Chapter 37 Neoplasms of the Vertebrae and Spinal Cord Flashcards
What is the most common clinical signs in dogs?
And cats?
Pain in dogs
Paresis/paralysis in cats
List 10 ddx for vertebral and SC neoplasia
- intervertebral disc herniation
- cervical spondylomyelopathy
- degenerative myelopathy
- degenerative lumbosacral diseasea
- atlantoaxial malformation
- meningomyelitis (infectious or noninfectious)
- discospondylitis
- congenital or developmental malformation
- trauma (vertebral fracture/luxation or brachial plexus trauma/avulsion)
- ischemic myelopathy
What region (cranial to caudal) is the most common location of vetebral/Sc neoplasms in dogs?
Cervical
Order from most to least common:
Extradural
Intradural/extramedullary
Intramedullary
- Extradural (50%)
- Intradural/extramedullary
- Intramedullary
How are radiation adverse effects classified? Describe each classification
Early:
- In proliferating tissues such as epithelium and bone marrow.
- Start during radiation and resolve within weeks.
Late:
- Non-proliferating tissue such as nervous tissue, vascular tissue and bone.
- 6 months to years after radiation.
- Dont resolve i.e. might be life-limiting.
- Include; white matter necrosis, atrophy, haemorrhage/infarction of nervous tissue, chronic progressive myelitis, fibrosis/gliosis, radiation induced secod neoplasms (eg osteosarc reported).
- 5% risk with definitive therapy protocols
What is myokymia, what causes it and how can it be treated.
Myokymia, involuntary muscle contractions resulting in vermiform (rippling) movements of the overlying skin and muscle cramping, may occur as a late side effect to radiation. Regular periodic injections of botulinum toxin into the affected muscle can control the clinical signs.
What is a typical definitive radiation protocol for neoplasia of vertebral column/SC
How does this differ from typical palliative protocol?
Definitive: Daily administration (Monday through Friday) of 18 to 22 treatments (fractions) for a total administered dose of 45 to 54 Gy
Palliative: Dose per fraction is higher but the total dose is lower, typically 16 to 24 Gy
List 4 newer radiation technologies used to increase the dose to the neoplasm and reduce the dose to adjacent tissues
- Intensity modulated radiation therapy
- Tomotherapy
- Stereotactic radiation
- Samarium 153 EDTMP (injectable radioisotope that concentrates in areas of osteoblastic activity. Has been used for palliation of pain due to osteosarcoma and metastatic bone neoplasms in dogs)
List 4 vertebral column/SCneoplasias that liekly to be treated primarily with chemo
- Lymphoma
- Multiple myeloma
- Histiocytic sarcoma complex
- Leukaemias
How do bisphosphonates work?
Induce osteoclast apoptosis
i.e. inhibit bone resorbtion without inhibiting mineralisation.
Why shoudl lymphoma be rules out before giving corticosteroids
May induce remission
Also, dogs with muticentric lymphoma treated with corticosteroids prior to chemo had shorter remission times
What is the most common vertebral neoplasm in dogs?
And cats?
Osteosarc
Also osteosarc
List 10 ddx for primary extradural neoplasia
- Osteosarcoma
- Fibrosarcoma
- Chondrosarcoma
- Haemangiosarcoma
- Lymphoma (can be extradural, intradural/extramedullary or intramedullary!)
- Histiocytic sarcoma complex (can be extradural, intradural/extramedullary or intramedullary!)
- Infiltrative lipoma
- Myxoma/myxosarcoma
- Calcinosis circumscripta
- Osteochondroma
- (Multiple myeloma/single plasma cell tumour)
What arr the two most common couses/sources of secondary extradural neoplasia?
- Epithelial (particularly thyroid or mammary carcinoma)
- Vascular (e.g. haemangiosarcoma)
Descripe radiographic abnormalites.
Top ddx
Lateral radiograph of the lumbar vertebral column of a 6-year-old Labrador Retriever that was presented for acute onset of nonambulatory paraparesis. The lumbar vertebrae have an overall decrease in opacity related in part to the technique; however, there are multiple punctate areas of lysis in the spinous processes (arrows) as well as in the laminae (arrowheads).
Cytological evaluation of the bone marrow was consistent with multiple myeloma.
