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Brain: neoplasia
Introduction
- May be primary or secondary.
- Signs: usually unilateral, giving an asymmetrical picture with contralateral deficits if affecting a cerebral hemisphere, ipsilateral if affecting the brainstem. Secondary effects, eg brain edema and herniation, may cause rapid progression of signs. Higher incidence in older individuals.
- Diagnosis: confirmation of diagnosis is best carried out using computed tomography or MRI scanning.
- Treatment: depends on nature of tumor but may include surgical resection, chemotherapy, radiotherapy and medical control of secondary effects, eg using corticosteroids.
- Prognosis: depends on tumor type and location.
- Distant metastasis of primary intracranial neoplasia (meningioma) is rare.
Print off the owner factsheet Brain tumor or cancer Brain tumor or cancer to give to your client.
Presenting signs
- Unilateral clinical signs, eg circling, proprioceptive defects and some cranial nerve deficit Cranial nerve neuropathy.
- Ataxia Ataxia and behavioral changes.
- Visual deficits.
- Seizures.
Geographic incidence
- 3.5 per 100,000.
Age predisposition
- Older individuals.
- 75% of cats with meningioma >9 years.
- Young individuals.
Cost considerations
- Surgical resection (meningioma in particular amenable to surgery).
- Radiotherapy Radiotherapy.
- Corticosteroids Prednisolone.
- Anticonvulsants.
- Osmotic diuretic, eg mannitol Mannitol.
Special risks
- Collection of cerebrospinal fluid (CSF) samples can predispose brain herniation in cases of increased intracranial pressure.
General anesthesia
- Hypoxia due to seizure activity and compromise of the airway will lead to cytotoxic brain edema and possibly raised intracranial pressure, therefore oxygen supply should be monitored carefully.
Pathogenesis
Etiology
Primary brain tumors
- Meningiomas Meningioma are the most common intracranial neoplasms.
- Glial tumors, eg astrocytoma Astrocytoma, oligodendroglioma, choroid plexus papilloma Brain: neoplasia choroid plexus tumor, ependymoma Brain: ependymoma, medulloblastoma, etc.
Secondary brain tumors
- Local infiltration from, for example, the skull or primary nasal tumors.
- Metastasis from other sites.
- Pituitary adenomas.
Secondary effects
- Brain edema.
- Brain herniation.
Pathophysiology
- Increased pressure.
- Brain herniation Brain: tentorial hernation.
Secondary effects of brain neoplasia
- Tumor may disrupt the blood-brain barrier, causing local accumulation of fluid mostly in the white matter. This vasogenic brain edema may develop rapidly and is the most significant of the secondary effects, giving an acute clinical picture.
- Rigid cranium does not allow expansion of contents (blood, CSF and brain tissue), so brain edema causes an increase in intracranial pressure. Raised intracranial pressure usually leads to brain herniation.
Types of brain herniation
- Subfalcal.
- Caudal transtentorial.
- Foramen magnum (can cause respiratory depression).
- Rostral transtentorial.
Timecourse
- Slow and progressive development of signs, though may present with acute onset or acute deterioration of signs.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- LeCouteur R A (1999) Current concepts in the diagnosis and treatment of brain tumors in dogs and cats. JSAP 40 (9), 411-416 PubMed.
- Gordon L E, Thacher C, Matthiesen D T et al (1994) Results of craniotomy for the treatment of cerebral meningioma in 42 cats. Vet Surg 23 (2), 94-100 PubMed.
- Gallagher J G, Berg J, Knowles K E et al (1993) Prognosis after surgical excision of cerebral meningiomas in cats - 17 cases (1986-1992). JAVMA 203 (10), 1437-1440 PubMed.