Neuro Pathology Flashcards
1
Q
List the 8 unique histopathologic rxns seen in nervous tissue.
A
- Chromatolysis
- Demyelination
- Wallerian degeneration
- Satellitosis
- Neuronophagia
- Perivascular cuffing
- Malacia
- Neuronal inclusion bodies
2
Q
What are pale areas in neuronal cytoplasm due to dispersion of Nissl’s substance are known as?
A
Chromatolysis
3
Q
Which NS cell types can divide?
Implications?
A
Glial cells
(Only these cells can become tumors.
Neurons CANNOT)
4
Q
Distemper virus shows an affinity for which NS cell type?
A
Oligodendrocytes
5
Q
Which supporting cell type produces myelin?
A
Oligodendrocytes
6
Q
Which supporting cell type controls
CSF movement?
A
Astrocytes
7
Q
Which 2 NS cell types may become neoplastic?
A
- Glial cells
- Ependymal cells
8
Q
What condition describes disruption & phagocytic removal of myelin?
Which cells in the PNS can fix this?
A
- Demyelination
- Schwann cells
9
Q
What is the term for destruction of the axon & myelin sheath following trauma or toxic injury?
Where can it regenerate?
A
- Wallerian Degeneration
- PNS
10
Q
What is the term for the accumulation of glial cells around damaged neurons?
Which type of glial cells mainly?
A
- Satellitosis
- Microglia
11
Q
What is the term for MØic phagocytosis
of necrotic neurons?
A
Neuronophagia
12
Q
What is the term for accumulation of polymorphonuclear or mononuclear leukocytes in Virchow-Robin spaces?
A
Perivascular cuffing
13
Q
What type of leukocytes are suppurative?
A
polymorphonuclear
14
Q
What type of leukocytes are non-suppurative?
A
Mononuclear
15
Q
What does malacia refer to?
A
softening & liquefaction of NS tissue from necrosis of neurons & glial cells
16
Q
What do Cowdry Type A inclusion bodies look like?
What virus are they often associated with?
A
- eosinophilic
- usually single & displaced nucleolus
- Herpes virus
17
Q
What do Cowdry Type B inclusion bodies look like ?
What 2 viruses are they associated with?
A
- Eosinophilic
- often multiple & necleolus is NOT displaced
- Polio & Adenovirus
18
Q
What is Cerebral/spinal dural osseous metaplasia (Ossifying pachymeningitis) & who gets it?
A
- ovoid, thin whitish to mottled red metaplastic plates of bone (due to hemopoietic tissue)
- incidental finding in old dogs
19
Q
List the 5 congenital anomalies that are the result of neural tube closure defects (dysraphia).
A
- Anencephaly
- Cerebral aplasia (prosencephalic hypoplasia)
- Meningoencephalocele
- Meningomyelocele
- Hydromyelia
20
Q
Pathogenesis of Anecephaly?
A
- absence of the cerebral hemispheres w/ failure of forebrain fusion
- Medulla & mesencephalon usually still persists
21
Q
Congenital anomalies resulting from injury during the last trimester of gestation are due to what?
A
prominent inflammatory changes
22
Q
List the 2 Neuronal Migration disorders.
A
- Lissencephaly
- Hydrocephalus
23
Q
Pathogensis of Prosencephalic Hypoplasia?
Who gets?
(AKA Cerebral aplasia)
A
- Failure of bilateral seperation of hemispheres resulting in a SINGLE central ventricle
- NO cerebral hemispheres
- Pigs & lambs
24
Q
Pathogensis of Meningoencephalocele?
A
- protrusion of brain & meninges through a defect in the cranium
- almost always median, along suture lines
- associated with crania bifidum
25
Pathogenesis of **Meningomyelocele**?
Who gets?
* protrustion of **Spinal cord & meninges**
* associated with **spina bifida**
* Brachycephalic breeds of dog
* Manx cats
26
Pathogenesis of **Hydromyelia**?
