Neuro-oncology Flashcards
How do you investigate a patient with multiple intracranial lesions and a history of breast cancer?
The patient will need a full metastatic work up with CT chest abdomen and pelvis, tumour markers if indicated and an MRI brain with and without contrast to further delineate the lesion.
What is the differential diagnosis of multiple intracranial lesions?
Metastasis – lung, breast, melanoma and leukaemia; Abscess – bacterial, toxoplasmosis, Cryptococcus, aspergillus, herpes encephalitis; Glioma – Multicentric GBM, tuberous sclerosis – giant cell astrocytomas, multiple meningiomas, lymphoma, PNET and multiple neuromas (NF); Inflammatory – tuberculosis, granuloma, amyloidosis, sarcoidosis, vasculitis; Demyelination – MS; Radiation necrosis; Vascular – haemorrhages, venous infarct, strokes and moya moya disease.
What are the indications for biopsy?
If no primary disease can be found (10%), to rule out radiation necrosis if previously had brain radiation or unusual presentation where infection or malignancy cannot be differentiated.
What are the indications for surgery on an intracranial metastasis?
Primary disease is controlled, expected disease free survival, good prognosis, KPS >70, young age, fewer than 4 lesions and absence of leptomeningeal enhancement.
What factors favour surgery over radiotherapy?
Surgical accessibility, undiagnosed primary allows histological diagnosis, rapid deterioration due to mass effect, lesion causing hydrocephalus, rapid weaning of steroids, cystic lesions, lesions >3cm and radioresistant tumours.
Which metastases are radioresistant?
Thyroid, renal and melanoma.
What factors favour radiotherapy over surgery?
Avoids multiple craniotomies, lesions which are radiosensitive (small cell lung ca, germ cell tumours, multiple myelomas and leukaemia) and patients not fit enough for surgery.
Should WBRT follow resection of the metastasis?
Yes – it significantly improves the control of intracranial disease.
What is the prognosis of multiple brain metastases?
8 weeks with steroids, 6 months with WBRT and 14 months with surgery and WBRT. Patients with more than 4 metastases are not treated surgically.
What is the differential diagnosis of leptomeningeal enhancement?
Neurogenic – high or low ICP; Inflammatory – sarcoid; Infection – meningitis including TB meningitis, fungal infection or granulomatous cell infiltration; Vascular – ischaemia, venous thrombosis, SAH, Trauma; Malignancy – local tumour infiltration, primary meningeal glioma, PNET, Primary meningeal melanoma and rhadomyosarcoma of the meninges.
What is the most common cause of meningeal carcinomatosis?
5% of all patients with cancer get meningeal carcinomatosis – mainly breast, lung, head and neck cancers, melanoma and gastric malignancies.
How would you investigate a patient with meningeal carcinomatosis?
CSF cytology, cranial and spine MRI, CT CAP for primary and meningeal biopsy from a region of meninges that enhances on the MRI if CSF cytology is non-diagnostic.
What is the diagnostic yield of an LP in meningeal carcinomatosis?
40-50% - but improves to 90% on the third LP if >10ml of CSF is taken every time.
What is the mechanism of invasion with meningeal carcinomatosis?
Haematogenous spread via dural arterial circulation and also in the spine retrograde venous circulation from Batson’s venous plexus and perneural lymphatic spread. These malignant cells then enter the CSF and are seeded throughout the meninges.
Which areas are mostly affected by meningeal carcinomatosis?
Basal cisterns, posterior fossa and cauda equina.
What are the classical features of meningeal carcinomatosis?
Enhancement and enlargement of the cranial nerves, superficial linear dural enhancement, irregular tentorial or ependymal enhancement, cisternal / sulcal obliteration, communicating hydrocephalus, multiple superficial brain nodules, spinal cord enlargement and asymmetry of the root with clumping of the cauda equina.
What are the treatment options for meningeal carcinomatosis?
Analgesia, focal radiotherapy, seizure management and treatment of hydrocephalus.
What are the pros and cons of Ommaya reservoir placement?
Pros - CSF sampling or drug administration is easier, better drug distribution in the cranial CSF spaces, reduces neurotoxicity a drug doses are less, avoids complications of LPs and ensures drug administration in to the CSF. Cons – Infection risk, seizures – if drug extravasates into brain, small ventricles are technically challenging and catheter obstruction.
What is the treatment of meningeal carcinomatosis?
Palliative radiotherapy may provide symptom relief. Chemotherapy is given intrathecally (methotrexate).
What is the prognosis of meningeal carcinomatosis?
Palliative with survival around 2 months, although those with lymphoma / leukaemia have a better prognosis with some remaining in remission for years.
