Brain tumours
From Felipedia
The incidence and prevalence of spontaneous intracranial neoplasia in cats is unknown but it is commonly accepted that they are less common than dogs.
Meningioma are the most common intracranial neoplasm in cats, with a frequency of around 60% of all brain tumours[1]. They arise from the arachnoid layer of meninges. Many are multiple meningomas[2]. Lymphoma is the second most common brain tumour of cats, but is usually a secondary metastasis from other organ sites. The location of most intracranial tumours (including non-meningiomas) is supratentorial (above the meninges). Some (about 10%) are infratentorial.
The causes of brain tumours in cats is unknown, with the exception of meningioma in young cats associated with mucopolysaccharidosis I[3]. Metastasis to the brain is relatively uncommon, occuring in just over 5 per cent of cats with brain tumours: primarily pulmonary carcinoma, squamous cell carcinoma, fibrosarcoma, mammary adenocarcinoma and malignant melanoma[4][5].
Neoplasia is more common in older cats (usually >10 years) with a progressive history of neurological signs. Clinical signs are often nonspecific and include vestibular disorders, behaviour changes, locomotor disorders (circling, pacing), lethargy, anorexia, and vomiting. Seizures are a common presenting sign in one quarter of cases[6]. There appears to be no breed or sex predilection with this disease[7].
| Lesion location | Possible clinical signs |
| Prosencephalon | Seizure, behaviour change, altered mental status, circling, pacing, head pressing, head turn, contralateral postural reaction deficits, blindness |
| Brainstem caudal to diencephalon | Altered mental status, circling, head tilt, nystagmus, ataxia, hemiparesis or tetraparesis, postural reaction deficits (contralateral most common, ipsilateral if rostral midbrain), dysphagia, cranial nerve deficits (III-XII possible), irregular respiration |
| Cerebellum | Cerebellar ataxia, truncal ataxia, hypermetria, intention tremors, broad-based stance, ipsilateral menace response deficit with normal vision and palpebral reflex, opisthotonus, vestibular signs |
Although radiographs may be informative to help toward a diagnosis, MRI or CT scans are the preferred diagnostic procedures. CSF is often abnormal but frequently non-diagnostic[8]. Tumor location together with imaging characteristics may help to define the most likely differential diagnosis. Intracranial neoplasms are classified as either primary or secondary; primary neoplasia being more common. Definitive diagnosis is based on the results of biopsy, cytology and histopathology.
Treatment involves surgical resection/debulking, radiotherapy and chemotherapy. Chemotherapy has been limited primarily to lymphomas. Although the majority of intracranial tumours are slow growing, they are usually quite advanced by the time of diagnosis and consequently, the prognosis is guarded[9].
| Tumour type in cats | Predilection site | Pathology | MRI Oedema | MRI Contrast |
| Astrocytoma (Glioma) | Prosencephalon, intra axial | Solitary | Variable | Heterogenous (+/- ring) |
| Choroid plexus tumours (Neuroepithelial) | Intraventricular choroid | Solitary | Minimal | Homogenous |
| Craniopharyngioma | Ventricular (3rd ventricle) | Solitary, 20 hydrocephalus | Unknown | Uniform |
| Ependymoma (Neuroepithelial) | None | Solitary, 20 hydrocephalus | Unknown | Uniform |
| Hamartoma, Lymphoma | None | Solitary or multifocal | Moderate to severe | Usually Homogenous |
| Malformation tumours (Dermoid sinus, teratoma) | Caudal cranial fossa- 4th ventricle | Solitary | Minimal | Homogenous |
| Medulloblastoma (Neuroectodermal) | Diencephalon | Solitary | minimal | Usually homogeous |
| Meningioma | Prosencephalon, spinal cord | Solitary or multiple | Homogenous | |
| Olfactory neuroblastoma (Neuroectodermal) | Nasal cavity, olfactory, bulb/frontal lobe | Solitary; erosion of cribriform plate | Moderate to severe | Heterogenous |
| Oligodendroglioma (Glioma) | Prosencephalon, intra axial | Solitary | Variable | Heterogenous (+/- ring) |
| Pituitary tumours | Diencephalon | Solitary | Minimal | Usually homogenous |
| Paraneoplastic disorders | None | Solitary or multifocal | N/A | N/A |
- ↑ Troxel, MT (2010) Brain tumours: clinical spectrum. In August, JR (Ed): Consultations in feline internal medicine. Vol 6. Elsevier Saunders, Philadelphia. pp: 548
- ↑ Zaki, FA & Hurvitz, AI (1976) Spontaneous neoplasms of the central nervous system of the cat. J Small Anim Pract 17:773
- ↑ Haskins, ME & McGrath, JT (1983) Meningiomas in young cats with mucopolysaccharidosis I. J Neuropathol Exp Neurol 42:664
- ↑ Chenier, S, Quesnel, A & Girard, C (1998) Intracranial teratoma and dermoid cyst in a kitten. J Vet Diagn Invest 10:381
- ↑ Atasever, A & Kul, O (1996) Metastasis of a mammary carcinoma in the central nervous system of a cat. Dtsch Tierarztl Wochenschr 103:472
- ↑ Tomek, A et al (2006) Intracranial neoplasia in 61 cats: localisation, tumour types and seizure patterns. JFMS 8:243
- ↑ Troxel, MT et al (2003) Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001). J Vet Intern Med 17:850
- ↑ Moore, MP et al (1996) Intracranial tumours. Vet Clin North Am Small Anim Pract 26:759
- ↑ August, J.R. (2006). Consultations in feline internal medicine. Elsevier Saunders, Missouri
