Tumours of the Nervous System Flashcards
In the general population the incidence of metastatic cerebral tumour is ________
much higher than that of a primary cerebral neoplasm
What is the common appearance of metastatic brain tumours?
multiple well-delineated spherical nodules that are randomly distributed throughout the brain
List some categories of brain tumours?
- Gliomas
- Meningeal tumours
- Tumours of Nerve Sheath
- Tumours of Neuronal cell types
- Germ cell tumours
- Pituitary gland tumours/ sella lesions
- Haemopoeitic/ lymphomas
List a few characteristics of all gliomas?
They are usually found in the hemispheres, they spread by direct invasion and they rarely metastasise
2 main types of glioma?
Astrocytic or oligodendroglial tumours
What are meningiomas thought to arise from and where are they most commonly found?
Thought to arise from arachnoid granulations so are most commonly found adjacent to venous sinuses
Meningiomas are ____ growing and essentially _______
slow
benign
Two types of tumours of the nerve sheath?
Schwannomas
Neurofibromas
Where are schwannomas derived from?
From the schwann cells surrounding axons
Most common type of schwannoma and location?
Vestibular schwannoma of the CNVIII in the cerebellopontine angle
What symptoms may a vestibular schwannoma cause?
Progressive sensorineural hearing loss, tinnitus and imbalance on ONE SIDE
Schwannomas are ______ but can be difficult to remove because _______
benign
grows around adjacent structures and has an irregular surface
What are neurofibromas derived from?
These are derived from endoneurium which is a layer of delicate connective tissue around the myelin sheath of each nerve fibre in the PNS
Neurofibromas may be solitary or ________ and can affect peripheral nerves over a _______ They can undergo _____ transformation
multiple
wide area or a single group of nerves
malignant
Fully differentiated neurones can neither multiply or ____1_____ Tumours of this type are therefore derived from ____2_____ and seen in _____3______
1) give rise to neoplasms
2) primitive nerve precursors (blast cells)
3) infancy and childhood before completion of differentiation
Medulloblastoma is a primitive nerve cell tumour arising from the _____
cerebellum
Retinoblastoma is a primitive nerve cell tumour arising from the _______
retina
Neuroblastoma and ganglioneuroma is a primitive nerve cell tumour arising from _______
- These are tumours that arise from sympathetic ganglia
* In ganglioneuromas the tumour is derived from blast cells but as the tumour grows the neurons actually mature
How do germ cell tumours usually arise?
Occasionally arise in midline structures and derived from embryologically displaced germ cells
(people can have these misplaced germ cells in their brain their whole life and would only find out if a tumour arose from them)
How can pituitary tumours be classified?
Based on size:
micro adenomas < 1cm
macro adenomas > 1cm
Based on hormone release:
Functioning
Non-Functioning
What type of pituitary tumour may not present?
Non-functioning micro adenoma
Describe presentation of non-functioning pituitary adenomas?
Bitemporal hemianopia Damage to CN III, IV, V and VI Headache Pressure on hypothalamus causing altered appetite, sleep cycle, thirst, precocious puberty and obesity CSF leak Hormone deficiencies
Presentation of prolactinoma?
In women galactorrhea, amenorrhoea and infertility
In men often presents later, impotence, visual field defects, headaches,
Treatment of prolactinoma?
dopamine agonists
cabergoline
bromocriptine
Almost all cases of acromegaly are due to ?
GH secreting pituitary adenoma
Treatment of GH secreting pituitary adenoma?
Trans-sphenoidal surgery is first line
If residual disease offered ocreotide which is a somatostatin analogue
Majority of Cushing’s syndrome is due to?
ACTH secreting pituitary adenoma
Treatment of ACTH secreting pituitary adenoma
Trans-sphenoidal surgery is first line
Metatyrapone (adrenal steroid synthesis inhibitor) may be given to prepare the patient for surgery
List some clinical signs of a brain tumour?
Headache
Papilloedema
Seizures
Neurological signs correlating with areas of brain
Describe some of the ways a brain tumour can cause a headache?