What are the MRI findings with primary CNS lymphoma?
Multiple enhancing lesions that are dispersed throughout the brain with some abutting the ventricular system.
What the differential diagnosis of a periventricular enhancing lesion?
Primary CNS lymphoma, ependymoma, metastases, multifocal GBM, toxoplasmosis, brain abscess, MS and vasculopathy.
How would you investigate a patient with ?primary CNS lymphoma?
Metastatic work up with CT-CAP, blood tumour markers, HIV and CSF sampling.
Should steroids be given if the patient is suspected of having lymphoma?
No as this will make the biopsy less successful as the lesion vanishes.
How is primary CNS lymphoma treated?
High dose methotrexate systemic and intrathecal. Radiotherapy to the neuroaxis is only given if the patient is
What is the role of surgery in Primary CNS Lymphoma?
Diagnostic for biopsy only.
What is the prognosis of primary CNS lymphoma?
Without any treatment
What is the differential diagnosis of a single posterior fossa mass in a young patient?
Medulloblastoma, Haemangioblastoma, pilocystic astrocytoma, ependymoma and metastasis. Less likely causes are tuberculoma, cavernous haemangioma, abscess, glioma, lymphoma, dermoid and haemorrhage.
What are the locations of medulloblastomas?
In children they tend to be midline whilst in adults they are more laterally placed.
How would you manage a patient with tumour of the vermis obstructing the 4th ventricle?
Initial management would be treatment of the hydrocephalus as a result of the 4th ventricular obstruction. Steroids will reduce local mass effect. Then a metastatic work up is needed with MRI+/- contast of the brain and spine (for drop mets). Definitive surgical treatment is needed.
What is the approach to a vermian / 4th ventricular lesion?
Concorde position with midline incision and posterior fossa craniectomy. A frazier burr hole may be places (6cm above and 3 cm lateral to the inion).
What is the treatment of medulloblastoma?
Resection followed by radiotherapy to the whole neuroaxis even when no residual or other lesion is seen on imaging.
What is the treatment of a haemangioblastoma/cavernoma/ pilocystic astrocytoma?
Full surgical resection is curative and adjuvant radiotherapy is debated.
What is the management of a tuberculoma?
Full surgical resection is not required with a tuberculoma but the patient needs prolonged treatment with anti-tubercular medications.
What are the differences between medulloblastomas in childhood and adults?
Peak incidence in children is 3-5 years, midline location and show contrast enhancement as they are mostly solid with well defined margins. In adults they occur between 20-40 years, laterally placed and enhance less with contrast due to the cystic and necrotic nature. The margins are usually poorly defined.
Which familial conditions are associated with medulloblastomas?
Gorlin syndrome, rubinstein-taybi syndrome, ataxia telangiectasia, turcot’s syndrome, Li-fraumeni syndrome, Neurofibromatosis and tuberous sclerosis.
What is the prognosis of a medulloblastoma?
Larger tumours with invasion of the brainstem and dissemination mean complete resection is unlikely and is associated with a poorer outcome. Children have better outcomes as the lesions are less invasive. 5 year disease free survival can be up to 80%. Undifferentiated histological subtypes have a better prognosis than the differentiated subtype.
What is the differential diagnosis of a young patient with an enhancing hyperostotic lesion of the skull base?
Fibrous dysplasia, Ossifying fibroma, primary bone tumour, bone metastasis, lymphoma, paget’s disease, osteomyelitis or meningioma.
In a patient with fibrous dyplasia what pre-op investigations are needed?
Fine cut CT of the skull base, ophthalmology assessement, angiography for ?embolisation and lab studies for Ca and ALP (Paget’s).
What are the indications for surgery in fibrous dysplasia?
Cosmetic deformity, compromise of vision / ocular mobility, intractable headaches, rapid or aggressive growth.
What is the pathology of fibrous dysplasia?
This is not a true neoplasia but is a result of the arrest of the bone maturation in the woven lamellar stage. Growth usually slows after puberty.
What are the surgical goals in fibrous dysplasia?
Decompression of vital structures. Due to its polyostotic structure and poor demarcation complete resection may not be possible and carries the risk of future growth. Patients should also be on a bisphosphonate or calcitonin in non-operative cases.
Should radiotherapy be given to fibrous dysplasic bone?
No evidence for its use and could result in malignant transformation.
What is McCune-Albright syndrome?
Characterised by fibrous dysplasia, precocious puberty with endocrinopathies and cafe au lait spots.
What the classification of intra-orbital tumours?
