Tumours Flashcards
1.Which of the following features favour Rathke’s cleft cyst rather than craniopharyngioma?
A. Cystic element on MR
B. Involvement of suprasellar and sellar regions
C. Enhancement of the wall
D. Absence of calcification
E. High signal intensity on T1
D. Absence of calcification
Rathkes cleft cysts do not calcify. They affect women to men in a 2:1 ratio and adults from 40-60 years of age. They cause variable MR appearances depending on protein content of cyst. They can rarely show enhancement.
@# 9. Which brain tumour has the greatest incidence across all age groups?
A. Meningioma
B. Metastases
C. Pituitary adenoma
D. Haemangioblastoma
E. Glioma
E. Glioma
Gliomas consist of astrocytomas, oligodendrogliomas, paragangliomas, ganglogliomas and medulloblastomas
- Which of the following is an extra-axial posterior fossa tumour in adults?
A. Metastasis
B. Haemangioblastoma
C. Choroid plexus papilloma
D. Lymphoma
E. Glioma
C. Choroid plexus papilloma
Other extra-axial posterior fossa masses include acoustic neuroma, meningioma, chordoma and epidermoid.
(Ped) 13. Which is the most common site of metastatic spread in medulloblastoma?
A. Axial skeleton
B. Lymph nodes
C. Lung
D. Subarachnoid space
E. Liver
D. Subarachnoid space
Subarachnoid space is the most common, with drop metastases occurring in 40%.
- Which of the following features describes an intra-axial mass?
A. Cortex displaced towards bone
B. Mass contiguous with dura
C. Buckling of grey and white matter
D. Widened subarachnoid cistern
E. Dural feeding arteries
A. Cortex displaced towards bone
B-E are extra-axial features.
- Which of the following favours an arachnoid rather than an epidermoid cyst?
A. Hyperdense to CSF on CT
B. Encased vessels
C. Deviates from CSF on proton density
D. Restricted diffusion
E. Smooth margin
E. Smooth margin
A and C-E are features of epidermoid cyst. A and C demonstrate CSF-like density and have smooth margins.
- Which of the following best describes imaging changes in a colloid cyst?
A. Typically hypodense on non-contrast CT
B. Appears high SI on T1
C. Appears low SI on T2
D. Commonly widens septum pellucidi
E. Most commonly causes symmetrical enlargement of lateral ventricles
B. Appears high SI on T1
Protein content/paramagnetic effect of magnesium Mg2+/ calcium Ca2+/, Iron Fe, in a cyst cause increased T1 and T2 SI.
Colloid cysts appear iso/hyperdense on NCCT.
They can occasionally widen septum pellucidum and cause asymmetrical enlargement of the lateral ventricles.
- Which is the most common location for epidermoid in the Central Nervous System (CNS)?
A. Cerebellar pontine angle (CPA)
B. Suprasellar region
C. Perimesencephalic cisterns
D. Ventricles
E. Skull vault
A. Cerebellar pontine angle (CPA)
Located in CPA in 40%, accounting for 5% of CPA tumours.
- Which of the following favours dural meningeal carcinomatosis rather than leptomeningeal cacinomatosis?
A. Positive cytology
B. Short discontinuous thin sections of enhancement
C. Thin area of subarachnoid enhancement following convulsions of gyri
D. Discrete leptomeningeal nodules
E. Invasion of underlying brain with mass effect and oedema
B. Short discontinuous thin sections of enhancement
Dural meningeal carcinomatosis is rarely associated with positive cytology and involves localised or diffuse curvilinear enhancement underneath inner table in expected position ofdura.
- Which is the cause of a cystic rather than a haemorrhagic cause of brain metastases?
A. Malignant melanoma
B. Choriocarcinoma
C. Renal cell carcinoma
D. Thyroid carcinoma
E. Adenocarcinoma of the lung
E. Adenocarcinoma of the lung
Squamous cell lung cancer and adenocarcinoma of the lung cause cystic metastasis to the brain. Answers B-E are causes of haemorrhagic metastases
@# 23. Which is the most common location of oligodendroglioma?
A. Temporal lobe
B. Parietal lobe
C. Occipital lobe
D. Frontal lobe
E. Cerebellum
D. Frontal lobe
Most commonly involve cortical & subcortical white matter, occasionally through CC as butterfly glioma.
- A 2cm mass is seen on MR at the left CPA with uniform enhancement and high SI on T2 and dural tail. What is thediagnosis?
A. Vestibular schwannoma
B. Epidermoid
C. Metastatic deposit
D. Meningioma
E. Glomus tumour
D. Meningioma
Broad based attachment to petrous bone. More homogenousSI and less bright T2. Uniform enhancement distinguishesfrom vestibular schwannoma.
6) Which of the following conditions will typically demonstrate unrestricted MR DWI and ADC map?
a. epidermoid cyst
b. acute infarction
c. cerebral abscess
d. glioblastoma multiforme
e. viral encephalitis
d. glioblastoma multiforme
Diffusion-weighted MRI provides image contrast which is different from that provided by conventional MR techniques.
The sequence enables the measurement of net macroscopic water movement, which is anisotropic (varies in different directions) particularly in white matter.
Restricted diffusion is seen as high signal on DWI (which is a T2W image with signal degraded by diffusion) and low signal on the ADC map.
Restricted diffusion occurs in tissue that does not allow free movement of water molecules, such as areas of infection due to the high viscosity and cellularity of pus.
Similarly, epidermoid cysts are very cellular and so also show restricted diffusion, a feature that helps distinguish them from arachnoid cysts, which are fluid structures.
In stroke, restriction in water diffusion occurs within minutes after the onset of ischaemia. The basis of this change is not completely clear but is thought to be related to the cytotoxic oedema seen in ischaemic cells due to the impairment of the Na+/K+ ATPase pumps (which are very energy dependent), leading to loss of ionic gradients and a net translocation of water from the extracellular to the intracellular compartment, where water mobility is relatively more restricted.
13) What are the typical appearances of a pituitary microadenoma on early, contrast-enhanced T1W MR images?
a. focus of hypointensity within normal enhancing gland
b. focus of enhancement within normal, non-enhancing gland
c. lesion and normal gland enhance similarly
d. hyperenhancing focus within normal, mildly enhancing gland
e. not usually visualized on this sequence
a. focus of hypointensity within normal enhancing gland
Pituitary microadenomas are typically hypointense compared with the normal gland on unenhanced T1W images, and the diagnosis can usually be made without contrast.
Following contrast, the microadenoma does not initially enhance, and maximal contrast between enhancing normal gland and pituitary tumour is seen on dynamic images obtained within the first minute.
Contrast enhancement may therefore be useful inidentifying lesions that are not obviously hypointense on the unenhanced images.
However, contrast enhancement of the tumour relative to the normal gland may be seen on delayed (.20 min) images.
(Ped) 15 A 7 year old girl presents with lethargy, headaches and vomiting. CT shows a hyperdense lesion in the region of the posterior fossa. MR imaging confirms a midline vermian mass which abuts the roof of the 4th ventricle, displacing the brainstem anteriorly. The mass is hypointense on T2 and enhances homogeneously on T1 following i. v. contrast. What is the most likely diagnosis?
