Neoplasia of the Nervous System

Question 1

T/F: primary neoplasia of the CNS is rare in animals

Answer 1

true, except in dogs and cats

Question 2

why is the CNS a fairly common site of metastatic neoplasia?

Answer 2

high volume of blood flow

Question 3

what causes clinical signs of neoplasia in the nervous system

Answer 3

compressive or infiltrating effects of space occupying mass
specific clinical signs depend on location of mass

Question 4

what is the most common type of primary intra-axial CNS neoplasia in dogs and cats?

Answer 4

neoplasia of glial cell origin (ie glioma)
more frequent in dogs

Question 5

what are the 2 major types of neoplasia of glial cell origin?

Answer 5

1. astrocytoma
2. oligodendroglioma (most common)

Question 6

what breeds are predisposed to astrocytomas?

Answer 6

brachycephalics

Question 7

astrocytomas in dogs

Answer 7

• brachycephalics
• temporal and piriform lobes
• firm and tan-gray with indistinct boundaries

Question 8

oligodendroglioma in dogs

Answer 8

• brachycephalics predisposed
• cerebrum: olfactory. bulbs, frontal, temporal and piriform lobe
• gelatinous or mucoid texture

Question 9

what is the difference between astrocytoma and oligodendroglioma appearances?

Answer 9

astrocytomas are firm and tan-gray with indistinct boundaries
oligondendrogliomas are well-demarcated with gelatinous or mucoid textures

Question 10

choroid plexus tumors

Answer 10

• rare but mainly dogs, males predisposed
• ventricular location: hydrocephalus: obstructive or increased CSF production
• classified as papillomas, atypical papillomas or carcinomas. bad whichever way they are

Question 11

what are ependymomas?

Answer 11

• look similar to choroid plexus, rare in domestic animals (horses, cats, dogs, cattle etc)
• located in the ventricular system or extraventricular
• sequelae: obstructive (acquired) hydrocephalus
• derived from humans classification: ependymoma, anaplastic (malignant) ependymoma

Question 11

where are choroid plexus tumors located? what do they cause?

Answer 11

ventricular location: cause hydrocephalus

Question 12

where are ependymomas located and what are common sequelae?

Answer 12

located in the ventricular system: lateral and 3rd are most common
- sequela: obstructive (acquired) hydrocephalus

Question 13

what is the most common primary CNS tumor of cats and dogs?

Answer 13

meningioma

Question 14

meningioma

Answer 14

• most common primary CNS tumor in dogs and cats
  dogs: frontal lobes and olfactory bulbs
  cats: usually solitary and supratentoral
  extra-neuronal metastasis is rare and most are benign

Question 15

gross appearance of meningioma

Answer 15

• extra-axial, well-circumscribed
• maybe secondary pressure necrosis of parenchyma
• commonly amenable to surgical excision

Question 16

neoplasms of neuronal or neuroepithelial origin

Answer 16

• olfactory neuroblastoma: esthesioneuroblastoma
• neoplasm derived from neuronal precursor cells in olfactory mucosa
• caudal aspect of nasal cavity

Question 17

embryonal tumors

Answer 17

• thoracocolumbar spinal cord tumor of young dogs (spinal nephroblastoma): most common kidney tumor in chickens and pigs
• intradural and extramedullary
• between T10-L2
• young <1 year large breed dogs

Question 18

signalment for spinal nephroblastomas

Answer 18

• embryonal tumors: thoracolumbar spinal cord tumor of young dogs
• between T10-L2
• young <1 year large breed dogs

Question 19

where do spinal nephroblastomas typically occur on the spinal cord?

Answer 19

T10-L2

Question 20

leukocytic tumors

Answer 20

lymphoma
feline: multicentric lymphoma most common
canine and feline: mostly T cell lymphoma 90%
cattle: bovine leukemia virus associated (intradural and extramedullary

Question 21

what is the classic leukocytic tumor?

Answer 21

cattle! BLV associated
intradural and extramedullary: cauda equina

Question 22

cholesteatoma

Answer 22

cholesterol granuloma: a tumor-like lesion
- 15-20% OLD HORSES
- suspect chronic hemorrhage or congestion/edema of choroid plexus
- usually incidental unless large

Question 23

T/F: cholesteatoma are usually incidental

Answer 23

true

Question 24

are secondary tumors of the CNS more or less common than primary tumors?

Answer 24

less common

Question 25

secondary tumors of the CNS occur in what 2 ways?

Answer 25

1. direct extension: bony tumors of cranium or vertebrae, carcinomas of nasal and paranasal sinuses, ocular tumors 2. hematogenous metastasis: mammary and pulmonary tumors, melanoma, hemangiosarcoma, and multicentric lymphoma

Question 26

what tumors extend by direct extension?

Answer 26

- bony tumors of cranium or vertebrae: osteoma, osteosarcoma, osteochondrosarcoma, multiple myeloma - carcinomas of nasal and paranasal sinuses - ocular tumors