Excluding primary ocular tumours the intraorbital tumours are classified based on where they arise from: Intraconal lesion are within the muscle cone and result in visual loss and mobility restriction (diplopia), Extraconal lesion are outside the muscle cone and cause proptosis / orbital displacement as well as visual loss and impaired mobility and Intracanalicular are within the optic canal and cause loss of vision with optic disc swelling and loss of vision but rarely proptosis.
What is the annulus of Zinn?
The aperture formed by the cone of muscles.
Which structures are within the annulus of Zinn?
Optic nerve, ophthalmic artery, orbital branch of the meningeal artery, sympathetics from the ICA, superior and inferior divisions of the oculomotor nerve, the nasociliary nerve and the abducent nerve.
What is the differential diagnosis of an extra-axial intra-conal lesion that does not affect the globe?
Hemangioma, optic sheath meningioma, neurofibroma, melanoma, lymphoma, vascular, endocrine, infectious or inflammatory disease.
What is the initially management of a patient with an intraorbital tumour?
Urgent ophthalmology assessment, CT and MRI and metastatic work up with CT-CAP. Present the options of resection or conservative management.
What is the prognosis following intra-orbital haemangioma resection?
Complete resection is curative.
What are the risk factors for intra-cerebral abscess formation that can be sought from the history?
Weight loss, night sweats, IV drug use, cardiac or pulmonary abnormalities, HIV, recent chemotherapy, lymphoma etc
What is the differential diagnosis of multiple intracerebral ring enhancing lesions?
Multiple bacterial abscesses, neurocystercosis, toxoplasmosis, tuberculomas, metastasis or multifocal GBM.
What are the initial investigations for a patient with multiple intracranial ring enhancing lesions?
Markers of infection (FBC / CRP / ESR etc), Immune status (HIV / HepB / HepC), CT-CAP, blood cultures, Anti-toxoplasma titres, western blot to detect taenial solium antigens, ECG and abdominal USS.
How can an abscess be differentiated from a tumour on MRI?
Diffusion weighted imaging where abscesses show restricted diffusion and GBMs or cystic mets do not.
What are the histological stages of cerebral abscess formation?
1- Early cerebritis (14 days) with central necrosis, thin wall with collagen capsule and CT shows a thin enhancing wall. Note the capsule wall is thinner along the ventricles so is prone to rupture into the ventricles.
What are the main sources of bacterial abscesses?
Haematogenous (25%) with the most common organism being strep viridians, then from the middle ear or paranasal sinuses with strep milleri and then third route is trauma or post-surgical with staphylococcus aureus or epidermidis.
What is the treatment of intracerebral abscesses?
Antibiotics based on cultures so a brain biopsy may be needed or surgical resection of a lesion if there is significant mass effect. Steroids for symptom relief.
A patient with speech difficulty, shoulder weakness and tongue wasting has lesion in which location?
Jugular foramen (CN 9 / 10 / 11). The tongue wasting shows CN12 involvement which would then suggest extracranial disease (Collet-Sicard).
What is the most common cause of a tumour at the jugular foramen?
Glomus jugulare (paraganglioma). The differential diagnosis also includes schwannoma, meningioma, chordoma, endolymphatic sac tumour, temporal bone carcinoma and metastases.
How would you investigate a patient with a jugular foramen tumour?
CT-CAP and CT-angiogram / formal DSA, serum and urine catecholamines and urine VMAs.
Which other tumours are associated with glomus tumours?
Glomus tumours are neuroendocrine tumours and patients should be investigated for a concurrent phaeochromocytoma.
Why are serum catecholamines sent in the investigation of phaeochromocytoma?
The conversion of NAdr to Adr requires phenylethanolamine-N-methyl transferase (PNMT) in the medulla. A high level of Adr therefore signifies a phaeochromocytoma whereas high NAdr can be produced by chemically active glomus tumours.
How should hypertensive crisis in a patient with a phaeochromocytoma be managed?
With both alpha (phenoxybenzamine) and beta (propanolol) blockade. Alpha blockade must be given first to prevent worsening of the hypertension.
What is the most common vessel to supply a glomus tumour?
The ascending pharyngeal artery. Other feeders include the occipital and maxillary arteries from the ECA as well as the vertebrobasilar system.
What are the treatment options for glomus tumours?
Surgery / radiosurgery / radiotherapy.
What are the outcomes following radiotherapy for a glomus tumour?
94% 20 year survival and 75% 20 year disease free survival.
What is the aim of radiosurgery for glomus tumours?
Tumour control with a 2.1% recurrence rate and no mortality. The tumour gets smaller in only 1/3 of cases.
What are the outcomes following surgery for glomus tumours?
