Neoplasms and Malformations of the CNS

Question 1

Meningioma

Answer 1

Most common CNS tumor (most benign)- cats and dogs
OG in the meninges, close to dura
Grow by expansion compressing

Question 2

Cats with meningioma

Answer 2

Develop tela choroidea of the 3rd ventricle

Question 3

Astrocytoma

Answer 3

Affects brain or SC, common in dogs
Malignant (anaplasia)

Question 4

Oligodendroglioma

Answer 4

Most common in brachy breeds
Well-demarcated or infiltrate parenchyma
Gray to pink/ red, soft hemorr., gelatinous

Question 5

Ependymoma

Answer 5

OG from ependymal cells lining ventricles and central canal
Common in lateral ventricles
Benign or malignant (usually benign and expansile)

Question 6

Medulloblastoma

Answer 6

From primitive cells in the roof of the 4th ventricle → external granular cell layer
Most common in cerebellum of puppies

Question 7

Other names for adenoma of the pars intermedia

Answer 7

Pituitary pars intermedia dysfunction (PPID)/ Equine’s cushings

Question 8

Adenoma of the pars intermedia

Answer 8

Secondary to loss of dopaminergic inhibition by the hypothalamus to the cells of the pars intermedia

Question 9

What does pars intermedia produce?

Answer 9

Prio-opiomelanocortin (POMC) cleaves→ produce MSH, B endorphin and ACTH

Question 10

CS associated with adenoma of the pars intermedia

Answer 10

Hypothalamus compression → hyperhidrosis, hirsutism, disrupted carb metabolism

Question 11

Which tumors commonly metastasize to the brain?

Answer 11

Melanomas
Sarcomas more the carcinomas

Question 12

Cholesterol granuloma (cholesteatoma)

Answer 12

Degenerative lesion of the choroid plexus, related to inflamm. changes of old horses
Cholesterol crystals found
Most often in lateral ventricles

Question 13

Neural tube closure defects

Answer 13

Ancephaly, cranium bifidum and spina bifidum

Question 14

Ancephaly

Answer 14

Absence of the brain
Primarily cerebral hemispheres (prosencephalic hypoplasia)

Question 15

How is ancephaly developed?

Answer 15

Vit. A excess and cyclophosphamide in 1st trimester

Question 16

Meningoencephalocele

Answer 16

Protrusion of brain and meninges through a defect in the cranium (doesn’t close properly)
Cranium bifida: dorsal midline cranial defect

Question 17

How is meningoencephalocele developed?

Answer 17

Cats: griseofulvin in first week of gestation
Pigs and cats: hereditary

Question 18

Spina bifida

Answer 18

Dorsal defect of the vertebral arches from failure of the neural tube and dorsal vertebral arches to close
Cd. spine usually affected

Question 19

Spina Bifida Occulta

Answer 19

Lack of herniation of meninges and SC
Secondary: Meningocele of SC

Question 20

Spina bifida is hereditary in which animal?

Answer 20

Autosomal dominant in Manx cats (Manx syndrome)

Question 21

Amymelia

Answer 21

Absence of the SC, may occur with ancephaly

Question 22

Holoprosencephaly

Answer 22

Failure of bilateral separation of the proencephalic cavity into 2 hemispheres
Cyclopia occurs when severe

Question 23

Teratogenic clyopic effect

Answer 23

When veratrum californium consumed @ day 14 of gestation (ruminants)
Inhibits sonic hedgehog pathway

Question 24

Hydrocephalus

Answer 24

↑ CSF in the ventricles of subarachnoid space of the brain
Congenital or acquired
Lateral and 3rd ventricles most severely affected

Question 25

Noncommunicating hydrocephalus

Answer 25

Internal: fluid within the ventricular system (most common)
External: Fluid in the subarachnoid space

Question 26

Communicating hydrocephalus

Answer 26

Excess fluid in both locations

Question 27

Hydrocephalus ex vacuo

Answer 27

From destruction and loss of cerebral tissues around the lateral ventricles
In stroke or brain injury, senescent degeneration and Alzheimer’s

Question 28

What causes hydrocephalus

Answer 28

↑ production of CSF
Obstruction of the normal CSF flow
Defective absorption of CSF

Question 29

Congenital hydrocephalus

Answer 29

Pups, foals, calves and piglets
Associated with malformation of the cranium

Question 30

Acquired hydrocephalus

Answer 30

Less severe
Usually no malformation in the cranium

Question 31

What causes porencephaly/ hydranencephaly

Answer 31

Akabane dz, BVD, Bluetongue, border dz

Question 32

________________ are the primary cell type in the brain affected by viruses

Answer 32

Neuroblasts

Question 33

Syringomyelia

Answer 33

Tubular cavitation (syrinx) of the SC and separate from the central canal
Not lined by ependymal cells
Weimeraner, Cavalier King Charles Spaniels

Question 34

CS of syrinomyelia

Answer 34

Symmetrical hopping gait
Unable to extend the hindlimbs

Question 35

Hydromelia

Answer 35

Dilation of the central canal of the SC
Lined by ependymal cells
CSF accumulate in this cavity

Question 36

Lissencephaly (agyria)

Answer 36

Absence of gyri and sulci
Arrest or defect in neuronal migration during embryogenesis

Question 37

Which species is Lissencephaly found in?

Answer 37

Normal in rabbits, mice, rats, reptiles and birds
Hereditary in Lhasa Apso

Question 38

Cerebellar Hypoplasia

Answer 38

Effects primarily on the rapidly dividing external germinal layer of the cerebellum
Inoculated in utero or shortly after birth

Question 39

What pestiviruses cause cerebellar hypoplasia

Answer 39

BVDV in calves
Hog Cholera in fetal pigs
Border dz in lambs

Question 40

What causes cerebellar hypoplasia in kittens?

Answer 40

Panleukopenia virus (parvo)