms
What can cause acute decompensation of SC tumors ?
Acute decompensation can
occur because of pathologic fracture of neoplastic vertebra, hemorrhage in or around the tumor or SC, or necrosis of the tumor
itself
What % of dogs with metastatic SC tumors show signs of SC location rather than primary organ ?
Clinical signs of SC disease, rather than primary organ dysfunction, is a frequent chief complaint for animals with secondary SC tumors, occurring in up to 44% of dogs with metastatic
tumors
Role of x-ray in SC tumors ?
Survey radiographs may identify primary vertebral body tumors (see Fig. 31.5A, E), pathologic fractures, osseous metastases, as well as evidence of concurrent malignancy or disease, but are frequently normal (see Fig. 31.5C).135,145 In cats, radiographically apparent lytic lesions are seen more commonly in nonlymphoid neoplasms
What is the imaging modality of choice for SC tumors ?
As with brain tumors, MRI is the modality of choice for the evaluation of SC tumors.130–131,135,146,147 However, CT myelography can be helpful for determination of the longitudinal and axial
location of many neoplastic lesions.147 Irrespective of the imaging modality used, in some cases it can be difficult to distinguish ID-EM from IM origin masses.
Typical appearance of meningioma on MRI ?
Meningiomas usually appear as focal ID-EM masses, often strongly enhancing on postcontrast
MRI sequences, and frequently demonstrate a dural tail
Typical location of spinal LSA ? Particularity ? What MR sequence is best ?
Although spinal lymphoma is commonly described as
an extradural mass lesion, especially in cats, it is very often a mixed compartment neoplasm in dogs and involves extraneural tissues in both species.77,136–139 Plasma cell tumors and lymphoma both cause
osteolysis, though the latter typically spares the cortex.148 Short tau inversion recovery (STIR) MR sequences have been reported to have the most utility for the detection of vertebral (see Figs. 31.5D,
31.6A) or SC tumors involving multiple compartments.
Most common ED tumors ? What other types have been reported ?
Among ED tumors arising from the vertebra, OSA is the most common followed by CSA and FSA.125,130,133 A variety of ED (often epidural) tumors that often do not involve the vertebra but arise from adipose tissue have also been reported,
including lipomas, infiltrative lipomas, liposarcomas, and myelolipomas. Solitary plasma cell tumors affecting the vertebra are classified as plasmacytomas (see Figs. 31.5A, B) and may precede multiple myeloma
Most common intra-dural/extramedullary tumors ? Any other particular one ?
Meningiomas and nerve
sheath tumors are the two most common ID-EM neoplasms,
with meningiomas predominating. Nephroblastomas also are
predominantly ID-EM tumors, and almost always are found
between T9 and L2 spinal cord segments because of the embryologic origin of the metanephric blastema from which they
arise
Location of nephroblastomas ? Why ?
between T9 and L2 spinal cord segments because of the embryologic origin of the metanephric blastema from which they
arise
IHC for nephroblastomas? % of positives ?
Approximately 80% of canine nephroblastomas
will demonstrate immunoreactivity to WT-1, a human nephroblastoma gene product
% of feline SC LSA with multicentric disease ? % with concurrent brain involvement ?
When lymphoma involves the neuraxis in dogs and cats, it is most often a manifestation of multicentric disease.136,138,139 In cats with SC lymphoma, more than 80% had extraneural organ involvement that commonly included the bone marrow, kidneys, liver, spleen, lymph nodes, and 43% had concurrent brain
involvement
Immunophenotype of SC LSA in dogs and cats ?
Immunophenotypic characterizations of the
vast majority of canine and feline cases of nervous system lymphomas have not been performed, but both B- and T-cell lymphomas have been reported.136,139 In a recent report of canine
lymphoma, the only case of primary CNS lymphoma identified in the patient cohort was restricted to the SC, and was a diffuse large B-cell lymphoma characterized by CD79a staining.136
Among the 36 cases of metastatic canine CNS lymphomas in this series, 55% were B-cell lymphomas and 45% were of T-cell lineage
What tumor is most likely to be seen in CSF analysis ? What % of them? What finding makes it more likely to happen ?