What is typical appearance of neoplasia on MRI (in terms of intensity on T1W and T2W).
In comparison to normal vertebrae,
- Hypointense on T1-weighted (T1W) images
- Hyperintense on T2-weighted (T2W) images,
- Variability in enhancement after intravenous contrast administration.
How does metastatic rate of skeletal osteosarcoma in cats compare to dogs
Very low metastatic rate in cats
List 5 treatment options for osteosarcoma (individual options which may or may not be combined)
- Surgery
- Chemo
- Palliative radiation
- Definitive radiation
- Bisphosphonates
(radiation recommended due to difficulty in achieving local control)
What is rough survival of dogs with verterbal osteosarc (regardless of therapy)
50 - 150d.
In cats with lymphoma of vertebral column/SC, which is most common location (cranial - caudal) and in temrs of intradural/extramedullay or intramedullary?
Thoracolumbar region
Extradural most common (although infiltration into meninges in 90%! Multiple CNS sites involved in 43% of cases)
Intramedullary rare!
What % of cats with CNS lymphoma have extra-neural involvement?
What are most common sites?
80%
Most commonly kidneys and bone marrow .
i.e. can go looking for dx elsewhere.
What sWHO stage does CNS lymphoma fall into?
Stage 5
How might a presumptive dx of CNS lymphoma be reached?
Cicrulating neoplastic lymphocytes on haem
Or cytology from other organs/CSF
What is typical survival of CNS lymphoma cases with tx?
5-7 months
What does COP and CHOP stand for?
C - Cyclophosphamine
O - Vincristine (“Oncovinc” hence the “O)
P - Pred
C - Cyclophosphamine
H - Doxorubicin (aka “Hydroxydaunorubicin” hence the “H”)
O- Vincristine
P Pred
In which two forms does histiocytic sarcoma complex occur?
In a single tissue/organ or disseminated
What is general MST for histocytic sarcoma (treated in various ways), localised or disseminated anywhere
And for CNS?
MST 3-4 months
Involving CNS MST 3d
How is infiltrative lipoma definitively diagnosed?
Histo with evidence of tissue invasion
How do MRI features of infiltrative lipoma differ from that of myxoma?
What is reported recurrence rate of infiltrative lipoma?
Myxoma is hypointense on T1W
(N.B. both lipoma and myxoma are hyperintense on T2W MRI and both heterogenously contrast enhance)
36 - 50%
Where does myxoma arise from
From synovium.
What are the three classifications of ST mineralisation?
Metastatic: Secondary to abnormal calcium/phosphorous metabolism
Dysptrophic: Normal calcium homeostasis but tissue damaged by pathologocal process
I_diopathic:_ Normal calcium homeostasis with mineralization in normal tissues
What is the typical signalment of animals affected by calcinosis circumscripta?
What is most common anatomical area?
Young (<1 year), large breed dogs, typically GSD
Between dorsal arch of C1 and C2
A, Lateral radiograph of a 1-year-old German Shepherd Dog with a nonpainful, firm, nonmovable mass adjacent to the C6 vertebra. There is a heterogeneously mineralized mass ventral to the vertebral column from the C5 vertebra through C6 vertebra.
B, Postcontrast T1W image in the transverse plane that is fat suppressed using the Dixon technique discloses a strongly and heterogeneously enhancing mass arising from the right transverse process of C6.
C, A CT image at approximately the same level of the C6 vertebra as in panel B. The mass appears as a heterogeneously mineralized. Calcinosis circumscripta was diagnosed based on a percutaneous biopsy.
Describe the imaging abnormalities.
Dx?
A, T2W image in the sagittal plane of the cranial thoracic vertebral column from T1 though T5. Ventral to the spinous process of T4, there is an extradural mass that is compressing the spinal cord (arrow). At the site of maximal compression, there is loss of the signal from the cerebrospinal fluid in the subarachnoid space. The linear signal void that remains present is a chemical shift artifact. Cranial to the lesion, there is a hyperintensity in the spinal cord that is likely vasogenic edema (arrowhead). Microscopically, specimens from the lesion were consistent with an infiltrative lipoma.
B, T2W images in the transverse plane. The lesion is isointense to the fat between tissue planes. The lesion extends from the extravertebral tissues (open arrow) through an enlarged intervertebral foramen (between arrowheads).