(a) Brainstem glioma
(b) Ependymoma
(c) Haemangioblastoma
(d) Medulloblastoma
(e) Pilocytic astrocytoma
(d) Medulloblastoma
All are examples of posterior fossa masses in children; other causes include meningioma, and epidermoid or dermoid cysts.
These features are typical for medulloblastoma (the differential diagnosis is an atypical teratoid / rhabdoid tumour).
Pilocytic astrocytomas are cystic with an enhancing peripheral nodule,
ependymomas arise from 4th ventricle floor and are hypodense on CT,
haemangioblastomas enhance avidly.
17) A mass is seen peripherally in the middle cranial fossa on MR of the brain. Which of the following imaging features favours an intra-axial rather than an extra-axial location?
a. buckling of the grey–white matter interface
b. expansion of the cortex of the brain
c. expansion of the subarachnoid space
d. medial displacement of pial blood vessels by the mass
e. the mass has a dural base
b. expansion of the cortex of the brain
Once the presence of a mass has been established, the radiologist must determine whether the mass is intra-axial (arising within the brain parenchyma) or extra-axial (arising outside the brain substance) in order to formulate an appropriate differential diagnosis.
An extra-axial mass characteristically causes buckling of the grey–white matter interface, expansion of the subarachnoid space at its borders, and medial displacement of the vessels in the subarachnoid space. A dural base is also a feature of an extra-axial mass.
Intra-axial masses characteristically cause expansion of the cortex of the brain but no expansion of the subarachnoid space, and pial vessels may be seen peripheral to the mass.
18) A 35-year-old woman presents with progressive deafness and tinnitus in the left ear. She undergoes MRI, which demonstrates a 2 cm mass at the left cerebellopontine angle. Which of the following features would favour a diagnosis of meningioma rather than vestibular schwannoma?
a. acute angle with the petrous bone
b. hyperintensity on T2W images
c. expansion of the internal auditory canal
d. presence of a dural tail
e. internal cystic degeneration and haemorrhage
d. presence of a dural tail
The most common causes of a cerebellopontine angle mass are vestibular schwannoma (also called acoustic neuroma) (75%), meningioma (10%) and epidermoid cyst (5%).
Features suggestive of a meningioma include a dural tail (thickening of enhancing adjacent dura resembling a tail extending from the mass), adjacent hyperostosis and an obtuse angle with the petrous bone (vestibular schwannomas make an acute angle).
Distinguishing features of schwannomas include extension into the internal auditory canal, causing expansion of the canal and flaring of the porusacousticus (bony opening of the internal auditory canal).
Meningiomas may show a small tongue of extension into the canal but usually no expansion.
Schwannomas undergo cystic degeneration and haemorrhage more commonly than meningiomas (particularly larger lesions), and may show very high signal on T2W images, which is unusual for a meningioma.
25) A 70-year-old man is referred for CT scan of the brain due to sudden onset of left-sided hemiparesis and clinical diagnosis of stroke. Unenhanced CT shows a rounded area of low attenuation in the right posterior frontal lobe with local gyriform swelling and sulcal effacement. Upon questioning, he reveals a history of lung resection for malignancy 18 months previously. Which of the following imaging investigations would you perform next?
a. no further imaging
b. CTof the thorax
c. CTof the thorax and abdomen
d. MRI of the brain
e. contrast-enhanced CTof the brain
e. contrast-enhanced CTof the brain
In this scenario, the low attenuation and surrounding changes most likely represent brain oedema.
This may be due to an evolving infarction or oedema around a metastatic deposit from the previous lung cancer.
Differentiation between the two will immediately affect patient treatment, as anti-platelet therapy for ischaemic stroke will increase the risk of haemorrhage from a metastasis and therefore should be with held if a metastatic deposit is suspected or diagnosed.
The primary factor in determining whether a lesion will enhance on CTafter administration of intravenous iodinated contrast is the integrity of the blood–brain barrier in that region of the brain substance.
A large molecule such as iodinated contrast would not be able to enter the brain unless the integrity of the barrier were compromised. The majority of aggressive tumours, including metastases, will disrupt this barrier, and so contrast enhancement will be seen in the solid component of these lesions. Acute infarction will typically not show areas of enhancement.
19) A 64-year-old woman presents with progressive headache and confusion. On CT, she is found to have multiple, well-defined, rounded, low-attenuation masses of varying sizes in both hemispheres at the grey–white matter junction. The masses demonstrate intense enhancement following intravenous contrast, and there is considerable surrounding oedema. Which of the following is the most appropriate next imaging investigation?
a. mammography
b. thyroid ultrasound scan
c. barium enema
d. renal ultrasound scan
e. chest radiograph
e. chest radiograph
Brain metastases are the most common intracranial tumours.
Six primary tumours account for 95% of all brain metastases.
Primary bronchial carcinoma is the most common (47% of cases), though squamous cell carcinoma rarely metastasizes to the brain. Other common primary tumours are breast carcinoma (17%), gastrointestinal malignancy (15%), renal cell carcinoma, melanoma and choriocarcinoma.
Metastases characteristically occur at the grey–white matter junction, are multiple in 66% of cases, and typically appear as hypodense masses that demonstrate solid or ring enhancement.
31) A 5-year-old boy undergoes CT of the brain for investigation of headaches, vomiting and ataxia. This demonstrates a welldefined, multilobulated, isodense mass within the fourth ventricle containing areas of punctate calcification. The mass is seen to extend out of the foramina of Luschka into the cerebellopontine angles. There is associated hydrocephalus. What is the most likely diagnosis?
a. metastasis
b. haemangioblastoma
c. juvenile pilocytic astrocytoma
d. medulloblastoma
e. ependymoma
e. ependymoma
Ependymomas most commonly arise in the floor of the fourth ventricle and are usually isodense. They have a greater incidence of calcification than other posterior fossa paediatric tumours; it is typically punctate and seen in 40–50% of cases.
A characteristic feature of ependymomas is their propensity to extend through and widen the foramina of Luschka and Magendie.
Juvenile pilocyticastrocytomas are the commonest paediatric infratentorial neoplasms and typically occur in the cerebellar hemispheres. They appear cystic with an enhancing mural nodule.
Medulloblastomas tend to be homogeneous hyperdense lesions located in the vermis, and the presence of calcification is uncommon.
Metastases are the commonest infratentorial tumour to occur in adults, but are uncommon in children.
Haemangioblastomas usually occur in young adults and are classically cystic masses with a solid mural nodule.
39) A 65-year-old, previously well man with a short history of headaches and behavioural change undergoes CT of the brain. This demonstrates an irregular, ill defined mass in the left frontal lobe extending across the corpus callosum to involve the right frontal lobe. The mass is of low attenuation and contains cystic areas, demonstrates ring enhancement following intravenous contrast, and has considerable surrounding oedema. What is the most likely diagnosis?
a. progressive multifocal leukoencephalopathy
b. glioblastoma multiforme
c. lymphoma
d. abscess
e. metastasis
b. glioblastoma multiforme
Glioblastoma multiforme is the most malignant form of astrocytoma. It occurs in older patients, and most commonly affects the deep white matter of the frontal lobes. Classic appearances are of an irregular, illdefinedhypodense mass with necrosis, haemorrhage and extensive surrounding white matter oedema. Ninety per cent of cases show enhancement, which may be diffuse, heterogeneous or ring like. Tumourspread is directly along white matter tracts, and commonly occurs across the corpus callosum to involve both frontal lobes (butterfly glioma).