* excess CSF in spinal cord canal
27
Lesions of **Prosencephalic hypoplasia**?
| (Cerebral aplasia)
* absence of cerebral hemispheres
* single central ventricle
* cyclopia → severe cases (pigs & lambs)
* Abscence of telencephalon
28
DDX of Cerebral aplasia?
| (2)
* Anencephaly
* Hydraencephaly
29
Pathogenesis of **Meningocele**?
Who gets?
* protrusion of fluid-filled meninges
* Pigs → inherited
* Cats → Burmese or pregant queens TXed w/ Griseofulvin
30
Etiopathogenesis of **Lissencephaly** (agyria)?
* Lhasa Apso
* absence of 1° gyri → "smooth brain"
* excessively thin cerebral cortex
31
List the 3 different types of **Hydrocephalus**.
* **Internal** → ventricles
* **External** → sub-arachnoid space
* **Communicating** → ventricles + sub-arachnoid space
(where the fluids accumulates)
32
List the 3 animals in which Hydrocephalus is of no clincal signifcance.
* Early fetus
* Aged animals
* Brachycephalic breeds
33
How is **Hydrocephalus *ex vacuo*** different from Hydrocephalus?
due to compensatory enlargement of CSF spaces
## Footnote
**NOT the result of increased CSF pressure**
34
Etiopathogenesis of **Congenital Hydrocephalus**?
* idiopathic & develops during **fetal life**
* associated w/ Malformation
* To due:
* intra-uterine infections
* nutritional deficiency
35
Eitopathogenesis of **Acquired Hydrocephalus**?
* most often internal hydrocephalus → obstructed CSF flow
* Progressive w/ NO cranial malformation
* Sequel to: inflammation, cholesteatoma, neoplasia & parasitic cysts
36
Pathogenesis of **Hydrocephalus**?
* increased production of CSF
* obstruction of CSF flow
* defective absorption of CSF
37
Lesions of Congenital vs. Acquired Hydrocephalus.
TQ
**Congenital**
* Lateral ventricular distention
* enlarged cranium
**Acquired**
* Lateral ventricular distention
* NO cranial malformation
* Pressure atrophy → white matter + cerebral cortex
38
Etiopathogenesis of **Hydranencephaly**?
* **Etiology** → Viral infections
* **Path** → results from severe encephaloclastic (destructive) effects
* **Lesions:**
* Ø cerebral hemispheres
* membranous CSF
* Leptomeninges filled sacs
39
Pathogenesis of **Porencephaly**?
* **Path**:
* less severe case of hydranencephaly
* destructive process in PRENATAL life
* **Lesions**:
* Cysts
* White matter defects of cerebral hemispheres
40
Etiopathogenesis of **Cerebellar Hypoplasia**?
* **Etiology** → Viral or Inherited
* Feline panleukopenia
* BVD
* CHV
* **Path**→ malformation of cerebellum w/ loss of Perkinje & Granular cells
41
Etiopathogenesis of **Syringomyelia**
* **Etiology** → rare, except Weimaraner
* **Path**→malformation of the spinal cord
* tubular cavity (syrinx) that extends over several LUMBAR segments
42
Lesions of **Syringomyelia**
| (3)
* Cysts in central Gray Matter
* NOT lined by ependymal cells
* Weimaraner → hopping gait
43
Pathogenesis of **Abiotrophy**
| (Cerebellar atrophy)
* 1° metabolic defect/degeneration → premature apoptosis
* involves only cerebellar cortex or multisystem
* Non-inflammatory dz.
44
Lesions of **Abiotrophy**
* Loss of Purkinje & Granular cells
* Seen in basal ganglia → caudate nuclei, putamen, olivary nuclei, & substania nigra
45
Give 5 examples of **TSE's** (prion dz) & species they affect.
* Scrapie → small rumis
* BSE → cattle
* FSE → cats (BSE in cats)
* CWD → free ranging deer
* Transmissible mink encephalopathy
46
Lesions of
**Transmissible Spongiform Encephalopathies**
(TSE).