1% mortality, 3% recurrence and 90% gross resection.
What pre-operative steps should be taken prior to operating on a glomus jugulare tumour?
Angiogram + embolisation, alpha and betablocker therapy to control BP if the tumour is hormonally active, intraoperative cranial nerve monitoring along with brainstem auditory evoked responses and SSEPs.
Which nerves are most at risk during surgery on a glomus tumour?
The lower cranial nerves (10/11) are usually pushed medially by the tumour so are at less risk than the 7 and 9.
What is the management of patients with bilateral glomus tumours?
Resect one at a time and only resect the second tumour if there was no cranial nerve deficit from the first resection. Alternatives include radiosurgery.
What are the key features in the pathology staining for a glomus tumour?
Sustentacular cell density and staining of the sustentacular cells with S100 is inversely proportional to the aggressiveness of the tumour. Low staining means very aggressive therefore.
What is the embryological origin of a glomus tumour?
They are of neuroectodermal origin.
Where are the genes for glomus tumour development found?
On chromosome 11 resulting in a germline mutation in succinate dehydrogenase subunits (mitochondrial enzyme) in an autosomal dominant fashion with variable penetrance from the father.
What is the classification system for jugular foramen syndromes?
Vernet = 9/10/11 due to an intracranial lesion at the jugular foramen, Collet sicard = 9/10/11/12 due to an extracranial skull base lesion, Schmit 10/11, Jackson = 10/11/12 vascular infarction of the medullary tegmentus , Tapia 10 to larynx only/ 11/12/sympathetic and Villaret 9/10/12 and sympathetic due to a high cervical lesion
How are glomus tumours classified?
Fisch classification: A – limited to the middle ear cleft; B – limited to the tympanomastoid; C – involvement of the infralabyrinthine segment and along the carotid canal to the petrous apex; D – Intracranial extension. Glassock-Jackson classification: A – small involving jugular bulb, middle ear and mastoid; B – extends into the IAC; C – extends to the petrous apex +/- intracranial extension; D – Beyond the petrous apex to the clivus or infratemporal fossa +/- intracranial extension.
What are the jugular foramen syndromes?
Vernet – CN9, 10 & 11 – intracranial lesion; Collet-sicard - CN9, 10, 11 & 12 – skull base lesion; Schmidt – CN10 & 11 ; Jackson – CN 10, 11 & 12 – vascular infarction of the medullary tegmentum; Tapia – CN Laryngeal 10, 11, 12 & sympathetics – high cervical lesion; Villaret – CN 9, 10, 11, 12 & sympathetic.
What are the features of a colloid cyst on MRI?
Circular homogenous lesion with thin rim enhancement that is hypointense on T1 and T2 sequences.
What is the differential diagnosis of a 3rd ventricular lesion?
Most likely is a colloid cyst; Differential diagnosis is MATCH-O-GRAM: Meningioma, AVM, Aneurysm, Teratoma, Colloid cyst, Craniopharyngioma, Choroid plexus papilloma, Hypothalamic hamartoma, histiocytosis, Optic glioma, Germinoma, Rathke’s cyst, Abscess and metastasis.
What are the treatment options for a colloid cyst?
Image guided resection, stereotactic aspiration or CSF diversion procedure (VP shunt)
What are the approaches to the 3rd ventricle?
Interhemispheric transcallosal – good if the ventricles are enlarged due to short trajectory, no cortical transgression and visibility of both foramen of Monroe. Complications include weakness, akinectic mutism and memory deficits. Endoscopic approach – less invasive, direct visualization, reduced hospital stay, shorted op, less retraction on the fornix. Difficult if ventricles are small and poor control of bleeding. Transcortical transventricular approach – good for approaching the anterior 3rd ventricle and anterior horn, trajectory through the middle frontal gyrus (F2). Complication of higher seizure risk. Subfrontal approach – best for anterior inferior 3rd ventricular lesions e.g. craniopharyngiomas. 4 surgical corridors – subchiasmal, opticocarotid, lamina terminalis (if pre-fixed chiasm) and transfrontal trans-sphenoidal (if pre-fixed chiasm). Note stereotactic aspiration can be performed if the patient is not a candidate for craniotomy.
What is the technique for aN intrahemispheric transcallosal approach to the 3rd ventricle?
MRI Stealth, ¾ suttar bicoronal incision (more on the right than the left with lateral exposure to the temporalis fascia), 2 burr holes 3 cm anterior and 3cm posterior to the coronal suture either side of the SSS, open dura in a C-shape fashion flapped over the SSS, placement of retractors on the right side of the falx and dissect down the interhemispheric fissure identifying the cingulate gyrus, callosomarginal and pericallosal arteries and then the corpus callosum. Incise through the CC within 2 cm of the genu to enter the lateral ventricle. Then the interforniceal approach or the transforamen of Monroe approach or the transchoroidal approach to the 3rd ventricle.