Lymphomas also have a propensity to involve the corpus callosum but usually are slightly hyperdense due to a high nuclearto- cytoplasmic ratio.
Metastases may also involve the corpus callosumbut tend to be better defined and would be less likely in the absence of a known primary tumour.
Progressive multifocal leukoencephalopathy may involve the corpus callosum but occurs in immunocompromised patients.
Involvement of the corpus callosum is not usually a feature of abscesses.
46) A 17-year-old boy presents with headache and is found to have paralysis of upward gaze (Parinaud’s syndrome) on examination. MR scan of the brain identifies an abnormality. What is the most likely site of lesion?
a. thalamus
b. occipital lobe
c. optic chiasm
d. pineal gland
e. cerebellar vermis
d. pineal gland
Parinaud’s syndrome (also known as dorsal midbrain syndrome) is characterized by supranuclear paralysis of upward gaze. It results from injury or compression of the dorsal midbrain, in particular the superior colliculi, and is most commonly seen in young patients with tumours of the pineal gland or midbrain, with pineal germinoma being the most common lesion producing the syndrome.
Young women with multiple sclerosis and elderly patients with brain-stem stroke may also present with Parinaud’s syndrome.
47) A 28-year-old woman presents with a history of headaches and refractory temporal lobe epilepsy. CT of the brain demonstrates a mixed solid–cystic, intraparenchymal mass located peripherally in the right temporal lobe, which contains calcification and demonstrates faint enhancement following intravenous contrast. There is minimal surrounding oedema. What is the most likely diagnosis?
a. arachnoid cyst
b. ganglioglioma
c. epidermoid
d. meningioma
e. dysembryoplastic neuroepithelial tumour
b. ganglioglioma
Gangliogliomas are low-grade tumours with a good prognosis, generally occurring in patients under the age of 30. Typical presentation is with focal seizures, and ganglioglioma is the most common tumour seen in patients with chronic temporal lobe epilepsy. They are usually well-circumscribed, hypo- or isodense lesions in the temporal lobes. Calcification (30%) and cyst formation (.50%) are common features. There is usually minimal mass effect and surrounding oedema.
Meningiomas commonly calcify and have minimal surrounding oedema, but are extra-axial, and usually demonstrate intense uniform enhancement following intravenous contrast.
Dysembryoplastic neuro epithelial tumours are commonly associated with partial complex seizures, but usually occur before the age of 20, and characteristically appear as a soap-bubble, multicystic lesion, which may remodel the calvarium.
Epidermoids and arachnoid cysts are of CSF density, do not enhance with contrast and are extra-axial lesions.
50) A 44-year-old man presents with a long history of headaches and more recent onset of seizures. CT of the brain demonstrates an oval, well-defined, heterogeneous, hypodense mass containing large nodular clumps of calcification located peripherally in the right frontal lobe. The mass extends to the cortical margin, and there is erosion of the inner table of the skull. There is minimal surrounding vasogenic oedema. What is the most likely diagnosis?
a. meningioma
b. oligodendroglioma
c. astrocytoma
d. glioblastoma multiforme
e. ganglioglioma
b. oligodendroglioma
Oligodendrogliomas are slow-growing tumours, usually presenting in adults aged 30–50 years. They occur most commonly in the frontal lobe, and often extend to the cortex, where they may erode the inner table of the skull. Calcification is seen in 70% of cases, typically appearing as large nodular clumps. There is usually a relative absence of surrounding oedema.
Astrocytomas also usually appear as hypodense calcified lesions with little surrounding oedema, but calvarial erosion is not usually a feature.
Glioblastoma multiforme usually has considerable surrounding oedema and rarely calcifies.
Gangliogliomas show calcification in a third of cases but tend to occur in children and young adults, and have a predilection for the temporal lobes.
57) A 46-year-old man presents with headaches and visual disturbance and is found to have bitemporal hemianopia on visual field testing. CT of the brain demonstrates a multilobulated, heterogeneous, suprasellar mass containing cystic areas and rim-like calcification. Enhancement of the solid component is observed following intravenous contrast. What is the most likely diagnosis?
a. epidermoid
b. craniopharyngioma
c. pituitary macroadenoma
d. meningioma
e. Rathke’s cleft cyst
b. craniopharyngioma
Craniopharyngiomas are the most common suprasellar mass, predominantly occurring in the first and second decades, but with a second peak in the fifth decade. Presenting symptoms include headache secondary to hydrocephalus, bitemporal hemianopia (compression of the optic chiasm) and diabetes insipidus (compression of the pituitary gland).
Typical imaging features are calcification, cyst formation and enhancement that may be solid or nodular.
Meningiomas may arise in the suprasellar region and commonly demonstrate calcification but are generally not cystic.
Epidermoids may occasionally demonstrate rim calcification but rarely enhance following intravenous contrast.
Pituitary macroadenomas may undergo haemorrhage, resulting in heterogeneity that can cause confusion with craniopharyngioma, but this typically occurs in adolescence. Calcification in macroadenomas is infrequent.
Rathke’s cleft cysts are thin-walled, benign cysts arising in the anterior sellar or suprasellar region. They show no contrast enhancement and rarely calcify.
58) A 27-year-old, previously well man gives a history of positional headaches. He undergoes unenhanced CT of the brain, which demonstrates a well-defined, hyperdense,spherical lesion in the anterosuperior portion of the third ventricle, with asymmetrical enlargement of the lateral ventricles. What is the most likely diagnosis?
a. meningioma
b. colloid cyst
c. ependymoma
d. subependymal giant cell astrocytoma
e. choroid plexus papilloma
b. colloid cyst
Colloid cysts arise from the inferior aspect of the septum pellucidum and protrude into the anterior aspect of the third ventricle, where they may cause positional headaches and hydrocephalus due to transient obstruction at the foramen of Monro. They usually contain mucinous fluid, desquamated cells and proteinaceous debris, making them hyperdense on CT. On MR scan, the high protein content, as well as the paramagnetic effect of magnesium, copper and iron in the cyst, results in high signal intensity on T1W and T2W sequences in 60% of cases.
Meningiomas and ependymomas may also appear hyperdense, but location within the third ventricle is uncommon for both.
Subependymal giant cell astrocytoma is a benign tumour occurring in the region of the foramen of Monro, which may cause obstruction, but it is usually hypodense and is nearly always seen in association with tuberous sclerosis.
Choroid plexus papilloma predominantly occurs in children under 5 years of age, and location in the third ventricle is unusual.
@# 60) Which of the following is the most common radiation-induced CNS tumour?
a. ependymoma
b. oligodendroglioma
c. lymphoma
d. glioblastoma multiforme
e. meningioma
e. meningioma
Meningioma is the most common radiation-induced CNS tumour, and has been particularly associated with low-dose radiation treatment for tinea capitis.
For the diagnosis of radiation-induced meningioma to be made, the meningioma must arise in the radiation field, appear after a latency period of years and should not have been the primary tumour irradiated.