* NO INFLAMMATION!!
* Cytoplasmic vacuoules & astrocytosis
* _+_ Spongiform changes
* PrPSC protein
47
How do you DX **TSE's**?
* Abnormal protein + lesions → OBEX of brainstem
* IHC → before CNS lesions
* 3rd eyelid, tonsils, retropharyngeal LN
48
Etiopathogenesis of **Globoid Cell Leukodystrophy**
(a Lysosomal Storage dz)
* **Etiology** → inherited defect of galactocerebroside-B-galactosidase
* **Path** → Accumulation of Galactocerebroside
* MØs (microglial cells) → Globoid cells
* neurotoxic → CNS signs (@ 2-7 mo. old)
49
Lesions of **Globoid Cell Leukodystrophy**
* WHITE matter becomes gray & soft
* PAS (+) globoid type MØs
50
4 things that can cause **Brainstem Lesions**
* Prions → obex
* Listeriosis → medulla & pons
* Shiga-like toxin from *E. coli*
* Cu deficiency
51
Vit. E deficiency in birds affects what area of the brain?
Cerebellum
52
**Acute Pb toxicity** in **Dogs** affects what 2 regions of the brain?
Cerebrum & Cerebellum
53
Broad etiology of **Malacia**
| (necrosis of CNS tissue)
* Vascular
* Hypoxia
* horse → post anesthesia
* Toxins
* Infections
* Nutritional
54
List the **Toxins** that can cause Malacia and
the form of malacia seen with each.
* Yellow Star Thistle → nigropallidal
* Pb, Salt, Se → poliomyelomalacia
* Moldy corn → leukoencephalomalacia
* HORSE
55
List the 2 **protozoal** infections that cause **malacia**.
* Theileriosis
* Babesiosis
* DOGS
56
What CNS disease is seen in **Sheep** as a result of
***C. perfringens* D** infection?
Focal Symmetrical Encephalomalacia
| (FSE)
57
What 2 **Nutritional deficiencies** lead to malacia?
* Vitamin → cerebral hypoxia
* A, B1, E
* Mineral
* Copper
58
What 4 things cause **Focal Malacia**?
* FSE
* Equine leukoencephalomalacia
* Equine Nigropallidal encephalmalacia (YST toxicity)
* Avian encephalomalacia (Vit E deficiency)
(associated w/ a specific toxin)
59
Susceptibility of cell types to
**Laminar Cortical Necrosis** (due to hypoxia) ?
Neurons \> Oligodendrocytes\>Astrocytes\> Microglia
## Footnote
**(NOAM)**
60
2 things that cause **Cerebrocortical necrosis** (a form of laminar cortical necrosis)
* Chronic Pb poisoning → cattle
* Thiamine deficiency → cats & cattle
61
What causes **Bilateral Polioencephalomalacia**?
(form of laminar cortical necrosis)
Acute Se toxicity→ pigs
62
What are 2 causes of **Polioencephalomalcia**?
* Salt toxicity → pigs
* Thiamine deficiency → cats & cattle
63
Pathogenesis of **Laminar Cortical Necrosis**
Softening of the cerebrocortical GREY matter based on susceptibility of cells to hypoxia.
64
Lesions of **Malacia**
* Acute **→ swollen gyri**
* **Subacute** (2-5 d) & **Chronic** (7-14 d) → Liquefaction
* yellow/green/brown, flat gyri
* brain edema
65
Sequelae of **Malacia**
* **Gitter cells**
* chronic **liquefaction**
66
**Hyperemia** refers to an increase in ______ blood flow & is an ______ process.
* Aterial
* Active
67
**Congestion** referes to an increase in _____ blood flow & is a _____ process.
* Venous
* Passive
68
Give some examples of things that can cause **Ischemia/Hypoxia** in the CNS.