C and D, On the T1W image (acquired as fast spin echo sequences), in the sagittal and the transverse planes, the lesion remains hyperintense (arrows), similar to the T2W images suggestive of fat.
E, Providing further support for the lesion being “fatty,” the lesion is a signal void on a short tau inversion recovery (STIR) image (open arrow).
F, Likewise, the lesion is a signal void (open arrow) on T1W images using chemical fat suppression technique images obtained following contrast administration, which confirms its fatty composition.
What is the treatment of calcinosis circumscripta?
(Calcinosis circumscripta is the deposition of calcium usually at bony prominences (i.e., where bone and skin are thinly separated) or in the footpads and mouth.)
Surgical excision
List 2 other names for osteochondroma
Osteochondromatosis
Multiple cartilaginous exostoses
What is proposed aetiology of osteochondroma/osteochondromatosis/multiple cartilaginous exostoses
Migration of chondrocytes from physeal region into the metaphyseal region of bone., where continues cartilage formation occurs, rather than differenctiation into bone
How does feline osteochondromatosis (i.e. the polyostotic version of osteochondroma) differ from canine
- Occurs in (young) adult cats i.e. skeletally mature (v.s immature dogs and for solitary feline osteochondroma usually in older cats)
- No hereditary predisposition
- Any location on any bone (solitary feline osteochondroma usually associated with joint)
- Feline lesions continue to progress beyond skeletal maturity c.f. dogs
- (Associated with FeLV)
What histo feature is used to diagnose osteochondroma?
Cartilaginous cap over cortex of bone
What is the most common primary tumour of the spinal cord in dogs?
And in cats?
Meningioma in dogs
Lymphoma in cats
Whree (cranially to caudally) do canine meningiomas most commonly occur?
Cervical, specifically cranially to C3
What localisation (extradural, intradural/extramedually, intrameduallry) is a ‘golf tee sign’ usually associated with?
Intradural/extramedullary
(i.e. often with meningiomas)
For dogs, what is the subclassification of meningiomas?
Which are most common?
Grade 1 = Benign
Grade 2 = Atypical
Grade 3 = Anaplastic
Grade 3 rare!
What is the typical appearance of meningioma on MRI?
In comparison to the normal spinal cord:
- Iso- to hypointense on T1W images
- Hyperintense on T2W images,
- Strong, uniform contrast enhancement (
- Distinct borders and may demonstrate evidence of a dural tail
A postcontrast T1W image using chemical fat saturation in the sagittal plane of the cervical vertebral column on an 11-year-old Cairn Terrier with tetraparesis and cervical pain. There is an ovoid, well-demarcated, strongly enhancing lesion (arrow) within the cranial aspect of the vertebral foramen at C2. The lesion is just dorsal to the den (open arrowhead) and at the level of the cranial aspect of the spinous process of C2 (arrowhead). Meningioma was diagnosed based on microscopic evaluation of a specimen obtained at surgery.
What is the primary treatment for meningioma?
Surgery (gross resection or cytoreduction)
Radiotherapy reported as only modality in a prospective paper of intracranial and SC meningiomas (Dolera, JAAHA, 2018). 29/39 cases still alove 2 years later. Adjunctive radiotherpay following intracranial meningioma excision also reported.
(durotomy necessary, dont need to close)
What is MST following gross resection of SC meningioma in dogs?
19 months
(+ consider follow up radiation)
What factor was associated with increased rosk of recurrence in dogs with incompletely resected intracranial meningioma?
And with shorter survival?
Increased PCNA index
Increased VEGF expression
What is the preferred term for nerve sheath tumour?
Nerve sheath neoplasm
(subdivided into benign and malignant (malignant more common))
List 2 ddx for nerve sheath neoplasm
Lymphoma, neuritis
What is typical appearance of nerve sheath neoplasm on MRI?
Compared to normal muscle:
- Iso- to hypointense on T1W sequences
- Hyperintense on T2W sequences
- Enhancement patterns may be uniform or heterogeneous.
- Muscle atrophy is typically apparent. As a consequence of neurogenic atrophy, affected muscle may be hyperintense on T2W images and demonstrate diffuse contrast enhancement in comparison to normal muscle.