Radiation-induced meningiomas are more frequently multiple and have higher recurrence rates than non-radiation-induced tumours.
66) Following a large postpartum haemorrhage, a 25-year-old woman develops a severe headache and sudden visual field defect. What is the most likely diagnosis?
a. intracerebral haemorrhage
b. reversible posterior leukoencephalopathy
c. subarachnoid haemorrhage
d. Sheehan’s syndrome
e. vertebral artery dissection
d. Sheehan’s syndrome
Many of the acute neurological conditions of pregnancy occur with rising blood pressure.
Sheehan’s syndrome results from haemorrhage-induced hypotension causing pituitary infarction. Early on, this appears as an enlarged homogeneous pituitary with low T1 signal, high T2 signal and post-contrast ring enhancement. Later, there is an empty sella. Clinical manifestations include visual field loss, headache, ophthalmoplegia and pituitary dysfunction (diabetes insipidus).
Reversible posterior leukoencephalopathy produces cortical blindness, headaches, confusion and seizures. Those affected are often taking immunosuppressant treatment. Imaging features can be identical to eclampsia, peripartum cerebral angiopathy and hypertensive encephalopathy, but with a posterior predominance. On CT, there is low attenuation change. On MRI, there is high signal on T2W/FLAIR images. ADC maps can differentiate between likely reversible vasogenic oedema (high signal on ADC map showing unrestricted diffusion) and cytotoxic oedema (low signal due to restricted diffusion), which is more likely to progress to infarct.
Microangiopathic haemolytic anaemias, such as thrombotic thrombocytopenic purpura and haemolytic uraemic syndrome, give widespread ischaemia/infarction and haemorrhagic transformation. There is no increased risk in pregnancy of vasculitis such as systemic lupus erythematosus, Takayasu’s syndrome or Moyamoya syndrome.
Arteriovenous malformation is no more likely to bleed in pregnancy, but there is an increased risk with arterial aneurysms. Haemorrhage, sepsis and pulmonary embolism cause hypotension that can cause watershed infarction as well as Sheehan’s syndrome.
72) A 23-year-old man presents with acute headache. Unenhanced CT of the brain demonstrates a heterogeneous mass at the inferior cerebellar vermis. It is predominantly of fat attenuation with areas of calcification and does not enhance following administration of intravenous contrast. Multiple droplets of fat attenuation are noted throughout the subarachnoid space. What is the most likely diagnosis?
a. lipoma
b. arachnoid cyst
c. dermoid
d. epidermoid
e. teratoma
c. dermoid
Epidermoids and dermoids are congenital lesions resulting from inclusion of ectodermal elements during closure of the neural tube. Both have a squamous epithelial lining and produce keratin, but dermoids contain both ectodermal and mesodermal elements (hair follicles, sweat and sebaceous glands), while epidermoids contain only ectodermal elements.
Epidermoids are lobulated masses, usually located off the midline, which compress adjacent structures such as cranial nerves, and tend to have appearances on CTand MR scan following that of CSF.
Dermoids are usually midline in location and cause symptoms by obstruction of CSF pathways or by rupture and leakage of fat contents, causing chemical meningitis. They have appearances on CT and MR scan following that of fat, and are often heterogeneous with areas of calcification and other soft-tissue components. This heterogeneity helps to distinguish a dermoid from a lipoma.
Arachnoid cysts are of CSF density, but may be distinguished fromepidermoids on DWI, where they do not show evidence of water restriction.
Teratomas are composed of ectodermal, mesodermal and endodermal elements, and also appear heterogeneous with areas of fat, calcification and cystic components, but these lesions occur most commonly in the pineal and suprasellarregions.
86) A 27-year-old female presents with emotional lability and headaches. MRI of the brain demonstrates a well-defined mass in the pericallosal region. The mass is hyperintense on T1W images and demonstrates no enhancement with intravenous gadolinium. There is associated agenesis of the corpus callosum. What is the most likely diagnosis?
a. dermoid
b. lipoma
c. interhemispheric arachnoid cyst
d. epidermoid
e. lymphoma
b. lipoma
Intracranial lipomas appear as well-circumscribed masses of fat density on CTwith occasional rim calcification. On MR scan, characteristic appearances are of hyperintensity on T1W images, with chemical shift artefact or signal suppression on fat-saturated sequences.
Approximately 30% of intracranial lipomas occur in the pericallosal region, and there is a high incidence of associated congenital anomalies, most commonly agenesis of the corpus callosum, but also encephalocele and cutaneous frontal lipomas.
Interhemispheric arachnoid cysts may occur in association with agenesis of the corpus callosum, but they are of CSF density and, like epidermoids, appear hypointense on T1W images.
Dermoids have signal characteristics following those of fat, but are usually more heterogeneous and not associated with callosal anomalies.
Lymphoma may involve the corpus callosum but appears isoorhypointense on T1W images.
(Ped) 94) A 15-year-old boy presents to accident and emergency with signs of meningitis but no pyrexia. CT and MRI show a retroclival midline cystic tumour with localized mass effect. Which feature would support the diagnosis of a dermoid rather than an epidermoid cyst?
a. restricted diffusion on DWI
b. no enhancement with intravenous gadolinium on MRI
c. multiple septations on either modality
d. focal low attenuation on CT
e. well-defined calcifications on CT
d. focal low attenuation on CT
Dermoid and epidermoid cysts are ectoderm-lined congenital inclusion cysts. They may not present until early adulthood due to slow growth (particularly epidermoids).
Epidermoids contain only squamous epithelium whereas dermoids contain hair, sebaceous and sweat glands, and squamous epithelium. Unlike teratomas, neither is a true neoplasm.
Clinical presentation is often with chemical meningitis from rupture of fatty contents.
Epidermoids usually have imaging characteristics similar to water and can be differentiated from arachnoid cysts by restricted diffusion on DWI.
Attenuation varies according to the keratin:cholesterol ratio and therefore can be similar to fat but is usually homogeneous.
The cyst wall is very thin and is often not visible in epidermoids, and areas of calcification can infrequently be seen.
Dermoids may appear more complex but are still unilocular. The wall may be thicker and calcification is more frequent. The sebaceous lipid material in a dermoid has attenuation and signal intensity characteristics of fat on CT (low attenuation) and MR (high signal on T1).
‘White epidermoids’ with high signal on T1 may be seen rarely; they are due to haemorrhage or a high fat content. However, the latter usually produces a homogeneous fat signal as opposed to dermoids, where the appearances are more heterogeneous due to the increased complexity of contents.
99) A 21-year-old man presents with acute headache. He undergoes CTof the brain, which demonstrates a well-circumscribed, lobulated, partially cystic, calcified mass in the frontal horn of the left lateral ventricle, attached to the septum pellucidum. There is acute blood seen layering in the left lateral ventricle and mild hydrocephalus.
What is the most likely diagnosis?
a. choroid plexus papilloma
b. colloid cyst
c. intraventricular oligodendroglioma
d. central neurocytoma
e. subependymoma
d. central neurocytoma
Central neurocytomas (also known as intraventricular neurocytomas)are benign tumours of the lateral and third ventricles usually presenting in adults aged 20–40 years.
They frequently calcify (69%) and contain cystic spaces.
