Neuropathology 2 Flashcards
Identify the main classifications of tumors.
- Benign versus malignant
* Malignant: primary versus metastatic
Why is the word benign inadequate when talking of benign brain tumors ?
Because although they are benign in terms of cell biology and invasive potential, their clinical features are NOT benign (i.e. may cause compression of the brain, or raised ICP)
Are most malignant brain cancers primary or secondary ?
Most malignant brain cancers are metastases (but often late in the disease when the patient presents with this, so may not become a driving clinical problem, e.g. because patient already dying from primary cancer)
Identify a primary cancer causing brain metastasis where the metastasis may actually occur early.
Identify a primary cancer causing brain metastasis where the metastasis occurs very late.
Breast cancer
Gastric and colorectal cancer can metastasise in very late stage disease (i.e. not clinically significant)
Identify non-metastatic/indirect effects of brain neoplasia.
E.g. tumor in pituitary can result in release of prolactin, and therefore milk-secreting phenotype
Paraneoplastic Syndromes with Endocrine Function:
Malignant tumors may produce diverse peptide hormones whose secretion is not under normal regulatory control.
1) Cushing’s Syndrome: secretion of ACTH by a tumor leads to features of Cushing syndrome
2) Inappropriate Anti-diuresis: Production of ADH by a tumor may cause sodium and water retention to such an extent that it is manifested as water intoxication
Identify commonest primary sites of tumor spreading to brain.
(main ones) • Breast • Melanoma • Lung • Kidney
(minor ones)
• Gut
• Haematopoietic
Which types of breast cancers can metastasise into the brain ?
HER2 negative, GFR positive or negative, estrogen receptor positive or negative
How does renal cancer spread to the brain ?
NOT via lymphatics, but grows along renal vein, into IVC
Identify types of haemoatopoietic tumors which can spread to the brain.
- Leukaemia (if treat systematically, sometimes relapse of leukaemia can occur in the CNS, because BBB means the CNS becomes protected immunological site for residual cancer stem cells to reside)
- Lymphoma
Identify the main clinical effects of metastatic brain tumors.
• Nil (cerebral metastases may not give symptoms initially)
• Space occupying lesion – Raised intracranial pressure – Headache – Fits – Drowsiness – Behavioural change – More specific changes (depending on area of brain affected, e.g. sight disturbances, personality changes if frontal, speech changes)
• Haemorrhage (some patients may present with stroke as a result of hemorrhage, but hemorrhage commonly results from treatment of metastasis)
Identify the main types of lung cancers which may metastasise into brain. Why does the type of primary tumor matter ?
- Especially small cell undifferentiated (because primary neuroendocrine type origin, used to being migratory type cell)
- Squamous
- Adeno
The type matters for treatment
Identify the main features of breast cancer which metastasises into the brain.
Tends to be high grade breast cancer (tends to metastasise more)
Not limited to one subtype (which subtype will determine treatment)
To what extent is the molecular pathology of the tumor in the brain similar to that of the primary (in the case of secondary brain tumors) ?
Molecular pathology of tumor in brain, similar to primary but can get further genetic change (e.g. from melanoma, see black, nodular tumor mass in the brain)
Describe the findings of a brain metastasis arising from a melanoma, on imaging.
Density oedema around it, as it compresses and damages adjacent tissue
Identify the main treatment options for secondary brain cancer.
- Chemotherapy (tumor may have damaged BBB anyway so many chemo drugs will be able to access brain)
- Beam therapy (form of radiation, at very high doses but targeted to avoid damaging adjacent tissue)
- Biological targeting (for tumors with known particular mutation which can be targeted)
- Surgery (can be contemplated)
What is the main risk of treatment for secondary brain cancer ?
Risks of haemorrhage: if result in necrosis of tumor (which we aim for), may damage blood vessels so get secondary haemorrhage. This can result in expansion, osmosis of fluid into blood area, surrounding compression of brain, and raised ICP.
Identify the main intracranial constituents which can give rise to primary brain tumors.
• Linings – arachnoid membrane • Pituitary • Peripheral nerve elements (e.g. VIII cranial nerve) • Neurons • Astrocytes • Microglia • Oligodendroglia • Choroid plexus • Ependyma
Identify the main primary brain tumors, both benign and malignant.
- Intracranial primary (pretty much benign) neoplasm is mengioma
- Primary neoplasms on the malignant spectrum are gliomas
What proportion of primary tumors do mengiomas make up ? Gliomas ?
Meningiomas: 1/3
Gliomas: 2/3
Identify an example of intracranial peripheral nerve tumor. What proportion of primary brain tumors does this account for ? What
Acoustic Schwannoma (acoustic neuroma) <10%
Which cells do gliomas arise from? Are they benign or malignant ?
Astrocytes, microglia, oligodendroglial cells
ALL MALIGNANT (but low grade have little malignant potential, whereas high grade high). Invasive.
To what extent do brain tumors metastasise ?
They typically do not (except one arising in cerebellum)
