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| − | ==Neoplasia==
| + | {{toplink |
| − | | + | |backcolour = E0EEEE |
| − | * Particularly affects older animals.
| + | |linkpage = Nervous System - Pathology |
| − | * Signs may occur acutely, or be progressive and reflect
| + | |linktext =Nervous System |
| − | ** The primary parenchymal damage by the tumour
| + | |maplink = Nervous System (Content Map) - Pathology |
| − | ** Sequelae such as haemorrhage or oedema.
| + | |pagetype =Pathology |
| − | | + | }} |
| − | ==Primary==
| + | <br> |
| − | | |
| − | ===Meningioma=== | |
| − | [[Image:meningiomaleftfrontallobe.jpg|thumb|right|150px|Meningioma - left frontal lobe. Image couretsy of BioMed Archive]]
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| − | [[Image:meningiomabrain.jpg|thumb|right|150px|Meningioma. Image couretsy of BioMed Archive]]
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| − | * Meningioma is most frequently seen in cats and dogs, and is the most common primary brain tumour in these species.
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| − | ** Dolicocephalic dog breeds are predisposed. [[Image:meningiomahisto.jpg|thumb|right|150px|Meningioma, histological view. Image couretsy of BioMed Archive]]
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| − | * Tumours arise from arachnoid cap cells ion the arachnoid layer of meninges.
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| − | * Meningiomas are usually benign, and therefore seldom invade. [[Image:meningiomainfiltrating.jpg|thumb|right|150px|Infiltrating meningioma, histological view. Image couretsy of BioMed Archive]]
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| − | ** Spread to the lung has, however, been reported.
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| − | * The main effects of the tumour is due to its action as a compressive, space-occupying lesion.
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| − | * Meningiomas may become mineralised. <br><br>
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| − | <center>
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| − | {| border="1" cellpadding="7"
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| − | !'''Feature'''
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| − | !'''Dog'''
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| − | !'''Cat'''
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| − | |-
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| − | | '''Lesion Number'''
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| − | | Solitary
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| − | | Multiple
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| − | |-
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| − | | '''Infiltration to Cortical Parenchyma'''
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| − | | More infiltrative
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| − | | Less infiltrative
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| − | |- | |
| − | | '''Encapsulation'''
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| − | | Poorly encapsulated
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| − | | Well encapsulated
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| − | |-
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| − | | '''Metastatic Potential'''
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| − | | Low
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| − | | Low
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| − | |}
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| − | </center>
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| − | [http://w3.vet.cornell.edu/nst/nst.asp?Fun=F_KSsrch&kw=MENINGIOMA View images courtesy of Cornell Veterinary Medicine]
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| − | ====Treatment====
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| − | | |
| − | * Chemotherapy
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| − | * Radiation therapy
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| − | * Surigcal resection.
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| − | ** Better results in cats (as encapsulated and clearly distinguished from normal brain).
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| − | *** Survival is 22-27 months following resection.
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| − | | |
| − | ===Glioma===
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| − | | |
| − | * Due to their origin, gliomas are found within the intraaxial neuroxis.
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| − | * Brachycephalic breeds are predisposed.
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| − | * Glial tumours rise from cells of the brain parenchyma.
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| − | ** Astrocytes - '''Astrocytoma'''
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| − | ** Oligodendrocytes - '''Oligodendroglioma'''
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| − | ** Ependymal cells - '''Ependymoma'''
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| − | ** Choroid plexus cells - '''Choroid plexus tumours'''
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| − | | |
| − | ====Astrocytoma====
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| − | [[Image:astrocytomagross.jpg|thumb|right|150px|Astrocytoma. Image courtesy of BioMed Archive]]
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| − | * The most common of the glial tumors
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| − | * Brachycephalic breeds are predisposed.
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| − | ** E.g. boxer, bulldog.
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| − | [[Image:astrocytomahisto.jpg|thumb|right|150px|Astrocytoma: histological view. Image courtesy of BioMed Archive]]
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| − | =====Gross=====
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| − | | |
| − | * Astrocytomas are firm, solid tumours.