* High systemic BP
* High ICP
* Reperfusion injury
* Leukocyte products
* **Free radicals**
* **Ca2+**
* **L-glutamate (excitotoxin)**
* **Lactic acidosis**
69
Which age group is more resistant to **hypoxia**?
Why?
* Neonates
* lower metabolic activity
* can utilize lactate
* high [ascorbate] may be protective
70
4 things that affect **Cerebral Metabolic Activity**?
* Systemic BP
* Vascular patency
* ICP
* Autoregulation
71
Etiology of CNS Ischemia/Hypoxia in
Horse, Dog & Cat?
* **Horse** → Anesthesia related syndrome
* **Dog** → Fibrocartilaginous Embolic Myelopathy (FCEM)
* **Cat** → Feline Ischemic Encephalopathy due to *Cuterebra*
72
Lesions of CNS **Ischemia**?
* **Generalized** → ischemic encephalopathy
* (necrosis of neurons & glial cells)
* **Localized** → infarcts
73
Sequelae of **Circulatory Distrubances** to the CNS?
(5)
* Neuronal edema
* Swelling
* Contracture
* Cytoplamsmic eosinophilia
* Karyolysis
74
List examples of things that affect the **INTEGRITY** of the BVs and lead to CNS Hemorrhage?
* Viruses → ICH, HC, ASF, MCF
* *Histophilus somni* (bacT)
* Protozoa
* Trauma
75
List some examples of things that affect the **COAGLABILITY** of the blood in the CNS?
* Thrombocytopenia
* DIC
76
Sites of Hemorrhage?
* ICH in dogs → midbrain & medulla
* FSE in sheep → internal capsule, thalamus, pons
* Thiamine deficiency in cats → inferior colluculi
77
What are the possible consequences of
CNS **Hemorrhage**?
* depends on exact location of hemorrhage
* Can act as SOLs → increased ICP
* Local edema
* Internal or external hydrocephalus
* Epilepsy → from organized thrombi & blood clots
78
What is the most important single change that accompanies ALL intracerebral lesions?
What is it's etiology?
**TQ**
* Edema
* increased ICP due to:
* inflammation
* hypoxia
* ischemia
* toxins
79
Differentiate **Localized** Edema of the CNS
from **Generalized** Edema of the CNS.
**Localized**
* SOLs
* Vague outline
* if Chronic → faint yellow discoloration
**Generalized**
* due to systemic conditions
* diffuse inflammation
* Toxemias/Intoxications
80
What can cause **Generalized Edema** of the CNS in **cattle & sheep**?
Cerebrocortical necrosis (CNN)
81
What are the gross lesions of **Intracellular/Cytotoxic Edema**?
* fluid accumlation in the astrocytes (intracellularly)
* NOT moist
* NOT oozy
82
What are the gross lesions seen in **Vasogenic edema**?
* Extracellular accumulation of fluid
* Moist
* Oozy
83
Gross appearance of the brain followin **edema**?
* flat gyri
* shallow sulci
* lipping
84
What is the definition and etiology of **Lipping**?
* herniation of cerebellum through foramen magnum
* Hydrocephalus
* Cerebrum impacted against tentorium
* Compressed brain stem
85
Sequelae of **CNS Edema**?
* Brain sweling
* Brain distortion
* Herniation
* Brain stem injury
86
Etiology of a **Thromboembolism**
* Reduced diameter of arteries entering brain parenchyma
* Jxn of grey & white matter→ capillaries loop back into cortex
87
What is the lesion associated with a **Thromboembolism**?
OCCLUSIVE
| (not ischemic)
88
Give the typical causes of a **Thromboemobolism**
in the various domestic animal species
* **Cat** → Atrial or Aortic thrombosis
* **Dog** → cartilaginous or nucleus pulposis emboli → FCEM
* **Bacterial emboli**
* **Pig** → Erysipelas & Pasteurellosis
* **Horse** → Sleepy foal dz.
* **Ruminants** → Pasteurellosis
* **ALL** → BM emboli after a long bone fx, Septicemias, tumors, etc.
