Brain tumours 2 Flashcards
What is a meningioma ?
- This is a tumour which is attached to the meninges which probably originates from arachnoid granulations
- They account for roughly 20% of primary intracranial tumours
Describe the typical appearance of meningiomas
They are solid, lobulated tumours, well demarcated from the brain tissue into which they project, forming a depression
Where do meningiomas tend to arise ?
- Adjacent to the major venous sinuses, commonly parasagittally or from the base of the skull often in the region of the olfactory groove or the sphenodial ridge
- Also can arise intraventricular
What are the symptoms of meningiomas ?
Symptoms
- Headaches
- If arising in the skull base: cranial nerve neuropathies
- Regional anatomical disturbance
Can some meningomas be malignant ?
- Yes, most are benign (90%)
- Some maligannt can infiltrate overlying bone causing it to be greatly thickened
What preoperative evaluation is required for meningomas ?
CT:
- Homogenous, densely enhancing
- Oedema
- Hyperostosis/ skull ‘blistering’
MRI:
- Dural tail
- Patency of dural sinuses
Angiography +/- Embolisation - Angiography is not generally indicated unless embolization is planned.
- External carotid artery feeders
- Occlusion of sagittal sinus
What is the treatment of meningiomas ?
Small meningiomas: expectant
- Preoperative embolisation
- Surgery
- Radiotherapy
Recurrence – depends on grade and extent of resection
What is a medulloblastoma, where and who does it often occur in?
- It is a poorly differentiated / embryonal tumour (look like primitive undifferentiated embryonal cells) - Primitive blasts that look like undifferentiated embryonic/fetal cells
- It is the 2nd most common CNS tumour in children after pilocytic astrocytoma
- It usually occurs in the midline of the cerebellum
- Medulloblastomas can often block CSF flow and lead to hydrocephalus
Pic shows tumour arising from the cerebellum, occupying the 4th ventricle
What is the treatment of medulloblastomas ?
Surgical resection and radiotherapy - they are very radiosensitive
What is a craniopharyngioma ?
It is a rare benign brain tumour that arises from remnants of Rathke’s pouch (forming near the pituitary gland & hypothalamus)
How are craniopharyngiomas investigated and treated?
- Investigation requires pituitary blood profile and MRI.
- Treatment is typically surgical with or without postoperative radiotherapy.
What specific features are suggestive of a craniopharyngioma ?
- Most commonly occurs in children
- Over 50% present with growth failure
- It may present with hormonal disturbance, symptoms of hydrocephalus or bitemporal hemianopia.
- Adults may present with amenorrhoea, decreased libido, hypothalamic symptoms (DI, sleep disturbance etc) or tumour mass effect
What are the 3 main types of nerve sheath tumours which can arise ?
- Schwannomas (also called neuromas)
- Neurofibromas
- Malignant peripheral nerve sheath tumors (MPST)
Describe what a schwanoma is
- It is a slowly growing, encapsulated tumour from the schwann cells of the cranial, spinal or peripheral nerves
- It commonly affects the vestibular nerve of the vestibulocochlear nerve (vestibular schwanoma/ acoustic neuroma)
What are the signs/ symptoms of acoustic neuromas/ vestibular schwanomas ?
- hearing loss (unilateral)
- tinnitus (hearing sounds that come from inside the body)
- vertigo (the sensation that you’re moving or spinning)
A large acoustic neuroma can also sometimes cause:
- persistent headaches, hydrocephalus and raised ICP
- temporary blurred or double vision Due to CN VI involvement
- numbness, pain or weakness unilaterally due to CN V involvement
- problems with limb co-ordination (ataxia) unilaterally due to cerebellar involvement
- a hoarse voice or difficulty swallowing due to CN IX and X involvement