Attachment to the septum pellucidum is a characteristic feature.
Lesions appear isointense to grey matter on all MR sequences and show mild-to-moderate contrast enhancement.
Central neurocytomas were previously frequently mistaken for intraventricular oligodendrogliomas, which have very similar imaging features but are actually quite rare.
In addition, neurocytomas undergo haemorrhage into the tumour or ventricle more frequently, helping to distinguish the two.
Colloid cysts arise within the third ventricle, and rarely calcify.
Subependymomas may arise in the lateral ventricles with an attachment to the septum pellucidum, and cyst formation and calcification may be seen in large tumours. However, most occur in patients over 40 years of age.
Choroid plexus papillomas generally occur in children under 5 years of age.
100) A 2-year-old boy presents with involuntary saccadic eye movements (opsoclonus) and myoclonus of the trunk and limbs. What are the most likely findings on MRI of the brain?
a. normal appearances
b. cystic lesion in the posterior fossa with enhancing mural nodule
c. cerebellar atrophy
d. central symmetrical lesions in the pons of high signal intensity onT2W images
e. caudally displaced brain stem and fourth ventricle with tonsillarherniation
a. normal appearances
Opsoclonus–myoclonus syndrome is characterized by opsoclonus incombination with myoclonus of the trunk, limbs or head. It may be idiopathic or occur as a paraneoplastic syndrome, when it may follow are lapsing–remitting course.
In adults, it is most commonly associated with breast and squamous cell lung carcinoma, while in children it is associated with neuroblastoma.
The syndrome usually precedes diagnosis of the underlying malignancy, and in children should prompt investigation to identify an underlying neuroblastoma.
MIBG whole-body scintigraphy may be helpful in identifying occult disease if conventional imaging is negative. MR scan of the brain is usually normal.
3 A 76 year man presents with right-sided weakness. There is a low-attenuation lesion in the left basal ganglia. An MRI is arranged for further evaluation. Which feature would suggest a high-grade neoplasm rather than an infarct?
(a) Involvement of both cerebral cortex and juxtacortical white matter
(b) Gyriform enhancement
(c) Low signal on an apparent diffusion coefficient image
(d) Elevated choline on magnetic resonance spectroscopy
(e) Cytotoxic oedema
(d) Elevated choline on magnetic resonance spectroscopy
MR spectroscopy interrogates the chemical environment of intracerebral lesions: elevated choline is associated with high cellular turnover as found in neoplasms.
Tumours are often centred upon white matter with relative sparing of the overlying cortex.
Gyriform enhancement is unusual in neoplasms unless there is meningeal disease.
In the acute stage, an infarct will demonstrate restricted diffusion: high signal on the DWI image and low signal on the ADC image.
Cytotoxic oedema is typical of infarcts, whilst vasogenic oedema is typical of neoplasms.
7 A patient has radiotherapy after resection of his prirpary brain tumour. There is a change in his neurological symptoms. Which imaging feature would be more supportive of tumour recurrence rather than radiation injury?
(a) Low relative cerebral blood volume on CT perfusion imaging
(b) Decreased activity on Thallium SPECT imaging
(c) Decreased amplitude of the choline peak on MR spectroscopy
(d) High signal on MR FLAIR imaging
(e) Decreased amplitude of the N-acetyl-aspartate peak (NAA) on MR spectroscopy
(e) Decreased amplitude of the N-acetyl-aspartate peak (NAA) on MR spectroscopy
8 A CT reveals an intra-axial cerebral mass.Which of the following is the most likely diagnosis?
(a) Haemangioblastoma
(b) Haemangiopericytoma
(c) Meningioma
(d) Leptomeningeal lymphoma
(e) Nasopharyngeal carcinoma
(b) Haemangiopericytoma
Haemangiopericytoma is the only intra-axial mass listed.
15 A 5 year old presents with symptoms of raised intracranial pressure and ataxia. A CT examination reveals hydrocephalus and a posterior fossa mass which comprises a cyst and mural nodule.Given the mbst likely diagnosis, which of the following isincorrect?
(a) Surrounding vasogenic oedema is common
(b) Surgical resection is the treatment of choice
(c) Intense enhancement is typical
(d) Precocious puberty is associated
(e) Disseminated disease is rare
(a) Surrounding vasogenic oedema is common
A pilocytic astrocytoma is the most likely diagnosis.
This is the most common paediatric glioma, and the characteristic appearance is of acyst with an intensely enhancing mural nodule.
Surrounding oedema is rare.
40% of patients with both NF-1 and an optic pathway gllioma also suffer from precious puberty.
@# 26 An elderly man is admitted for assessment of focal neurological symptoms. An incidental supratentorial cystic lesion is demonstrated. Which of the following features would make the diagnosis of subdural hygroma, rather than arachnoid cyst, more likely?
(a) Isointense to CSF on T1W MR imaging
(b) Mass effect
(c) Isointense to CSF on T2W MR imaging
(d) Flattened sulci
(e) Bony remodeling
(e) Bony remodeling
Scalloping of the adjacent bone, possibly through transmitted pulsations, is often seen in arachnoid cysts. This is never seen in subdural hygromas, but can be seen with epidermoid cysts or porencephaly.?
29 An intra-cranial cyst is seen on MR imaging. What feature would support the diagnosis of arachnoid cyst rather than an epidermoid?
(a) Absence of enhancement
(b) Irregularity
(c) Iso-intense to CSF on DWI
(d) Cerebello-pontine angle location
(e) Calcification
(c) Iso-intense to CSF on DWI
The content of an arachnoid cyst has the same characteristics as CSF on all MR imaging sequences.
43 An elderly patient presents with confusion. A CT head reveals a lesion involving the corpus callosum and invading both frontal lobes. There is enhancement of the lesion periphery after the administration of intravenous contrast meaium.What is the most likely diagnosis?
(a) Abscess
(b) Radiation necrosis
(c) Meningioma
(d) Infarction
(e) Glioblastoma multiforme
(e) Glioblastoma multiforme
A ring-enhancing lesion that crosses the midline may represent, amongst other conditions, a glioblastoma multiforme (‘a butterfly glioma’), astrocytoma or lymphoma. Abscesses rarely cross the midline. An infarct is less likely as the above distribution does not correspond to a single arterial territory.
50 A CT head demonstrates a dilated lateral and third ventricle with a normal sized fourth ventricle. Which of the following would most likely account for this appearance?
(a) Colloid cyst
(b) Pinealoma
(c) Tonsillar herniation
(d) Choroid plexus papilloma
(e) Basilar impression
(b) Pinealoma
The pattern of dilatation is consistent with obstruction at the level of the aqueduct - of the options listed, a pinealoma is most likely to cause obstruction at this level.
11 A patient presents with sensorineural hearing loss. A cerebellopontine angle mass is demonstrated on MR imaging. Which of the following features support a diagnosis of schwannoma over menigioma?
(a) High signal intensity relative to grey matter on T2W imaging
(b) Enhancement with i. v. gadolinium
(c) Calcification
(d) Unilateral lesion
(e) Medurally based lesion
(a) High signal intensity relative to grey matter on T2W imaging
Schwannomas are the most common CPA mass.