Raised ICP
Invasion/ compression of the dura
Diplopia caused by invasion of CN III, IV, VI
Difficulty focusing due to other effects of tumour
What are some headache red flags that should make you worried about a brain tumour?
Headache that is worse in the morning (because ICP is worse when lying down)
A headache that wakes you up
Headache worse with coughing or leaning forward
Headache associated with vomiting (pressure on medulla)
Define papilloedema?
Bilateral optic disc swelling due to raised ICP
Why are seizures a common presenting feature of brain tumours?
The tumour irritates the cortex and disrupts normal electrical pathways
Describe potential signs/ symptoms may get with frontal lobe involvement of a tumour?
1) Precentral gyrus: Contralateral weakness, the part of the body that the weakness is in will depend on the position along the gyrus, it will correspond with the motor homunculus
2) Broca’s area (inferior frontal gyrus): expressive dysphasia where the patient can still comprehend words but produces faulty sentences
3) Frontal eye fields (Middle frontal gyrus): abnormalities of gaze
4) Micturation inhibition centre: incontinence
5) Personality changes, disinhibition and cognitive slowing
Describe potential signs/ symptoms may get with parietal lobe involvement of a tumour?
1) Postcentral gyrus: contralateral sensory loss, part of body will depend on location along gyrus, it will correspond with the sensory homunculus
2) Contralateral inferior quadrantopia
3) If dominant lobe affected (left in most people): dyscalculia (difficulty understanding maths), dysgraphia (difficulty writing), finger agnosia (inability to distinguish between and recognise all fingers), left-right disorientation
4) If non-dominant lobe affected (right in most people): neglect (deficit in awareness of one side of the body), dressing apraxia (inability to dress yourself automatically), constructional apraxia (inability to build, assemble or draw objects)
Describe potential signs/ symptoms may get with occipital lobe involvement of a tumour?
Visual Cortex: visual hallucinations, contralateral homonymous hemianopia
Describe potential signs/ symptoms may get with temporal lobe involvement of a tumour?
1) Auditory Cortex and Wernickes Area (superior temporal gyrus): damage to auditory cortex can lead to loss of awareness of sound, wernicke’s area is located on the superior temporal gyrus in the dominant hemisphere and damage can lead to receptive dysphasia in which an individual has impaired comprehension and produces jargon (word salad) but their speech is fluent
2) Memory deficits
3) Contralateral superior quadrantopia
Describe potential signs/ symptoms may get with cerebellar involvement of a tumour?
DANISH
• Dysdiadochokinesia: impairment of rapid alternating movements e.g. quick alternating, pronation, supination of the hand
• Ataxia: broad based gait
• Nystagmus: involuntary, uncontrollable eye movements
• Intention tremor: tremor that gets worse as you approach the end point of a guided movement, finger to nose test can show this
• Scanning dysarthria: patients speaks slowly with poor articulation of speech
• Hypotonia: reduced tone
What is the investigation of choice for suspected brain tumours? What may be done instead?
MRI
CT may be done instead if MRI not possible right away
Treatment of low grade astrocytomas?
Removal as has been shown they can de-differentiate into high grade tumours
Gold standard glioblastoma treatment?
surgery, radio and chemo (still poor prognosis)
Treatment of oligodendroglial tumours?
Given a mixture of surgery, chemo and radio
Treatment of meningiomas?
Small meningiomas can just be watched, larger ones may need surgery
Treatment of vestibular schwannomas?
usually not removed unless having big mass effect as surgery risks permanent hearing loss, patient is given a hearing aid
Describe the grades of astrocytic tumours?
Grade 1 Astrocytomas grow very slowly whereas grade 4 cause death within several months and are termed glioblastomas.
Describe growth of oligodendroglial tumours?
They grow very slowly, sometimes over several decade and often show calcification
What are haemangioblastomas?
These are benign, cystic, highly vascular tumours. They develop in the posterior fossa, thus leading to cerebellar dysfunction symptoms as well as symptoms related to raised intracranial pressure.
What are haemangioblastomas usually associated with?
They are most commonly associated with von Hippel–Landau syndrome. This condition is associated with multiple haemangiomas which may be asymptomatic. There is also retinal angiomas, renal cell carcinoma and phaeochromocytoma.
