Cerebral disease: neoplasia Flashcards
How frequent are neoplastic diseases of the cerebral cortex
Neoplastic diseases of the cerebral cortex are not common
What are the key epidemiological factors of neoplastic diseases of the cerebral cortex
Most cats tend to be older (mean age 11.3 years)
Most cases caused by primary tumors
- even though tumors of the CNS are mostly benign, their anatomical location results in “biological malignancy” and are life-threatening in most cases
Most frequent cerebral tumors are:
- meningioma 60%
- lymphoma 15%
- pituitary tumors 9%
How could explain the clinical signs due to an intracranial neoplasia
Clinical signs caused by cerebral tumors may be due to:
- the direct effects of the tumor invasion into the nervous tissue
- compression of adjacent structures
- blockage of the flow of CSF causing hydrocephalus
- disruption of cerebral circulation causing cerebral edema
- initiation of cerebral inflammation
All of these mechanisms can lead to elevated intracranial pressure and possible brain herniation
What is the classical clinical progression of intracranial neoplasia
Generally, with slow-growing tumors such as meningiomas, the onset of clinical signs may be subtle and present for weeks, months or even years before diagnosis
The formation of edema or peri-tumoral bleeding may lead to acute deterioration of signs
How frequent are meningiomas in cats
Meningiomas are the most common primary central nervous system tumor in the cat
- they are most frequently observed over the cerebral hemispheres
What is the biological behavior of meningioma
Generally, meningiomas are solitary tumors, although multiple primary meningiomas are reported quite frequently (up to 20% of cases)
They are usually discrete and well encapsulated with a broad base of attachment to the overlying dura mater
What are the key epidemiological factors for meningiomas
Affected cats are usually over six years of age, with the median age in most reported studies being around 12 years
There is a male sex predilection in cats
Domestic shorthair cats seem most commonly affected
What are the clinical signs for meningioma
Clinical signs are often subtle and gradually progressive
Behavioral changes are commonly reported
- affected cats can become lethargic, dull and inactive
- some cats display increased aggression, disorientation, loss of litter box training and increased vocalization
Circling, blindness, seizures and occasionally cranial nerve deficits may be present
How is a diagnosis of meningioma made
Diagnosis is usually achieved by a combination of advanced imaging and histopathology
Meningiomas are broad-based, homogenous contrast-enhancing lesions that are readily observed on CT or MRI imaging
- on MRI, meningiomas often have a characteristic “dural-tail sign”
The skull over the tumor may be thickened and hyperostotic
CSF analysis is never diagnostic for meningioma
What would be your treatment plan for intracranial meningioma
Determining the anatomical location of the meningioma(s)) is vital to plan treatment as well as any concurrent complications such as hydrocephalus
Treatment is via surgical resection
- median survival times of 26 months have been reported
- the ease of surgical removal is greatly influenced by the location of the tumor
Radiation therapy may become more of an option in the future
Adjunctive chemotherapy is not recommended due to the low chance of metastasis
What is the prognosis for a meningioma that is surgically resected
There is a significant and potentially life-threatening risk of post-operative increase in intracranial pressure due to excessive bleeding and cerebral edema
- if the cat survives this period, the surgery is usually associated with an excellent clinical outcome
Recurrence of meningioma tends to occur in approximately 20% of cats
How frequent is lymphoma as an intracranial neoplasia
Lymphoma less commonly affects the brain than the spinal cord or peripheral nerves
Lymphoma affecting the central nervous system may be a primary lesion or may be part of a multi-centric disease
How can you make a diagnosis of intracranial lymphoma
Their appearance on MRI or CT scanning can be variable
CSF analysis may reveal malignant lymphocytes
- their absence does not rule out the diagnosis
What would be the treatment for intracranial lymphoma
Treatment is challenging as most chemotherapeutic agents do not effectively cross the blood-brain barrier
- drugs such as lomustine and cytosine arabinoside may give some effect
Radiation therapy may give some effects
What is the prognosis for intracranial lymphoma
The prognosis is usually considered grave