Which veins are visible in the lateral ventricle?
The thalamostriate veins approaches from posterior with the choroid plexus medial to it and the septal and caudate veins approach from anterior.
Which vein has to be sacrificed for the lateral ventricular trans foramen of Monroe approach?
The thalamostriate vein (well tolerated).
What is the complication of bilateral forniceal injury?
Short-term memory deficit and inability to learn new things.
What are the complications of an interhemispheric approach?
Hemiparesis, forniceal injury, seizures, stroke in the region of the ACA (pericallosal or callosomarginal, superior sagittal sinus thrombosis, internal cerebral vein injury and IVH
When is the transchoroidal approach used?
When the foramen of Monroe is too small to enter the 3rd ventricle and an incision is made medial to the choroid plexus along the tenia fornicis through the tela choroidae.
What is the potential complication of bilateral cingulate gyrus retraction or thalamic injury?
Transient mutism
What is the possible complication of a wide opening of the corpus callosum?
Disconnection syndrome
What are the indications for operating on a meningioma?
Uncertain diagnosis, increase in size or change in radiological features e.g. oedema, to prevent neurovascular compromise and location of the tumour
What are the implications of a venous sinus injury?
Haemorrhage, Air embolism and Venous infarction
How can one monitor for an air embolism?
Precordial or oesophageal doppler and monitor PCO2
What are the options for management of residual meningioma post-op?
Serial MRI, radiotherapy or SRS depending on size of residual
What is the tumour control rate with radiotherapy to residual meningioma?
84-100%
What are the complications of SRS?
Oedema, seizure, cranial nerve deficit, hemiparesis, headache, mental status change and imbalance.
What are the neurosurgical causes of a patient with bilateral visual deterioration?
Skull base meningioma, pituitary adenoma and craniopharyngioma
What are the features of foster-kennedy syndrome?
Unilateral anosmia, ipsilateral optic atrophy, contralateral papilloedema - seen with olfactory groove meningiomas
How would you investigate an olfactory groove meningioma?
MRI / MRA and MRV or CTV if concerns re sinus patency
How can an olfactory groove and a tuberculum sella meningoma be differeniated?
The location of the chiasm is located inferolaterally with an olfactory groove meningioma and superiolateral to the tumour with a tuberculum sella meningioma
What are the operative approaches to an olfactory groove meningoma?
1) Subfrontal +/- orbital osteotomies or 2) Pterional; 3 Interhemispheric
What are the advantages of a bicoronal subfrontal approach to an olfactory groove meningoma?
Allows early devascularisation; potential access to the orbits to coagulate the ethmoidal arteries; orbital osteotomies reduce frontal lobe retraction; pericranium allows for skull base reconstruction;
What are the disadvantages of a bicoronal subfrontal approach to an olfactory groove meningoma?
Sacrifice / damage to the superior sagittal sinus, entry into the frontal air sinus results in increased risk of post-op CSF leak and infection, late visualisation of the ACAs and optic nerve
What are the advantages of a pterional approach to an olfactory groove meningoma?
Early exposure of the optic apparatus and ACAs before manipulation of the tumour, shorter distance to the tumour, does not require entry into the frontal air sinus (reduced risk of csf leak and infection), does not require SSS sacrifice and less frontal lobe retraction
What are the disadvantages of a pterional approach to an olfactory groove meningoma?
Narrow working angle, difficult to reach upper portion of the tumour, cannot access ethmoidal arteries until late and difficult to repair any skull base defect
What are the advantages of an interhemispheric approach to an olfactory groove meningioma?
Preserves the SSS and does not require opening of the frontal air sinus
What are the disadvantages of an interhemispheric approach to an olfactory groove meningioma?
Higher risk of contusions to the frontal lobes, long and narrow operative route, risk of damage to bridging veins and late access to blood supply
Describe the steps in resection of an olfactory groove meningioma using the subfrontal approach?
Cauterization of the ethmoidal arteries in the orbit is optional and reduces intraoperative haemorrhage; Bicoronal flap; Craniotomy and control of the SSS anteriorly; Subfrontal retraction of the frontal lobes to reveal the tumour; Cauterization of the base and devascularization; Arachnoid plane dissection; Debulk of the tumour using CUSA; Separation of the tumour from the ACAs and optic nerve / chiasm; Repair of the fossa floor / air sinus
What is the recurrence rate of olfactory groove meningiomas?