89
Definition of **Meningitis**?
inflammation of meninges
90
Definition of **Pachymeningitis**?
Inflammation of the **Dura mater**
| (outer, white)
91
Definition of **Leptomeningitis**?
Inflammation of **Pia-arachnoid** mater
| (inner, thin)
92
Definition of **Choroiditis**?
Inflammation of the Choroid
93
Definition of **Ependymitis**
Inflammation of the **ependyma**
94
Definition of **Encephalitis**?
Inflammation of the **Brain**
95
Definition of **Myelitis**?
Inflammation of the **Spinal Cord**
96
Definition of **Encephalomyelitis**
Inflammation of the **Brain & Spinal cord**
97
4 Main lesions of CNS **Inflammation?**
* Pronounced vascular response
* Perivascular cuffing (PMN's)
* Neuronal degeneration/death
* Gliosis
98
What etiology of CNS inflammation is typically seen in **cats**?
Infectious Meningoencephalitis
99
What etiology of CNS inflammation is typically seen in **dogs**?
Idiopathic Inflammatory Brain disorders
100
Etiology of **Suppurative/Purulent Inflammation** due to bacterial infections.
(4)
* Thrombotic Meningoencephalitis (TME)
* Listeriosis
* Enterotoxemia → *C. perfringes* type D
* Edema dz → *E. coli*
101
Etiology & lesions of
**Thrombotic Meningoencephalitis**?
* acute *Histophilis somi* infection
* Hemorrhagic foci & infarcts
* **Vasculitis w/ thrombosis** (hallmark) → septic infarction → septicemia
102
Etiology & Lesions of **Listeriosis** in **Adult rumis**?
* *Listeria monocytogenes*
* Encephalitis or meningoencephalitis
* Affinity for brain stem → multifocal microabscesses in medulla & pons
* **Circumscribed collections of mononuclear cells** (hallmark)
103
Etiology & lesions of **Listeriosis** in **Young Rumis** & **monogastrics**?
* *Listeria monocytogenes*
* septicemia
* focal hepatic necrosis
104
Discuss the 2 different morphologic patterns of
**Focal Symmetrical Encephalomalacia** (FSE).
* Hemorrrhage & softening of the basal ganglia → more common
* Lysis & liquefaction of the white matter of the frontal gyri
105
Etiopathogenesis of **Enterotoxemic colibacillosis** (Edema dz) in **Pigs**?
* Shiga-like toxin production by *E. coli*
* toxin → angiopathy → vasculitis → edema
* Bilateral symmetrical necrosis of the brainstem
106
C/S of **Edema Dz**
| (Enterotoxemic Colibacillosis)
* Incoordination
* hind-limb paresis
* tremors
* convulsions
107
List the histological changes & regions affected seen due to **Nonsuppurative (viral) inflammation.**
* Perivascular cuffing → mononuclear cells (lymphocytes & plasma cells)
* Neuronal degeneration
* Gliosis & demyelination of the WHITE matter
* Lympho (_+_ plasma)cytic meningitis
* Inclusion bodies
108
List the lesions associated with **K9 Distemper virus**.
## Footnote
**TQ**
* Demyelination of WHITE matter
* IN inclusion bodies
109
Which virus has **IC inclusion bodies**
(aka Negri bodies)?
RABIES
110
Pathogenesis of
**Granulomatous Meningioencephalitis** (GME)?
* Middle-aged/ small breed dogs (terriers, poodles)
* marked pervascular cuffing
**Forms:**
* **Focal** → chronic, SOLs
* **Mulitfocal/Disseminated** → acute, lower brain stem, cervical SC & meninges → death w/in a wk.
* **Ocular** → acute progressive or static
111
Pathogenesis of **Necrotizing Encephalitis**
(Pug dog encephalitis/**PDE**)?
