10-10-23 - Neuropathology 1 Flashcards
Learning outcomes
- Know the commonest tumours found in the brain, including secondaries from elsewhere
- Describe clinical features of brain tumours
- Understand why grading primary brain cancers is useful
- Know that peripheral nerves can develop tumours too
What is neoplasia?
What is a neoplasm?
What are the 3 general principals of neoplasia?
- Neoplasia is the uncontrolled, abnormal growth of cells or tissues in the body, and the abnormal growth itself is called a neoplasm or tumor.
- 3 general principals of neoplasia:
1) Benign versus malignant (non-invasive vs invasive)
* Implications in brain
2) Malignant: primary versus secondary
* A primary cancer is where a cancer starts. Sometimes cancer cells can break away from the primary cancer and settle and grow in another part of the body. This new cancer growth is called secondary cancer.
3) Non-metastatic/indirect effects
* E.g hormonal
What are the most common tumours in the brain?
What are 6 common primary cancers linked to brain metastases?
What are 3 potential outcomes of metastatic tumours in the brain?
- Commonest tumours in the brain are metastatic (secondary)
- 6 common primary cancers linked to brain metastases:
1) Breast
2) Melanoma
3) Lung
4) Kidney
5) Gut
6) Lymphoma/leukaemia - 3 potential outcomes of metastatic tumours in the brain:
1) Nil
2) Space occupying lesion
* Fits
* Visual
* Drowsiness
* Behavioural change
3) Haemorrhage
What are 3 different types of lung cancers?
Why is it important to know about primary forms of cancer?
What can be used to find a functional lesion?
- 3 different types of lung cancers:
1) Small cell undifferentiated
2) Squamous
3) Adeno - It is important to know about primary forms of cancers as this can give us information on treatment and management
- We might not be able to make a tissue diagnosis from the brain tissue, we may have to be presumptuous
- E.g small cell undifferentiated lung cancer is rapidly growing, but tends to be responsive to chemotherapy
- Functional PET scanning can be useful for determining if we have a functional lesion
Why is it important to know about forms of breast cancer?
- It is important to know about certain forms of breast cancer as BRCA mutations phenotypes that cause breast cancer can make the cancer more likely to spread to the brain
Melanoma (skin cancer picture)
Colorectal cancer picture
What are 9 normal intracranial constituents of the brain?
What can these components give rise to?
- 9 normal intracranial constituents of the brain:
1) Linings – arachnoid membrane
2) Pituitary
3) Peripheral nerve elements (VIII cranial nerve)
4) Neurons
5) Astrocytes – nutrition, support, signalling
6) Microglia – macrophage like
7) Oligodendrocyte – myelin sheath
8) Ependyma – lining of ventricles
9) Choroid plexus – ependyma and capillaries, produce CSF
- Any of these components can give rise to tumours
What is the origin of the most common malignant tumour of the brain?
What are 2 potential types of intracranial primary neoplasms?
Are they cancerous or benign?
What is a type of intracranial peripheral nerve tumours?
What % of primary brain tumours do they make up?
- Most commonly, malignant tumours of the brain are metastatic
- 2 potential types of intracranial primary neoplasms:
1) Meningioma (1/3rd)
* Arise from the meninges of the brain
2) Glioma (1/3rd)
* Arise from the glial (support cells)
- Primary neoplasms are on a malignant spectrum, and can be benign or different severities of malignant
- A type of intracranial peripheral nerve tumour is acoustic Schwannoma (acoustic neuroma) - <10%
Where can meningiomas appear? How do they appear on scans?
How quickly do they grow?
What type of tumours are they?
Are meningiomas invasive?
How can meningiomas affect ICP?
What are 3 symptoms of meningiomas?
What is the treatment for meningiomas?
Why is this?
Why are these tumours easily identified on imaging?
- Meningiomas are sporadic tumours that appear at sites of the arachnoid mater post-irradiation (after radiation treatment)
- They are grossly well demarcated
- They grow slowly
- Meningiomas are Neurofibromatosis type 2 (NF2) tumours
- Meningiomas are not invasive (benign), but erosive and compressive
- The compression from meningiomas can lead to raised ICP, which causes symptoms
- 3 symptoms of meningiomas:
1) Fits
2) Drowsiness
3) Headaches, - The treatment for meningiomas is surgical removal, as radiation may lead to them becoming malignant
- Meningiomas contain calcium, so are easily detectable on imaging
Meningioma histology (in picture)
Are gliomas benign or malignant?
How are they treated?
When can these tumours present?
- Gliomas are effectively all malignant, but are graded
- Since they are invasive, surgical removal is difficult, so we tend to use chemotherapy
- Surgery is possible with continuous sampling of tumour tissue to ensure we aren’t cutting through healthy tissue
- Gliomas can present late
What are 5 different types of gliomas?
Which is the most common type?
- 5 different types of gliomas:
1) Astrocytomas (astrocytes most commonly affected)
2) Oligodendroglioma
3) Ependymoma
4) Choroid plexus tumours
5) Medulloblastoma and PNET
Are gliomas benign or malignant?
What is the role of glioma grading and monitoring molecular changes?
Describe the WHO glioma grading scale
- Effectively all gliomas are malignant, with none being completely benign
- Grading informs prognosis and treatment
- Molecular changes inform prognosis and increasingly treatment options
- WHO glioma grading scale:
1) I Localised
2) II Diffuse (becomes difficult to treat with surgery)
3) III Anaplastic astrocytoma
4) IV Glioblastoma multiforme
Describe Oligodendroglioma (low grade) histology (in picture)
Describe Anaplastic astrocytoma Grade III histology (in picture)
Describe High grade astrocytoma histology (in picture)
What are Primitive neuroectodermal tumours?
What are 2 types of Primitive neuroectodermal tumours?
- Primitive neuroectodermal tumours are tumours that arise in the neuroectoderm (tend to be more peripheral)
- 2 types of Primitive neuroectodermal tumours:
1) PNET
2) Medulloblastoma
Describe how schwannomas form.
How does this affect the nerves?
How do we treat schwannomas?
- Schwannoma (mostly benign) form when a benign proliferation forms in the myelin sheathe formed by Schwann cells
- This tends to grow on the edge of the nerve and forms a benign soft lump
- This can result in nerve fibres being pushed to the side, which can be painful and symptomatic
- Schwannomas can be removed
Describe how neurofibromas form?
Why is it difficult to treat?
- Neurofibromas (benign) form in between nerve fibres when there is a proliferation of cells, resulting in the nerves becoming trapped
- Neurofibromas are difficult to remove, as the nerve may be damaged
What is neurofibromatosis type 1 (NF1)?
What % of NF1 are spontaneous?
What are signs of NF1?
- Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic condition that causes neurofibromas to grow along your nerves
- These can be painful and difficult to deal with
- 50% of cases of NF1 are spontaneous and occur due to a mutation in the NF1 gene
- NF1 presents with lumps, and potentially ‘coffee stains’ on the skin, as growth factors in neurofibromas can stimulate melanocytes