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| − | * Colour tends to be grey-white.
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| − | ** This may sometimes be mottled with red due to areas of necrosis and haemorrhage.
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| − | [http://w3.vet.cornell.edu/nst/nst.asp?Fun=F_KSsrch&kw=ASTROCYTOMA View images courtesy of Cornell Veterinary Medicine]
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| − | | |
| − | ====Oligodendroglioma====
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| − | | |
| − | * Oligodendroglioma is most commonly found in dogs.
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| − | * As for astrocytomas, there is a predilection for brachycephalic breeds.
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| − | | |
| − | =====Gross=====
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| − | | |
| − | * Oligodendrogliomas are soft in texture, and often gelatinous.
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| − | * Colour ranges from grey to pink/red.
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| − | | |
| − | [http://w3.vet.cornell.edu/nst/nst.asp?Fun=F_KSsrch&kw=OLIGODENDROGLIOMA View images courtesy of Cornell Veterinary Medicine]
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| − | | |
| − | ====Ependymoma====
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| − | | |
| − | * Ependymomas are found in dogs, cats, [[Alimentary System - Horse Anatomy|horses]] and cattle.
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| − | * They occur mainly in the ventricles.
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| − | ** The lateral ventricle is most often affected.
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| − | * The tumours may spread within the ventricular system via the cerebrospinal fluid.
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| − | * Growth is generally expansile, but it can be invasive and destructive.
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| − | | |
| − | [http://w3.vet.cornell.edu/nst/nst.asp?Fun=F_KSsrch&kw=EPENDYMOMA View images courstesy of Cornell Veterinary Medicine]
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| − | | |
| − | ====Choroid Plexus Tumours====
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| − | | |
| − | * Choroid plexus tumours are rare.
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| − | * They are mainly found in dogs.
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| − | * Choroid plexus tumours are found in areas where the choroid plexus is concentrated, i.e.:
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| − | ** Lateral ventricle
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| − | ** Third ventricle
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| − | ** Fourth ventricle
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| − | ** There is a particular predilection for the fourth ventricle.
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| − | * This association with the ventricular system makes hydrocephalus a common sequelae.
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| − | * The tumours may metastasis via the CSF and ventricular system.
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| − | * Chroid plexus tumourc contain an increased concentration of blood vessels.
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| − | ** Contrast administration may therefore aid in their identification.
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| − | | |
| − | ====Treatment of Gliomas====
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| − | | |
| − | * The usual modes of anti-cancer therapy may be used to tackle gliomas:
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| − | ** Radiation therapy
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| − | ** Chemotherapy
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| − | ** Surgery
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| − | * However, surgery is less ideal as the tumours are located within the parenchyma.
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| − | | |
| − | ==PNETs==
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| − | | |
| − | * PNETs stands for Primitive NeuroEctodermal Tumors.
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| − | * These are tumors of primitive germ cell origin.
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| − | * They are rare.
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| − | | |
| − | ==Secondary==
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| − | | |
| − | * May arise from:
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| − | ** '''Metastasis'''
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| − | *** Numerous tumours of older animals may metastasise to the brain:
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| − | **** Haemangiosarcoma
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| − | **** Lymphoma
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| − | **** Mammary gland carcinomas
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| − | **** Other carcinomas
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| − | *** Tumours which metastasise to the lungs may be more likely to metastasise to the brain.
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| − | *** Incidence is underestimated, as the brain is not routinely examined at necropsy.
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| − | *** The white-grey matter junction is the most frequently affected area.
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| − | *** Brainstem and spinal cord metastasis are less common than forebrain metastasis.
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| − | *** Choroid plexus tumours and ependymomas may metastasise via the CSF.
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| − | ** Extenstion from extraneural sites, e.g.
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| − | *** Skull
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| − | *** Nasal cavity
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| − | **** Signs of extenstion may preced signs of nasal disease.
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| − | *** Frontal sinuses
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| − | | |
| − | | |
| − | [[Category:Central Nervous System - Pathology]]
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| − | [[Category:Neoplasia]]
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