The epicentre of the lesion is typically in the epicenter of the internal auditory canal, typically causing a >2 mm difference in canal diameter on the affected side.
Extension into the CPA causes an ‘ice cream cone’ appearance.
On MR imaging, the lesion is iso-intense on T1W, hyper-intense on T2W and has dense enhancement (however, meningiomas also typically enhance).
Ca is not typical.
20 A patient presents with gradual onset of sensory symptoms affecting the right hand. CT reveals a superficial mass within the fronto-parietal region. Which imaging feature would not support the diagnosis of menigioma?
(a) Inward bulging of the grey-white junction
(b) Surrounding oedema
(c) Hyperdense on unenhanced images
(d) Enhancement with intravenous contrast medium
(e) lntralesional haemorrhage.
(e) lntralesional haemorrhage.
Only 1 % of meningiomas are associated with internal haemorrhage.
Regarding the other characteristics: the inward bulging of the grey white junction is suggestive of an extra-axial lesion, such as a meningioma;
60% of meningiomas are associated with oedema;
meningiomas are typically hyperdense on unenhanced CT imaging and are seen to enhance with i. v. contrast medium.
21 A 45 year old female presents with facial pain and abnormal eye movements. A cerebellopontine angle lesion is identified on MR imaging. Which feature would not be consistent with an epidermoid tumour?
(a) Iso-intense to CSF on T1W Imaging
(b) Low signal on DWI
(c) Heterogeneous signal on FLAIR
(d) Lack of 1Efnhancement
(e) Low signal on balanced sequence/ true FISP
(b) Low signal on DWI
Epidermoid tumours are typically iso-intense to CSF on T1 and T2W imaging, with high signal on diffusion weighted sequences and heterogeneous signal on FLAIR imaging. They do not typically enhance.
26 A female patient is seen in the endocrine clinic and a pituitary microadenoma is suspected. Regarding the imaging of the pituitary gland, which of the following is an abnormal appearance?
(a) High signal in the posterior pituitary on T1 W
(b) Intermediate signal intensity in the posterior pituitary on T2W
(c) Enhancement of the posterior pituitary on T1 W after gadolinium administration
(d) Convex superior margin of the pituitary gland in pregnant subjects
(e) High signal in the anterior pituitary on T2W
(e) High signal in the anterior pituitary on T2W
On T1W imaging, the anterior pituitary is typically iso-intense and the posterior pituitary hyperintense; on T2W imaging, both the anterior and posterior pituitary are typically iso-intense. The gland is normally flat or concave superiorly, but may be convex in pregnancy.
29 An MRI brain is performed and a lesion is seen in the suprasellar region. Which of the following imaging characteristics is not typical?
(a) Craniopharyngioma - calcification and nodular enhancement
(b) Epidermoid - isointense to CSF on T1 W and T2W
(c) Tuber cinerum - isointense to grey matter on T1W
(d) Schwannoma - T1W hypointensity and marked enhancement with i. v. gadolinium
(e) Rathke’s cleft cyst - T1W hypointensity and lack of enhancement with i. v. gadolinium
(e) Rathke’s cleft cyst - T1W hypointensity and lack of enhancement with i. v. gadolinium
A Rathke’s cleft cyst is typically hyperintense on T1W, and has smooth peripheral enhancement with intravenous contrast medium.
31 An adolescent undergoes MR imaging and an incidental suprasellar mass is found. What feature would suggest a diagnosis of craniopharyngioma rather than a Rathke cleft cyst?
(a) Absence of calcification
(b) Predominantly high signal on T1 W imaging
(c) Smooth contour
(d) Homogeneous signal intensity
(e) Nodular enhancement
(e) Nodular enhancement
A craniopharyngioma would typically be seen as a cyst with a mural nodule.
Calcification is present in 90% of cases in the younger age group.
Both craniopharyngiomas and Rathke cleft cysts have variable signal intensities on MR imaging, but most commonly craniopharyngiomas have a low signal on T1W imaging.
The enhancement pattern is typically ‘solid’ or ‘nodular’, as opposed to the’rim-like’ pattern seen in Rathke cleft cysts.
@# 47 A 40 year old man presents with a seizure and a CT head reveals an intracranial lesion. An oligodendroglioma is suspected. Which feature would be least expected with this diagnosis?
(a) Ill-defined enhancement
(b) Cystic degeneration
(c) Absence of oedema
(d) Calcification
(e) Hyperdense on unenhanced imaging
(e) Hyperdense on unenhanced imaging
Oligodendrogliomas are slowly growing gliomas, most commonly located in the frontal lobes.
Large nodular calcification is present in approximately 90% of cases.
Cystic degeneration, ill-defined enhancement and a lack of oedema are all common.
Over 80% are either hypo- or iso- dense on unenhanced CT imaging.
53 A patient has a glioma resected and the post-surgical tumour bed is examined by CT imaging. Images are acquired both before and after the administration of i. v. contrast medium. Which of the following features would lead one to suspect that there is residual tumour?
(a) Linear enhancement around the pre-operative tumour bed
(b) Enhancement within the pre-operative tumour bed, 1 day after surgery
(c) Enhancement within the pre-operative tumour bed, 4 days after surgery
(d) Evidence of haemorrhage
(e) Dural enhancement
(b) Enhancement within the pre-operative tumour bed, 1 day after surgery
Within the first 2 days, enhancement within the pre-operative tumourbed should be regarded as suspicious of incomplete resection.
After this time, it is common for enhancing granulation tissue to develop.
Dural enhancement is a normal post-operative finding.
54 An adolescent undergoes MR imaging after having a number of seizures. A mass is demonstrated within the periphery of the right temporal lobe. The lesion contains a number of cysts. There is no surrounding oedema and the mass does not enhance after the adminstration of i. v. gadolinium. Which of the following is the most likely diagnosis?
(a) Desmoplastic infantile ganglioglioma
(b) Tanycytic ependymoma
(c) Oligodendroglioma
(d) High grade astrocytoma
(e) Dysembroplastic neuroepithelial tumour
(e) Dysembroplastic neuroepithelial tumour
DNETs are benign tumours arising from cortical gray matter, most commonly found in the temporal lobes.
They are characterised by the presence of multiple cysts and a lack of surrounding oedema.
Desmoplastic infantile gangliogliomas typically occur before the 2ndbirthday;
Oligodendrogliomas typically occur in 30-60 year olds.
55 A patient presents with a focal neurological deficit. CT imaging reveals multiple haemorrhagic foci. Which of the following features would be more consistent with haemorrhagic metastases, rather than haemorrhagic cerebrovascular malformations?
(a) Incomplete haemosiderin ring
(b) Surrounding oedema within the first week from symptom onset
(c) Central enhancement
(d) Calcification
(e) Lack of enhancement with i. v. contrast medium
(a) Incomplete haemosiderin ring
Haemorrhagic metastases typically have an incomplete or absent haemosiderin ring.
Calcification is rare.
Most commonly, there is either nodular, eccentric or ring enhancement.
This contrasts with haemorrhagic cerebrovascular malformations, which typically show minimal or central enhancement.
Surrounding oedema is present in both the acute/ subacute phase.
