Tumours of the Nervous System Flashcards
What’s the most common extra-axial tumour?
Meningiomas
What are the features of meningiomas?
Usually benign = arise from residual mesenchymal cells in the meninges and produce neurological symptoms by compressing the underlying brain
What are some examples of extra-axial tumours?
Meningiomas, pituitary adenomas, craniopharyngiomas, choroid plexus papilloma, acoustic neuroma
What is the epidemiology of nervous system tumours?
Primary tumours are second most common in children
Account for 2% of cancers diagnosed but commonest cause of cancer death <40
What is the presentation of nervous system tumours?
Progressive neurological deficit = 68%
Headache = 54%
Usually motor weakness = 45%
Seizures = 26%
What is the underlying reason for increased intracranial pressure?
Contribution of mass within rigid closed box (skull)
What are some causes of increased intracranial pressure?
Tumour mass, oedema mass effect, blockage of CSF or haemorrhage
What is the presentation of increased intracranial pressure?
Headaches, vomiting, mental changes and seizures
What are some features of tumour headaches?
May occur with or without raised ICP
Worse in morning = red flag if it wakes them up
Worse with coughing or leaning forward
May be associated or worse with vomiting
What may a tumour headache mimic?
Tension headache or migraine
What are some causes of tumour headaches?
Raised ICP
Invasion/compression of dura, BV or periosteum
Secondary to diplopia or difficulty focusing
Extreme hypertension
Psychogenic
What investigations can be done for tumours?
CT, MRI, lumbar puncture, PET scan, lesion biopsy, EEG, evoked potentials, angiograms, radionucleotide studies
What cell types are found in neuroepithelial tissue?
Astrocytes, oligodendroglial cells, ependymal cells, neuronal cells, pineal cells, embryonic
What is the most common origin of neuroepithelial tumours?
Astrocytes = account for 60% of tumours, 2/3 or which are high grade
What cell types do glial tumours arise from?
Astrocytes or olidodendrocytes
What is the grading of astrocytic tumours?
I = pilocytic, pleomorphic xanthoastrocytoma, subependymal giant cell II = low grade astrocytoma III = anaplastic astrocytoma IV = glioblastoma multiforme
What indicates the presence of a glioblastoma multiforme?
The presence of necrosis
How do low grade astroglial tumours grow?
Slowly = have malignant potential
What are some features of grade I astrocytomas?
Truly benign = slow growing
Usually children and young adults
Surgery is first line and curative
Where do pilocytic astrocytomas occur?
In the optic nerve, cerebellum or brainstem
What are the types of low grade astrocytomas?
Fibrillary, gemistocytic and protoplasmic
What are the features of low grade astrocytomas?
Hypercellularity, gemistocytic, vascular proliferation and necrosis
Where do low grade astrocytomas commonly occur?
Temporal, posterior frontal and anterior parietal lobes
How do low grade astrocytomas present?
Seizures
What are poor prognostic features for low grade astrocytomas?
Age > 50, focal deficit, short symptom duration, raised ICP, altered consciousness, enhancement on contrast studies
What is the treatment for grade II astrocytomas?
Surgery +/- radiation or chemotherapy
What is brachytherapy?
Radioactive isotopes applied directly = tumour receives highest dose and surrounding tissue is spared, largely replaced by radiosurgery
What are the different types of radiosurgery?
High energy photons produced by linear accelerators
The gamma knife
Charged particles (less common)
What is radiosurgery best for used for treating?
Highly focal malignant gliomas
When is surgery used to treat grade II astrocytomas?
To control seizures or treat herniations and CSF obstruction (cytoreduction may also be used)
What are poor prognostic indicators for grade II astrocytomas?
Age >45, low performance score, tumour >6cm or crossing midline, incomplete resection
What are the two kinds of malignant astrocytomas?
Anaplastic astrocytoma and glioblastoma multiforme
What are some features of anaplastic astrocytomas?
Can arise de novo
Median survival is 2 years
What are some features of glioblastoma multiforme?
Most common primary tumour
Median survival is <1 year
Spread via white matter tracking or CSF pathways
How are malignant astrocytomas treated?
Surgery = non-curative, cytoreduction to reduce mass effect, supramarginal resection if non-eloquent
Post operative radiotherapy = external beam radiation
What are some features of oligodendroglial tumours?
Account for 20% of glial tumours
Adults aged 25-45 with smaller peak age 6-12
Occur in frontal lobe and present with seizures
Where do oligodendroglial tumours infiltrate?
Subarachnoid space and leptomeninges
What is the appearance of oligodendroglial tumours?
Solid and grey/pink cut surface
What are collision tumours?
Oligodendroglial cells coexist with astrocytic cells
Originate from O2A cells
How are oligodendroglial tumours different from astrocytomas?
Show calcification, cysts and peritumoural haemorrhage
How are oligodendroglial tumours treated?
Surgery and chemotherapy
Median survival is 10 years
What chemotherapy agents are oligodendroglial tumours sensitive to?
Procarbazine, lomustine and vincristine
What cells do meningiomas arise from?
Arachnoid cap cells = represent 20% of intracranial neoplasms
What are some features of meningiomas?
Mostly asymptomatic
More common in men
Histologically benign and slow growing
What are the symptoms of meningiomas?
Headaches, cranial nerve neuropathies, regional anatomical disturbances
What is a meningioma en plaque?
Subgroup defined by presence of carpet or sheet like lesion that infiltrates the dura = remove all bone to prevent recurrence
What are the classifications of meningiomas?
Classic, angioblastic, atypical
Malignant = clear cell, chorioid, rhabdoid papillary, radiation induced
What does a CT of a meningioma show?
Homogenous, densely enhancing, oedema and hyperostosis
What does an MRI of a meningioma show?
Dural tail and patency of the dural sinuses
How are meningiomas treated?
Surgery and radiotherapy
5 year survival is 90%
What are some examples of nerve sheath tumours?
Schwannomas (neuromas), neurofibromas, malignant peripheral nerve sheath tumours
What are acoustic neuromas?
Vestibular schwannomas = associated with neurofibromatosis II
What are the symptoms of an acoustic neuroma?
Hearing loss, tinnitus and dysequilibrium
Hydrocephalus may occur
How are acoustic neuromas treated?
Radiation and surgery
25% managed with a hearing aid
50% managed surgically
How is the gamma knife used to treat acoustic neuromas?
Given to 25% of patients = usually if tumour <3cm, given in one sitting
What are the post-op complications of acoustic neuromas?
Facial nerve palsy, corneal reflex, nystagus and abnormal eye movements
What is the prevalence of germ cell tumours?
90% affect those <20
Peak incidence between age 10-12
More common in males
What are some features of germ cell tumours?
Iso/hyperdense on CT
Often mixed histology
May metastasise via CSF
What are the most common type of CNS germ cell tumour?
Germinomas = radiosensitive with 65-95% 5 year survival
What are the types of non-germinomatous germ cell tumours?
Teratoma, yolk sac tumour, chroriocarcinoma and embryonal carcinoma = less radiosensitive with 17-38% 5 year survival rate
What investigations should be done for any child with a midline brain tumour?
Perform AFP, beta HCG and LDH = if negative do biopsy
How do pituitary tumours present?
Bitemporal hemianopia and endocrine abnormality
How can acromegaly cause death?
Due to HOCM = need surgery and somatostatin analogues
How does panhypopituitarism present?
Pallor, yellow tinge and fine wrinkling of skin, absent axillary hair, puffy expressionless face
In what order are pituitary hormones disturbed in hypopituitarism?
GH - LH and FSH - TSH - ACTH - prolactin