Describe the image
A transverse plane T2-weighted image of the caudal cervical vertebral column of a 9-year-old West Highland White Terrier that was evaluated for a 6-month history of right thoracic limb lameness. A large, heterogeneous, lobulated mass (asterisk) is seen ventrolateral to the vertebral column. The mass is contiguous with a markedly enlarged C8 spinal nerve (large arrow) in comparison with the normal contralateral spinal nerve (arrowhead). The mass extends proximally along the spinal nerve and into the vertebral canal, causing slight compression of the spinal cord. The intervertebral foramen is subjectively enlarged. A malignant nerve sheath neoplasm was diagnosed on microscopic evaluation.
How might a nerve sheath neoplasm be recognozed on US?
On ultrasound, neoplasms appear as tubular or round hypoechoic structures that cause deviation of the axillary artery from its fellow vein.
How can electrophyiology be used in diagnosis of nerve sheath neoplasm?
Can help localise which nerves affected
Can be used to localise proximo-distal extent of involvememt (epaxial musculature supplied by dorsal branch of spinal nerve. If theres abnormal spontaneous activity in epaxial musculature, proximal spinal nerve/nerve root involvement suggested.
What is tx of choice for nerve sheath neoplasms?
Wide surgical excision
When classifying animals on the basis of location of nerve sheath neoplasms, what is the classification used?
Spinal root, plexus, peripheral
what IHC marker is udes for diagnosis of extrarenal nephroblastoma?
Wilms’ tumour gene product (WT1)
is a marker for human nephroblastoma
What is usual age and breed in extrarenal nephroblastoma cases?
<36 months
GSD
At what level do extrarenal nephroblastomas occur (almost exclusively)
Why?
T10 - L2
(thought to arise from mesonephric or metanephric embryologic remnants that become entrapped in dura/SC)
What are the two types of extrarenal nephroblastoma?
Glandular or solid
In terms of extradural, intradural/extramedullary, intramedullary, where do extrarenal nephroblastoma usually occur?
What is MRI appearance?
Intradural/extramedullary
- Isointense on T1W
- Heterogeneously hyperintense on T2W images.1
- Variable degrees of contrast enhancement
- Concurrent ill-defined hyperintensity of the spinal cord consistent with perilesional edema may be present.
- An intradural/extramedullary myelographic pattern is typically observed; however, as previously mentioned, an intramedullary pattern is possible
T2-weighted MRI of the lumbar vertebral column in the sagittal plane of a 3-year-old mixed-breed dog with a 2-week progressive history of general proprioceptive ataxia/upper motor neuron paraparesis. A single, well-circumscribed lesion is affecting the spinal cord at the level of the L1 vertebra (long arrow). The lesion is isointense compared with the normal spinal cord. Expansion of the caudal and dorsal subarachnoid space is similar to that observed with myelography as a golf tee sign (small arrow). In addition, hyperintensity in the spinal cord extends cranial and caudal to the lesion, consistent with edema (arrowhead). Microscopic evaluation of the lesion disclosed a nephroblastoma.
What is tx for extra-renal nephroblastoma?
Surgery (inc durotomy).
Invasion into Sc common
What is MSt of etra-renal nephroblastoma following sx alone?
1 year
(vs 55d with pred alone)
Re intramedually Sc neoplasia, are primary or secondary lesions more cmmon?
Primary (2/3rds)
What si a clinical exam feature of intrameduallary SC neoplasia
Often painful
List 5 ddx for intramedullary SC neoplasia
- Ependymoma
- Astrocytoma
- Oligodendroglioma
- Undifferentialted glial neoplasms
- Sarcoma
- Haemangioma (Yanke, VetSurg 2019)
- (lymphoma)
- (histiocytic sarcoma complex)
In dogs, what are 3 most common primary intramedually neoplasms?
And most common in cats
sarcoma, astrocytoma, ependymoma
Glial noplasm in cats
What does “drop metastasis” refer to?
Dissemination of choroid plexus carcinoma through CSF pathways
Which neoplasm does not typically display contrast enhancement on T1W?
Glial neoplasms
Which neoplasmsm may be dx on CSF?
Lymphoma or histiocytic sarcoma complex.
How can lymphoma dx be aided?
PARR or flow cytometry
What does PARR (re lymphoma) stand for?
PCR for antigen receptor gene rearrangement.
