Nervous System Flashcards
What are the top 3 primary brain tumours in the dog?
- meningioma (45%)
- glioma (40%)
- choroid plexus tumours (5%)
What are the most common secondary brain tumours in the dog?
- hemangiosarcoma 29-35%
- pituitary tumours 11-25%
- lymphoma 12-20%
- carcinoma 11-20%
The above compromises 77-86% of all secondary brain tumours
Which breeds are predisposed to meningiomas?
Golden, boxers, min Schnauzers, rat terriers
What is the most common intracranial tumour in the cat?
meningioma (>50%)
the majority (70%) of intracranial tumours = primary
What are the most common secondary brain tumours in the cat?
lymphoma 50%
pituitary 30%
How likely will see a dog/cat with seizures?
50% of dogs with forebrain lesions
25% of cats with brain tumours
What clinicals signs are seen with brainstem lesions?
central vestibular dysfunction
What is the most common clinical sign of intracranial lesion in cats?
abnormal behaviour (16-67%)
non-specific signs (lethargy, decreased in appeite) –> 20% of cats with brain tumours (also in dogs with pituitary tumours)
in one study:
73% behavioural/ mentation changes
68% cranial nerve deficits (ex. nystagmus)
59% gait abnormalities
only 11% presented solely for seizures
Characteristics and outcomes for 61 cats that underwent either surgery or stereotactic radiotherapy as treatment for intracranial meningioma (2005–2017). Tichenor et al 2023
How often can cats have multi-focal meningioma?
20%
How often can secondary tumours be detected on staging for dogs with brain tumours?
3-23%, chest or abdomen
but only 8% resulted in a change in treatment
What’s the accuracy of diagnosing brain tumours for dogs based on MRI?
around 70% of dogs, up to 100% for meningioma
What is a feature of glioma on MRI?
ring enhancement
cannot accurately assess the subtypes or grade though
- but one study did find moderate-to-marked contrast enhancement and a ring pattern were present in OG III but not in OG II, indicating that certain MRI features reflect histological grading in dogs (Ampimaque et al 2022)
- oligodendrogliomas were associated with smooth margins and T1-weighted hypointensity compared to astrocytomas and undefined gliomas. They were also more commonly in contact with the ventricles than astrocytomas (Jose-Lopez et al 2021)
Grading of oligodendroglioma in dogs based on magnetic resonance imaging. Amphimaque et al 2022
Clinical features, diagnosis, and survival analysis of dogs with glioma. Jose-Lopez et al 2021
What’s the risk and accuracy for brain biopsy?
with experienced clinicians and imaging guidance, there is ~5% of serious complications and 95% diagnostic yield
- one study with stereotactic biopsy for dogs found >185k platelet count to minimize risk of side effects (hemorrhage) and the incidence of side effects was 27% (transient exacerbation of preexisting neurologic deficits, transient new deficits, or permanent neurologic deficits) – 88% of side effects were transient.
Risk factors for adverse events occurring after recovery from stereotactic brain biopsy in dogs with primary intracranial neoplasia. Shinn et al 2020.
What’s the most common grade of meningioma in the cat? in the dog?
cat = grade I
dog = grade II (~40%), but all grades can invade into the parenchyma
What is the most common type of glioma in the dog and cat?
oligodendroglioma
Can the grade of choroid plexus tumours be assessed on MRI?
yes, based on intraventricular or subarachnoid metastasis
What are the distribution of grades of choroid plexus tumours in dogs?
grade 1 = choroid plexus papilloma - 40%
grade 3 = choroid plexus carcinoma - 60%
grade 2 not reported in the dog
Can CSF differentiate between neoplastic vs non neoplastic?
the CSF is often abnormal but can be difficult to distinguish between neoplastic vs. not
Which tumours can be diagnosed with CSF more readily?
- choroid plexus carcinoma (>80mg/dL of protein)
- LSA, histiocytic sarcoma (52% diagnostic rate according to Rossmeisl et al 2020)
- cats with caudal brainstem oligodendroglioma
What’s the MST for palliative treatment for intracranial tumours?
around 9 weeks
25 weeks if supratentorial
13 weeks if infratentorial
Pituitary = 51 weeks
Which chemotherapies are commonly used for intracranial tumours?
CCNU, temozolomide, hydroxyurea
What’s the MST with CCNU for intracranial tumours?
MST = 93 days
(palliative = 60 days)
What is the MST for VMAT +/- temozolomide?
420 days (with temozolomide)
383 days (without temozolomide)
What’s the outcome for surgery for feline meningioma?
MST > 2 years (23-37 months)
25% recurrence rate (3-69 months)
preferred tx option for cats with supratentorial meningioma