* Pugs, Maltese, Yorkies & Chihauhuas
* multifocal, necrotic, cavitating lesions
* Lymphocytes predominate
112
**Cerebral Nematodiasis** results in brain hemorrhage, malacia, migratory tracts & SOLs.
Etiology & area affected??
* *Oestrus ovis* → cranial vault
* *Hypoderma bovis* → spinal cord
* *Cuterebra* spp. → brain
113
Etiopathogenesis of
**Feline Ischemic Encephalopathy**?
* *Cuterebra* spp.
* larvae migrate to brain → vascular lesions
* Hemorrhage
* Thrombosis
* Vasculitis
114
Etiopathogenesis of **Sarcocystosis**?
* *Sarcocytis neurona* → EPM
* affects Spinal Cord
* Wallerian degeneration, encephalitis, myelitis, ataxia
115
Lesions of **Toxoplasmosis?**
* Hemorrhage
* Infarcts
* Edema
* Non-suppurative inflammation
116
Etiology & Lesions of **Neosporosis** by species?
* *Neospora caninum*
* **Horse** → Meningioencephalomyelitis
* **Dog** → Polyradiculoneuritis & Polymyositis
* **Cattle** (IH) → Multifocal malacia _+_ abortion
117
List the 3 examples of **Fungal Dz** of the brain & the lesions associated with each.
* **Blastomycosis →** granulomatous
* **Cryptococcosis**
* Dogs → meninges & paranasal sinus
* Cats → nasal cavity & pharynx
* **Phaeohyphomycosis** (*Cladophialophora bantiana*)
* Pyogranulomatous
118
Which animals get **Vitamin B1 (Thiamine) Deficiency**?
* Cat
* Fox
* Mink
* Ruminants
119
Etiology of **Vitamin B1 (Thiamine) Deficiency**?
* Thiaminase in fish
* Bracken fern
* Horsetail
120
Lesions of **Vitamin B1 (Thiamine) Deficiency**?
* **Rumis** → polioencephalomalacia or central cortical necrosis (CNN) → ceberal cortex
* Edema
* Perivascular dilation
* Hemorrhage
* Laminar necrosis
121
Etiology & lesions of **Swayback** in lambs/goats?
* Copper deficiency
* Astrogliosis
* Chromatolysis
* Necrosis (neuronal)
* Degeneration (mylenated axons)
122
Pathogenesis of **Copper deficieny** in lambs/goats?
* affects the GREY & WHITE matter of brain stem & spinal cord
* Delayed onset→ enzootic ataxia
123
**Vitamin E (Tocopheral) deficiency**
causes what 4 things in **chicks**?
* Encephalomalacia
* "Crazy chick dz"
* Exudative diathesis
* Nutritional mm. dystropy
124
Where are the lesions located in
**Vitamin E (Tocopheral) deficiency**?
focal malacia of the cerebellum
125
Lesions seen in **Vitamin A (Retinol) Deficiency**?
* Night blindness
* Optic neuropathy
* Vit. A is required for osteogensis
126
Which areas are specifically affected by
**Equine Nigropallidal Malacia** (YST toxicity)?
Focal necrosis of:
* Pallidus
* Substantia nigra
127
What is the most consistenly important poison in farm animals?
Pb toxicity
128
Lesions of **Pb toxicity** in **Cattle**?
* **Acute** → head pressing, blindness, death 12-24 hrs
* **Chronic** → laminar cerebral cortical necrosis
129
Lesions of **Pb toxicity** in Dogs?
* WHITE matter edema
* neuronal degeneration → cerebrum & cerebellum
130
C/S of **Selenium toxicity** in **Pigs**?
* Walking backwards
* sitting down
131
Pathogenesis & lesions of **Selenium toxicity** in **Pigs**?
