Nervous system pathology 5 Flashcards
Describe the two types of tumours
- Primary: arising from CNS cell types
- Secondary or metastatic: colonising the CNS from distant areas of primary growth
Name 3 examples of primary CNS tumours
- Medulloblastoma
- Astrocytoma
- Choroid plexus papilloma
Name 4 examples of secondary/metastatic CNS tumours
- Mammary adenocarcinoma
- Lymphoma
- Haemangiosarcoma
- Melanoma
How does the distributions of primary vs secondary tumours in the CNS differ?
Primary: usually single masses
Secondary: multifocal distribution
Describe the main features and gross appearance of an astrocytoma
- On cut surface, appear firmer than normal parenchyma, whitish and poorly to un-demarcated
- Increasing malignancy (cell atypia, infiltration, mitoses) -> neoangiogenesis (red colour) -> necrosis (malacia)
- Generally arise in the cerebral hemisphere white mater
Describe the histological appearance of an astrocytoma
- Lots of astrocytes
- Immunohistochemistry shows lots of brown which represents astrocytes
Which breeds have a strong susceptibility for oligodendroglioma?
Brachycephalic breeds
Where do oligodendrogliomas mostly occur?
Frontal, temporal and parietal cortex
Describe the gross features of a oligodendroglioma
- Well circumscribed, sharply demarcated, gelatinous (jelly)
- Areas of necrosis, haemorrhage and cystic degeneration are associated with increased malignancy
Describe the histological features of a oligodendroglioma
Honeycomb appearance, small nuclei surrounded by empty halo (lipid dissolution during processing)
Name the tumour arising from the meninges
Meningioma - most common CNS tumour
Describe the gross features of a meningioma
Lobulated, often granular, white to tan with a broad based attachment to the meninges
- Preferentially located in the anterior fossa, more commonly over the cerebral convexities
Describe the histological features of a meningioma
Whorls and streams of spindloid cells associated with moderate amount of vascular stroma.
Cells have undefined cell boundaries, moderate amount of basophilic cytoplasm and oval nucleus. Whorls are often centred on mineralized centres (psammoma bodies)
What are the main features of a choroid plexus papilloma/carcinoma?
- Arising from epithelium of the choroid plexuses
- Mainly in the fourth ventricle
- Papilloma = benign, carcinoma = malignant
Describe the gross appearance of a choroid plexus papilloma/carcinoma?
- Large, granular and rough texture
- In carcinomas, haemorrhages, necrosis and infiltration of the ventricular wall are observed between the cerebellum and the brainstem
What are the main features of an ependymoma?
- Arising from ependyma lining the ventricles
- Frequently associated with obstructive hydrocephalus
- Metastases can occur (by CSF)
Describe the gross appearance of an ependymoma
Large, well-demarcated, tan, solid intraventricular mass (granular texture)
Describe the histological appearance of an ependymoma
Pseudorosettes - perivascular radial arrangement of neoplastic cells around a small blood vessel.
How can a melanoma in the brain be differentiated from a haemangiosarcoma?
Melanoma: less demarcated, entirely flat
Haemangiosarcoma: well demarcated, very firm component, surrounded by fluid
Describe the histological pattern seen for a haemangiosarcoma
- Cells are trying to remake the appearance of the bloodstream
- Heavy proliferation, mitosis
- No cells resemble epithelial cells and the ones present are all different from each other
Describe the histological pattern seen for a melanoma
- Metastasis of a melanoma
- A lot of mitosis
- Some cells are producing melanin
Provide a diagnosis for the following lesion: Spinal cord, Epidural space. Massive infiltration of an abundant population of neoplastic lymphocytes.
Lymphoma, spinal cord metastasis
What is axonal degeneration (Wallerian degeneration)?
Segmental degeneration of axons and myelin caudally to the site of an insult
How does axonal degeneration (Wallerian degeneration) appear histologically?
Formation of multiple spherical enlargements containing swollen axons (spheroids) -> disintegration of myelin -> necrosis -> infiltration of macrophages (digestion chambers) -> proliferation of Schwann cells (repair attempt) -> axonal sprouting (generation of multiple axonal sprouts)
What does Wallerian-like mean?
Term used when the degeneration is not the consequence of focal trauma (ischemia)
What are the consequences of lack of conduction due to axonal degeneration (Wallerian degeneration)
- Denervation atrophy of the effector organ (muscle, in particular)
- Anterograde and retrograde transynaptic neuronal degeneration (chromatolysis)
What are the features of Wallerian degeneration?
Segmental severe enlargement of the myelin sheath with disintegration of the axon and influx of macrophages (digestion chamber)
Name a vascular disease of the PNS
Ileo-aortic thromboembolism
Describe ileo-aortic thromboembolism
- Thrombosis of distal abdominal aorta at the junction with internal and external iliac arteries -> acute ischemic infarction of the peroneal and tibial nerves and muscles
- Associated with valvular endocarditis (cause) and asymmetrical (or symmetrical) cyanoses of the plantar surface (cold and pale)
How does ileo-aortic thromboembolism present clinically?
- Sudden (vascular!) paraparesis or paraplegia with painful hard muscle and lacking of femoral pulse
- Common in cats
Name the specific inflammatory term for the following anatomical locations:
- Spinal ganglia
- Spinal ganglia and related nerves
- Nerves, both cranial and spinal
- Ganglionitis
- Ganglineuritis
- Neuritis
Define neuropraxia trauma
The nerve is structurally intact.
Mechanical contused traumas impaired temporarily the transmission of impulses.
Full recovery will follow
Define axonotmesis trauma
The axon is structurally damaged and interrupted.
The basal lamina (endonevrium) is intact.
The axon can regenerate in month or years, depending on the distance with the effector organ
Define neurotmesis trauma
Entire nerve is truncated, and regeneration will be not effective.
Describe compression of the caudal equina trauma
Associated with stenosis of the lumbosacral spinal canal.
Chronic axonal degeneration will follow
What is dysautonomias?
Neuronal degeneration followed by reactive gliosis/satellitosis
Compare acute and chronic dysautonomia
- Acute: dying within days
* Chronic: long lasting and with frequent remission
Dysautonomia is associated with which animals?
Grazing animals (grass sickness)
Which bacteria is related to Dysautonomia?
Clostridium botulinum type C
How does Dysautonomia affect the GI tract?
- Relative diffuse shortening and blunting of the intestinal villi
- Associated inflammation and superficial accumulation of mucous/haemorrhage and acute inflammation
Describe the histological appearance of acute Dysautonomia
Plexuses contain an elevated number of neurons, many of which exhibit acute degenerative changes (e.g. chromatolysis)
Describe the histological appearance of sub-acute Dysautonomia
Plexuses contain a reduced number of (degenerated) neurons in association with mild to moderate proliferation on non-neuronal elements
Describe the histological appearance of chronic Dysautonomia
Plexuses are difficult to detect, cellularity is severely decreased and there is marked proliferation of non-neuronal elements
Chromatolytic neurones indicate which types of Dysautonomia?
Acute to subacute
A submucosal plexus indicates which type of Dysautonomia?
Chronic