CSF analysis is frequently done in combination with cross-sectional imaging and is a sensitive but nonspecific test that does not usually provide a diagnosis, with the exception of lymphoma. In
68% of dogs with CNS lymphoma in one series, a diagnosis was made using CSF analysis, and a diagnostic CSF was more likely when infiltrative meningeal lesions were seen on MRI
MST for SC tumors with palliative care ?
Palliative treatment of vertebral and SC
tumors rarely results in prolonged STs or satisfactory functional outcomes, with MST ranging from 0 to 105 days
What SC tumors can be effectively treated with chemo ?
Chemotherapy may be used as an effective primary treatment
modality in cases of vertebral plasma cell tumors, multiple
myeloma, or lymphoma.132,138,140 Dogs with vertebral plasmacytomas and multiple myeloma may have favorable and durable
responses to melphalan and prednisone chemotherapy, even in the
face of multiple or diffuse vertebral lesions and signs of moderate
SC dysfunction
RR for SC LSA ? Duration ?
Although there exist numerous reports on SC
lymphoma in dogs in cats, there is limited information on specific chemotherapy protocols used and the results of treatment,
specifically with respect to survival and neurologic functional endpoints.138,140 Six cats with lymphoma treated with a combination of vincristine, cyclophosphamide, and prednisone had a complete
remission rate of 50% and the median duration of remission was 14 weeks
Chemo for vertebral OSA ?
Platinum-based chemotherapeutic agents are often
use as adjunctive treatment in cases of vertebral OSA
MST for spinal meningioma with surgery ?
Meningiomas can be treated effectively with surgery, with or without postoperative RT.131,133 The MSTs for dogs with intraspinal meningioma treated with surgery alone vary widely and range from 6 to 47 months
Which location of meningioma is more tricky for the surgeon ?
Serious surgical adverse events
are more common with treatment of cranial cervical meningiomas
because of compromise of critical respiratory or vascular structures
MST of canine meningioma with sx + RT ?
The addition of postoperative RT in dogs with meningiomas increased the MST to approximately 45 months; dogs
receiving RT took significantly longer to neurologically decline
than dogs that did not, thus delaying the period to clinical deterioration because of local treatment failure
MST of cats with spinal meningioma treated with sx?
In cats with spinal meningiomas treated surgically, reported MSTs are 6 to 17 months
MST of vertebral tumors with mulitmodal treatment ?
Vertebral tumors in dogs and cats are frequently treated with multimodal therapy consisting of surgery, RT, and/or chemotherapy. The long-term prognosis associated with vertebral tumors is guarded, with one study reporting an overall MST of 4.5 months in dogs with a variety of vertebral tumors.129 In this study, the posttreatment neurologic status was the only significant prognostic factor where a nonambulatory status was significantly associated with shorter STs.
Spinal CSA treated with sx ? (2 cases)
Two dogs with CSAs treated with surgery alone both had a recurrence of clinical signs because of imaging confirmed tumor recurrence within 5 months
of surgery
Prognosis for cats with vertebral tumors ?
Cats with malignant vertebral tumors also have a guarded to
poor long-term prognosis with surgical treatment, with a reported
MST of 3.7 months in one study
Best surgical approach ? Comparison with humans ?
The literature indicates that
common contemporary veterinary neurosurgical techniques are generally insufficient to attain the goal of en bloc surgical excision
of vertebral tumors, which is critical to the therapeutic outcome in humans.129,130,133 Thus, although currently largely unexplored in veterinary medicine, aggressive surgical techniques, including
vertebrectomy with vertebral stabilization, will likely become an important component of advancing the surgical treatment of vertebral and SC tumors
Outcome of spinal nephroblastomas with sx ? sx + RT ? Palliative ? Any prognostic factors ?
Dogs with nephroblastomas treated with surgery and RT may also experience improved functional outcomes and STs compared
with those not treated surgically, although reported MSTs vary widely.142,143 In one study, MST for dogs that were not treated surgically was 1 day compared with 71 days for dogs that underwent cytoreductive surgery.142 Another investigation reported that
dogs with nephroblastoma treated with cytoreductive surgery or RT survived longer (MST 374 days) than dogs treated palliatively (MST 55 days).143 Tumors confined to an ID-EM location were associated with superior STs (MST 380 days) than tumors with
IM involvement (MST 140 days).143 As nephroblastoma affects young dogs, the literature suggests that the majority of dogs will
experience life-limiting local tumor recurrence or treatment complications regardless of treatment type