Higher recurrence rate than convexity meningiomas. Roughly 30% at 5 years so aggressive resection, resection of the SSS and drilling of hyperostotic bone should be performed.
What is the differential diagnosis of a lesion of the sphenoid wing?
Meningioma, haemangiopericytoma, primary bone lesion, dural metastasis, AVM, infective collection or inflammatory lesion such as sarcoid
How are sphenoid wing meningiomas classified?
Medial, intermediate and lateral
How would you position a patient for resection of a sphenoid wing meningioma/
Supine with shoulder roll and head turn 30 deg;
What approach would you use to resect a sphenoid wing meningioma?
Right pterional or cranial orbitozygomatic approach; exposure of the lateral sphenoid wing is performed extradurally via drilling down the sphenoid bone; Meningioma should be internally debulked capsule collapsed down and dissected from normal brain; En passage vessles in the sylvian fissure should be spared. Hyperostotic bone should be drilled down.
How do you repair a large dural defect following the resection of a sphenoid wing meningioma via pterional approach?
Fascia, pericranium or dural substitute followed by fibrin glue e.g. tisseal
What is the Simpson grading of meningioma resection?
1 - full resection and removal of all dura 2 - full resection and bipolar of dural origin 3 - full resection and no bipolar of dural origin 4 - Residual meningioma left 5 - Decompression / biopsy
What is the recurrence rate of a simpson grade 2 resection at 5 years?
20%
Young patient with a rapidly growing dural mass with significant surrounding oedema?
Haemangiopericytoma less likely aggressive meningioma, metastasis, lymphoma or abscess
What is the standard management of symptomatic meningomas?
Operative work up, steroids, seizure prophylaxis and MRI+C, MRA +- MRV; Think about perioperative embolisation
How is haemangiopericytoma classified in the 2007 WHO classification?
Tumour of the meninges - haemangiopericytoma is subclassified as a mesenchymal tumour i.e. non-meningothelial along with tumours such as solitary fibrous tumour, malignant fibrous histiocytoma and chondrosarcoma (note: meningiomas are classified as meningothelial tumours)
What is the role of chemotherapy and radiotherapy for haemangiopericytoma?
Controversial - however radiotherapy or SRS is used both for primary and recurrence.
When is chemotherapy used for haemangiopericytoma?
Usually as salvage treatment. Most commonly used agents include Doxorubicin, ifosfamide, etoposide, methotraxate, cyclophosphamide, cisplatin, mitomycin and vincristine are used.
What is the prognosis of haemangiopericytoma?
5 year 90% survival
What percentage of patients with haemangiopericytoma have recurrence and metastases?
80% have recurrence following resection and 30% have metastases
Where do haemangiopericytomas metastasize to?
Spine, long bones, liver, lung and abdominal organs
Where could a meningioma in the parasellar be arising from?
The medial sphenoid wing, anterior clinoid process or the cavernous sinus
Where is the optic nerve compressed with the patient has an inferior arcuate visual field defect?
Superiorly - as these fibres supply the superior retina which recognises light which comes inferiorly
How would you approach a clinoid meningioma?
Fronotemporal craniotomy (frontally biased pterional craniotomy) to allow early decompression of the optic nerve and enhanced exposure for resection
What is the classification of clinoidal meningiomas?
Type 1 have attachment to the anterior clinoid process inferiorly and encase the carotid artery. They adhere to the adventitia due to the lack of an arachnoid membrane; Type 2 originate from the lateral part of the anterior clinoid have an arachnoid plane between it and the carotid artery; Type 3 originate from the optic foramen and may encase the carotid artery.
What are the main goals of surgery for clinoidal meningiomas?
Decompress the optic nerve and achieve as maximal resection as possible.
What are the options for a residual meningioma that is too big for SRS?
Fractionate radiotherapy
What are the critical structures in the vicinity of clinoidal meningiomas?
CN2, CN3, ICA, MCA, ACA, pituitary stalk and contents of the cavernous sinus
Where are velum interpositum meningiomas on MRI?
Velum interpositum meningiomas appear within the posterior part of the 3rd ventricle underneath the splenium of the corpus callosum
What is the relationship of the internal cerebral veins to a velum interpositum meningioma?
The veins are beneath the meningioma
What is the differential diagnosis of a posterior 3rd ventricle lesion?
Pineoblastoma / Pineocytoma Germ cell tumours Tectal / thalamic glioma Astrocytoma Ependymoma Meningioma Metastasis
What are the approaches to the posterior 3rd ventricle?