60 A 5 year old child presents with headache, vomiting and ataxia. On CT imaging, a high attenuation posterior fossa mass is seen to arise from the midline of the roof of the 4th ventricle. Given the most likely diagnosis, which of the following is incorrect?
(a) There is hydrocephalus in the majority
(b) The mass tends to be hyperintense on T1 W
(c) There is an association between enhancing pial nodules and seizures
(d) In children older than 3 years, the mass tends to be resected
(e) Recurrence is common
(b) The mass tends to be hyperintense on T1 W
The mass is most likely a medulloblastoma.
These tend to be iso-to hypointense on T1W.
Leptomeningeal metastases, seen as enhancing nodules, can cause seizures.
Hydrocephalus is present in 90% of cases.
62 A 50 year old patient presents with headache and visual disturbances. MR imaging is performed, and a mass is seen within the clivus. A chordoma is suspected. Which of the following features would be unusual for this diagnosis?
(a) Isointense to brain parenchyma on T1W
(b) Calcification
(c) Lack of tracer uptake on a 99mTc-MDP bone scintigram
(d) Lack of enhancement with i.v.gadolinium
(e) Some regions of low signal on T1 W
(d) Lack of enhancement with i.v.gadolinium
Chordomas originate from the remnants of the embryonic notochord, and may occur at any point along the neural axis.
The clivus is the second most frequently affected site.
The tumour is locally aggressive,calcified in approximately 50% (giving rise to areas of low T1W) and enhances.
They are typically isointense to brain parenchyma onT1W.
63 A patient presents with seizures. An MR of the brain reveals an apparent area of linear meningeal thickening adjacent to an intracranial tumour.Which of the following would make the description of this thickening as a ‘dural tail’ less appropriate?
(a) The adjacent tumour is an extra-axial
(b) The area of thickening does not enhance
(c) The thickening is only present on two contiguous 5 mm sections
(d) The adjacent tumour is intra-axial
(e) There is adjacent hyperostosis
(b) The area of thickening does not enhance
The 3 main criteria for the definition of a dural tail are:
presence on at least two contiguous 5 mm sections through the tumour (although now sections tend to be less than 5 mm thick);
the greatest thickness being adjacent to the tumour;
and enhancement being greater than the tumour itself.
Dural tails have classically been described in associationwith meningiomas, but can occur with other extra-axial and even intraaxial tumours.
73 You are shown a set of paediatric MR and CT head images in a teaching session. There is a well defined, lobulated mass within a dilated left lateral ventricle. There is hydrocephalus. It is hyperdense on CT and returns moderately high signal onT2W. There is intense contrast enhancement. What is the most likely diagnosis?
(a) Colloid cyst
(b) Meningioma
(c) Chorid plexus papilloma
(d) Ependymoma
(e) Giant cell astrocytoma
(c) Chorid plexus papilloma
The imaging characteristics are those of a choroid plexus papilloma.
Meningiomas are rarely intraventricular and most frequently occurin middle aged women.
Colloid cysts occur within the third ventricle.
Ependymomas typically arise from the floor of the fourth ventricle.
- A 20 year old male presents with the inability to gaze upwards. CT brain shows moderate hydrocephalus and a rounded mass adjacent to the tectal plate. The mass demonstrates marked homogeneous enhancement and is not calcified. MRI confirms a well-circumscribed, relatively homogeneous mass that is isointense to grey matter on T2-weighted imaging. The mass is hyperintense on contrast-enhanced T1-weighted imaging. What is the most likely diagnosis?
a. Germinoma
b. Teratoma
c. Pineoblastoma
d. Pineocytoma
e. Benign pineal cyst
1.a. Germinoma
Germinomas are germ-cell tumours arising from primordial germ cells.
They frequently occur in the midline, mostly in the pineal region but also in the suprasellar region.
In men, 80% of pineal masses are germ-cell tumours, in contrast to 50% in women.
They tend to occur in children or young adults (10–25 years old).
Symptoms depend on the location but the case describes Parinaud syndrome – paralysis of upward gaze due to compression of the mesencephalic tectum.
Germinomas may also cause hydrocephalus by compression of the aqueduct of Sylvius, thus patients may present with signs and symptoms of raised intracranial pressure.
Germinomas are a known cause of precocious puberty in children under the age of ten years.
They are malignant tumours and may show CSF seeding, making cytological diagnosis possible with lumbar puncture.
They are, however, very radiosensitive and show excellent survival rates.
Pineal teratomas tend to be heterogeneous masses containing fat and calcifications.
Pineoblastoma is a highly malignant tumour which is more common in children and usually has poor tumour margins.
- A 40 year old female is investigated for worsening headaches. CT shows a well-defined hyperdense globular lesion within trigone of left lateral ventricle. There is intense contrast enhancement. The most likely diagnosis is:
a. Choroid cyst
b. Ependymoma
c. Colloid cyst
d. Meningioma
e. Neurocytoma
2d. Meningioma
It is rare for meningiomas to occur intraventricularly (2–5% of all meningiomas) but they are the most common trigonal intraventricular mass in adulthood.
They tend to occur in 40 year old females.
- A 40 year old female presents with bitemporal hemianopia. CT brain shows a large, slightly hyperdense suprasellar lesion. The mass contains several lucent foci and there is bone erosion of the sella floor. There is enhancement post-contrast. T1-weighted MR imaging shows a predominantly isointense mass causing sella expansion and compression of the optic chiasm. The mass contains foci of low and high signal intensity. What is the most likely diagnosis?
a. Craniopharyngioma
b. Meningioma
c. Rathke’s cleft cyst
d. Giant internal carotid aneurysm
e. Pituitary adenoma
- e. Pituitary adenoma
Pituitary adenomas are divided into microadenomas (<1 cm) and macroadenomas (>1 cm).
Macroadenomas may present with endocrine dysfunction but are generally less active than microadenomas.
Thus, macroadenomas often present with symptoms of mass effect on the optic chiasm, or if there is lateral extension into the cavernous sinuses patients may present with other local cranial nerve palsies (III, IV, VI).
The differential diagnosis of a suprasellar mass includes (‘SATCHMO’):
Suprasellar extension of pituitary adenoma/sarcoid;
Aneurysm/arachnoid cyst;
TB/teratoma (other germ-cell tumours);
Craniopharyngioma;
Hypothalamic glioma or hamartoma;
Meningioma/ metastases (especially breast);
and Optic/chiasmatic glioma.
In this case, the sellar is widened and the floor is eroded suggesting the mass arises from the pituitary itself.
Low-density/low-intensity regions on CT/T1 MRI correspond to necrotic areas and high-signal foci on T1 MRI (found relatively frequently) represent areas of recent haemorrhage.
- A 35 year old male presents with ataxia and nystagmus. Blood tests reveal polycythaemia. CT head demonstrates a mass predominantly of CSF density in the posterior fossa. Subsequent MRI shows a largely cystic mass with an enhancing mural nodule. There is surrounding oedema but no calcification. The most likely diagnosis is:
a. Metastasis
b. Pilocytic astrocytoma
c. Haemangioblastoma
d. Choroid cyst
e. Ependymoma
- c. Haemangioblastoma
Haemangioblastoma is the most common primary intra-axial, infratentorial tumour in adults.
They are benign autosomal dominant tumours of vascular origin.
