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.