Infratentorial supracerebellar approach - if the veins are above the lesion Occipital transtentorial - if the veins are below the lesion Posterior transcallosal - if th veins are below the lesion
What structures form the roof of the third ventricle?
Dorsal and ventral layers of the tela choroida Body and crus of the fornix
What is the velum interpositum?
The space between the dorsal and ventral tela choroida
What structures lie within the velum interpositum?
Internal cerebral vein Medial posterior choroidal artery
What structures surround the pineal region?
Anterior: 3rd ventricle Posterior: Quadrigeminal cistern Lateral: Thalamus Superior: Splenium of the corpus callosum Inferior: Tectum
What are the complications associated with surgery of the posterior 3rd ventricle?
CN3 palsies Parinaud syndrome Deep venous system injury / infarction Air embolism Visual deficit
Where do velum interpositum meningiomas arise from?
Arachnoid cap cells within the choroid plexus
What is the diagnosis in a patient with sudden onset severe headache with temporary visual loss?
Pituitary apoplexy
How would you investigate a patient with pituitary apoplexy?
Pituitary profile CT Dark on T2 MRI Opthalmology assessment
What is a dangerous complication of pituitary apoplexy?
Addison’s syndrome
What is the difference between Addison’s disease and syndrome?
Addison’s disease is hypocortisolism due to adrenal gland dysfunction. Addison’s syndrome is any other cause.
Continue Ch11
middle part
What features of a bone lesion suggest malignancy?
Irregular margins, no sclerosis and multiple lesions
What is the most common primary bone tumour of the skull?
Osteoma - round sclerotic tumours arising from the outer table of the skull. Hot on bone scans.
What is Gardner’s syndrome?
Multiple osteomas, colon polyps and soft tissue tumours
What are the two types of haemangioma?
Cavernous and capillary (very rare). Treat with excision or cement vertebroplasty if in the spine.
What are the x-ray / CT appearance of a haemangioma?
Trabecular pattern. If radial then has a sunburst appearance. Sclerotic margins in 1/3,
What are dermoid / epidermoid cysts?
Benign ectodermal inclusion cysts
What is the difference between a teratoma and a dermoid?
Teratomas contain 2 or more germ cell layer tissue derivatives e.g. teeth, dermoids only contain ectoderm. Whilst Epidermiods contain squamous epithelium and keratin only.
What is this midline lesion?
Skull dermoids
What is this lesion?
Langerhans cell histiocytosis
Appears as a punched out lytic lesion skull xray
Where do chodomas arise?
Clivus and sacrum
What cells are characteristic of a chordoma?
Physaliphorous cells (contain intracellular mucin)
What are the MRI features of a chordoma?
Bright on T2, dark on T1 and no enhancement.
What are chordomas remnants of?
Notochord (which normally forms the intervertebral discs)
What is the recurrence rate of chordomas?
85% so aggressive radiotherapy or proton beam therapy is employed.
10% metastasise (lung, liver and bone)
What % of primary bone tumours are chordomas?
50%
M>F
Usually sacrococcygeal but can be in C2.
Limited by presacral fascia so do not normally invade the rectum.
Diagnosis?
Hyperostosis frontalis interna
What is the treatment for sacrococcygeal chordoma?
En-bloc excision (Sacrectomy)
High dose radiotherapy / proton beam more effective
Diagnosis?
Paget’s disease
Diagnosis?
Osteopetrosis
What chemotherapy is used for chordomas?
Imatinib aka Glivex (tyrosine kinase inhibitor of the mTOR pathway). Stabilises the disease in 70% Ref: Hindi et al 2015
What is the classical feature of hyperostosis frontalis interna?
The midline bone at the insertion of the falx is spared.
More common in Females (9:1)
Associated with acromegaly, hyperprolactinaemia, hyperphosphataemia and DISH.
What conditions cause diffuse thickening of the skull?
Hyperostosis frontalis interna
Fibrous dysplasia
Osteopetrosis
Paget’s disease
Diagnosis?
Fibrous dysplasia
What is this X-ray finding?
Shepherd’s crook deformity, associated with fibrous dysplasia of the prox femur
What is the median survival of a chordoma?
6.3 years
How do you investigate someone with suspected hyperostosis frontalis interna?
GH / Prolactin / ALP / Ca / Parathyroid levels
Skull Xray or CT
How is hyperostosis frontalis interna treated?
If needs treating, then excision and cranioplasty
What is fibrous dysplasia?
A non-neoplastic condition where bone is replaced with expansile fibrous connective tissue. Risk of malignant transformation <1%.
What sites are commonly affected by fibrous dysplasia?