Approximately 20% occur with von Hippel–Lindau disease.
Other associations include phaeochromocytomas, syringomyelia and spinal cord haemangioblastomas.
About 20% of tumours cause polycythaemia.
Typical CT and MRI appearances are of a largely cystic mass with an enhancing mural nodule.
Oedema may be absent or extensive but calcification is rare.
Prognosis is 85% post-surgical five-year survival rate.
Infratentorial pilocytic astrocytomas may have very similar appearances to haemangioblastomas but some differences exist that can help differentiate the two.
Pilocytic astrocytomas predominantly occur in children and young adults, are generally larger (>5 cm) than haemangioblastomas, may contain calcifications and are not associated with polycythaemia.
(Ped) 6. A two year old girl presents with recurrent headaches, neck pain and vomiting. She is found to have kyphoscoliosis and café-au-lait spots. CT brain shows a mostly cystic mass within the right cerebellar hemisphere. There is some calcification. After contrast, there is enhancement of the cystic wall and strong enhancement of a mural nodule. The most likely diagnosis is:
a. Haemangioblastoma
b. Medulloblastoma
c. Metastasis
d. Pilocytic astrocytoma
e. Arachnoid cyst
- d. Pilocytic astrocytoma
Pilocytic astrocytoma is the most common paediatric glioma and accounts for approximately 85% of all cerebellar astrocytomas in children. Peak age is between birth and nine years old. (Over 80% of haemangioblastomas occur in adulthood.) They are associated with neurofibromatosis type 1 (café-au-lait spots and skeletal abnormalities).
The most common appearance is of a cyst with an intensely enhancing mural nodule (arachnoid cyst should be devoid of an enhancing nodule). They occasionally calcify (calcification is rare in haemangioblastomas). They run a relatively benign clinical course and almost never recur following surgical excision. There is no malignant transformation to anaplastic form.
(Ped) 17. A three year old boy presents with headaches and drowsiness. Examination reveals papilloedema. CT brain shows hydrocephalus and a mildly hyperdense homogeneous mass at the trigone of the left lateral ventricle. There is intense homogeneous enhancement post-contrast. On MRI the lesion is slightly hyperintense on T1 and slightly hypointense on T2-weighted imaging relative to white matter. Gadolinium injection confirms an intraventricular enhancing tumour island. The most likely diagnosis is:
a. Choroid plexus papilloma
b. Intraventricular meningioma
c. Ependymoma
d. Cavernous angioma
e. Pilocytic astrocytoma
- a. Choroid plexus papilloma
Eighty-six per cent of choroid plexus papillomas occur below the age of five years and they represent approximately 65% of choroid tumours.
Large aggregation of choroid produces CSF at an abnormal rate. This CSF overproduction contributes to hydrocephalus.
The most common location in children is the trigone of the lateral ventricle, the third ventricle is unusual and the fourth ventricle and cerebellopontine angle are more common in adults.
The tumour shows a smooth lobulated border and small calcifications are common. There is intense homogeneous enhancement.
Approximately 5% undergo malignant transformation to choroid plexus carcinoma.
Meningiomas are the most common trigonal intraventricular mass in adulthood.
They rarely occur under the age of 20.
Cavernous haemangiomas tend to occur in the third to sixth decades and are located in the subcortical cerebrum.
- A 40 year old man undergoes investigation for seizures. Head CT with and without contrast shows a large, round, sharply marginated, hypodense mass involving the cortex and subcortical white matter of the left frontal lobe. The mass contains large nodular clumps of calcification. There is surrounding oedema and ill-defined enhancement. MRI demonstrates a heterogeneous mass which is predominantly isointense to grey matter on T1 and hyperintense on T2. There is moderate enhancement. What is the most likely diagnosis?
a. Astrocytoma
b. Ganglioglioma
c. Ependymoma
d. Glioblastoma
e. Oligodendroglioma
- e. Oligodendroglioma
This is an uncommon glioma which usually presents as a large mass at the time of diagnosis.
Mean age is 30–50 years and they are more common in men than women.
The majority are located in the frontal lobe (_60%), although they can occur anywhere within the central nervous system, including the cerebellum, brainstem, spinal cord, ventricles and optic nerve.
Large nodular clumps of calcifications are present in up to approximately 90% of tumours.
Cystic degeneration and haemorrhage are uncommon.
Prognosis depends on the grade of the tumour. High-grade tumours show 20% ten-year survival whereas lowgradetumours show 46% ten-year survival.
Although astrocytomas can calcify, the calcifications are rarely large and nodular.
Glioblastomas rarely calcify.
Gangliogliomas are more common in the temporal lobes and deep cerebral tissues and the majority of them (80%) occur below the age of 30 years.
Ependymomas often demonstrate fluid levels due to internal haemorrhage.
- A 52 year old man presents following collapse. He was previously fit and well, describing only a relatively recent history of dull back pain. Initial CT scan of the head reveals a 1.5 cm hyperdense mass at the corticomedullary junction of the right cerebral hemisphere. The mass shows surrounding oedema which exceeds the volume of the lesion. There is strong lesional enhancement following contrast injection. What is the most likely diagnosis and subsequent management?
a. Glioblastoma multiforme with subsequent MRI of the brain
b. Prostatic cancer metastasis with digital rectal examination and measuring of the prostatic specific antigen
c. Acute haemorrhagic contusion with referral to the neurosurgeons for active monitoring
d. Renal cell metastasis with subsequent CT staging
e. Brain abscess with subsequent intravenous antibiotics
- d. Renal cell metastasis with subsequent CT staging
Brain metastases account for approximately a third of all intracranial tumours and are the most common intracranial neoplasm.
They characteristically occur at the corticomedullary junction of the brain and have surrounding oedema that typically exceeds the tumour volume.
Multiple lesions are present in approximately two-thirds of cases and should be searched for with administration of intravenous contrast.
Most are hypodense on CT unless haemorrhagic or hypercellular, hence the lesion in this case is haemorrhagic.
This lends itself to a differential of primary neoplasms which includes melanoma, renal cell carcinoma, thyroid carcinoma, bronchogenic carcinoma and breast carcinoma.
The history of back pain also suggests bone metastases.
Glioblastoma multiforme usually appears as an irregular, heterogeneous, low-density mass. Abscesses typically demonstrate ring enhancement post-contrast and may show loculation and specules of gas. The patient’s history describes collapse rather than headache or confusion following a fall, which moves the differential away from traumatic contusion. Although prostate cancer typically metastasises to the vertebrae, it is an uncommon primary site for brain metastases, especially as the lesion described is haemorrhagic.
50 A 45-year-old male was being investigated for reduced hearing on the left. The left internal auditory canal was expanded by a soft-tissue mass, which extended into the left cerebellopontine angle. There was minor calcification and the mass showed strongly enhanced following IV contrast. What is the most likely diagnosis?
a Meningioma
b Acoustic neuroma
C Epidermoid
d Metastasis
e Arachnoid cyst
50 Answer A: Meningioma
All the listed tumours occur within the cerebellopontine angle (CPA). Both meningiomas and acoustic neuromas can cause expansion of the internal auditory canal and enhance brightly with contrast. Meningioma is the most likely because there is calcification within the lesion described.