* acute paralytic syndrome due to bilateral poliomyeomalacia
* Yellow discoloration & necrosis of GREY matter of Spinal cord
* Wallerian degeneration
132
4 C/S of **Salt toxicity** in pigs?
* Blindness
* Deafness
* Head pressing
* Convulsions
133
**Pathognomonic** lesions of **Salt Toxicity** in Pigs?
* Eosinophilic meningoencephalitis
* Encephalomalacia
* _+_ laminar necrosis of cerebral cortex GREY matter
134
Etiopathogenesis of **Moldy Corn Toxicity**?
* seen in **Horses**
* due to **Fusmonsin B1 toxin** produced by *Fusarium moniliforme* in corn
* Fumonsin B1 disrupts cell membranes → lipid peroxidation → TNF-alpha is produced by MØs → Ø DNA synthesis
135
Lesions associated with **Moldy Corn toxicity** in Horses?
* Leukoencephalomalacia
* Focal necrosis of the WHITE matter in the cerebral hemispheres
136
C/S of **Moldy Corn Toxicity** in horses?
* Weakness
* Drowsiness
* Staggering
* Circling
* Impaired vision
* Pharyngeal paralysis
137
What are the characteristics of a **Coup lesion**?
* Stationary head
* Focal injury
* Hemorrhage @ point of impact
138
What are the characteristics of a **Contre Coup Lesion**?
* Moving head
* Diffuse injury
* Hemorrhage @ OPPOSITE side of point of impact
139
What is the **nucleus pulposus**?
central semisolid mucoid CT
140
What is the **Annulus fibrosus**?
thick zone of fibrous tissue surrounding the nucleus pulposus
141
C/S of **Intervertebral Disc Dz** due to rupture of the Annulus fibrosus?
* Arches back
* Distended abdomen
* Flaccid paraplegia of limbs
142
Sequelae of **Intervertebral Disc Dz**?
Fibrocartilagnious embolic myelopathy
| (FEM)
143
Contrast **Hansen Type I** & **Hansen Type II**
Intervertebral Disc Dz.
**Hansen I**
* acute rupture, multiple disks involved, early degeneration
* Young animals (\< 3 yrs)
* Chondroystrophoid breeds
**Hansen II**
* gradual rupture, less discs involved
* Older animals
* All breeds
144
Etiopathogenesis of **Cervicospinal Arthropathy** (Wobbler's)
in YOUNG horses?
* malalignment & hypermotility of cervical vertebra
* degeneration of cervical articular processes
145
What is the **most common brain tumor**
**of dogs & cats**?
What 2 areas are most often affected?
* Meningioma
* Olfactory bulb or frontal lobe
146
Lesions of **Meningioma**?
* well circumscribed & encapulsated lesions
* streams & whorls of uniform fusiform CT
147
What **brain tumor** is common in
**Brachycephalic breeds**?
**Glial tumors** → astrocytoma & oligodendroglioma
148
Contrast **Astrocytoma** & **Oligdendroglioma**.
**Astrocytoma**
* MOST COMMON
* POORLY demarcated
* solid, greyish-white mass
**Oligodendroglioma**
* less common
* WELL demarcated
* soft, cyst-like lesions
149
List the 2 examples of **Embryonal Tumors**.
* Medulloblastoma
* Ependymoma
150
Diagnosis of **Medulloblastoma**?
| (rare embryonal tumor)
**Rosette** (rose-like) arrangement of cells
151
2 Lesions of **Epedymoma**?
* Large, well demaracted intravascular mass (SOL)
* Hydrocephalus
152
Give 3 examples of
Brain Metastatic (2° Tumors) Tumors that have predilection for the jxn of Grey & White matter.
* Hemangiosarcoma
* Malignant Melanoma
* Adenocarcinoma
153
What is an incidental lesion seen in horses & is NOT a true neoplasm?
Cholesteatoma
154
Pathogenesis & lesions of
**Cholesteatoma** in OLD horses?
* degenerative lesion of the choroid plexus
* granulomatous inflammation w/ cholesterol crystals
* Hydrocephalus
* Location → lateral ventricles
155
What can cause tail paralysis & loss of bladder & rectum sphincter tone?
Neuritis of cauda equina