Skull, face, proximal femur and ribs
What is McCune-Albright syndrome?
Polyostosic fibrous dysplasia, precocious puberty and cafe au lait spots
What are the 3 patterns of involvement of fibrous dysplasia?
- Mono-ostotic
- Poly-ostotic
- Part of McCune Albright syndrome (polyostotic fibrous dysplasia, precious puberty and cafe au lait spots)
What are the 3 forms of fibrous dsyplasia?
Cystic, Sclerotic and mixed
What are the reasons to treat fibrous dysplasia?
Cranial nerve-related compression (visual loss, diplopia, hearing loss, trigeminal neuralgia and facial weakness)
Cosmesis
Pathological fractures (long bones / maxilla etc)
What imaging studies do you request for fibrous dysplasia?
Skeletal survey, CT head and dental films (OPG)
What is the natural history of fibrous dysplasia?
Slow growth which does not usually progress after skeletal maturity is reached so if possible wait until age 10 /12 years before treatment.
Rapid growth can occur with GH excess and this should be managed aggressively.
What are the medical treatment options for fibrous dysplasia?
Calcitonin
Bisphosphonates
Treat GH excess
What structures pass through the SOF?
Lateral (extraconal) - Lacrimal (V1), Frontal (V1), Trochlear (CN4)
Medial (intraconal) - Superior CN3 div, Nasocillary, Inferior CN3 div and Abducens (CN6)
**Mnemonic = Lucious French Tarts Sit Naked In Anticipation**
What is Meckel’s cave?
A CSF filled cavity containing the trigeminal ganglion that lies between the periosteal and meningeal layers of dura that sits posterio-lateral to the cavernous sinus with the cavernous carotid medial and petrous carotid inferior.
What passes through F. ovale? (mnemonic = OVALE)
Otic ganglion
V3
Accessory meningeal
Lesser petrosal nerve
Emissary vein
What is Bill’s bar?
Vertical crest separating the Facial nerve anteriorly from the superior vestibular nerve posteriorly.
(7up, Coke down)
What is central pyrexia?
A persistent feve >38 degrees that is not due to other causes such as sepsis in the context of brain insult. Mechanism is unknow but thought to be due to hypothalamic dysfunction. It is seen with haemorrhage in the lateral ventricles.
What is gamma knife?
Stereotactic radiosurgery from 201 Cobolt-60 sources arranged in a spherical array. The lesion is placed in the centre such that radiation beams converge on the lesion. Multileaf collimaters allow the beam to be tightly conformed to the lesion. This allows a high dose to be given to the lesion and spare the surrounding brain.
What is the action of Erlobtinib / Debrafnib etc?
Tyrosine kinase pathway inhibitors affecting the BRAF pathway (RAS>RAF>MEK>ERK)
How does cisplatin work?
Platinum Alkylating agent
How do everolimus / serolimus / rapamycin etc work?
mTOR inhibitors
What is the mTOR pathway?
Tyrosine kinase R > PIP2 conversion to PIP3 by PI3K > Akt > TSC-1 and 2 > mTOR > transcription factors for cell replication
How does vincristine work?
Microtubule inhibitor
Which chemotherapy agents are alkylating agents?
Carmustine
Cisplatin
Lomustine
Procarbazine
Temozolamide
What are the features on this histological slide?
The ovoid cells with a prominent nucleolus = neurons.
The arrow head is pointing at a mitotic figure.
The remaining cells are astrocytes on the background of the normal neuropil.
The presence of diffusely infiltrating astrocytes that are pleomorphic, as well as the mitotic figure, suggests a diffuse astrocytoma.
What are the features on this histological slide?
There is evidence of pseudopalisading surrounding central necrosis suggesting IDH-WT. There is a marked increase in cell density. There is vascular proliferation and the bottom arrow represents a thrombus within the vessel. This is in keeping with a high-grade astrocytoma (GBM).
What are the features on this histological slide?
There are regions of microvascular proliferation (mitotic figures within the endothelial cells) with endothelial hyperplasia resembling glomeruloid tufts. This is in keeping with a GBM.
What are the features on this histological slide?
There is evidence of pseudopalisading necrosis with regions of microvascular proliferation with endothelial hyperplasia and regions of haemorrhage. There is also thrombus within the vessels. This is in keeping with IDH-WT GBM.
What are the features on this histological slide?
There are Rosenthal fibres (eosinophilic intracystoplasmic inclusion) with bipolar astrocytes that have hair-like projections. There are no mitotic fibres visible. This is in keeping with a WHO grade 1 pilocytic astrocytoma. I would stain for mucin to differentiate between a pilomyxoid tumour.
