2. Introduction
20-30% of cancers in children
2500-3000 new diagnoses/year
2nd most common neoplasm
Most occur before age 10 years
Tumors in infants - usually congenital.
Male/Female = 1.3/1.0
60-70% 5 year survival
3. Analysis of a Potential Brain Tumor
Age of the patient
Localization
- Intra-axial or extra-axial
- Compartment
- Crossing of the midline
CT and MR characteristics
- Calcification, fat and cystic
- T1, T2, DWI
- Contrast enhancement
Effect on surrounding structures
- Mass effect, edema
Solitary or multiple
Psuedotumor
4. Differentiating with Extra-axial lesions
CSF cleft sign
Displaced subarachnoid vessels
Cortical gray matter between mass and white matter
Displace and expand subarachnoid space
Broad dural space
Bony reaction
11. Astrocytoma
Most common pediatric brain tumor is astrocytoma.
– With half being found in the posterior fossa
Cerebellar astrocytoma make up 40% of pilocytic astrocytoma
Usually occur in the latter half of the first decade
– Mean age of 7 years old
– Rarely found in children less than 1 year of age
M:F = 2:1
Association with NF-1 - more indolent course
Symptoms:
– Increased ICP (headache, N/V, head size)
– Cerebellar deficits
Signs:
– Papilladema (84%)
– Ataxia
12. Astrocytoma (contd.)
Most commonly involve white matter, may involve cortex
CT:
- Hypodense or isodense
- mass lesion
- Calcification (10‐20%)
- Hemorrhage, cysts, calvarial erosion are very rare.
- No or very minimal enhancement
MRI:
- Hypointense on T1
- Hyperintense on T2 with
- discrete margins
- Minimal enhancement
13. 12 year old male child with headache and signs of ICT
15. Subependymal Giant cell Astrocytoma
benign tumours (WHO grade I)
seen almost exclusively in young patients with tuberous sclerosis (TS)
principally diagnosed in patients under 20 years of age
They can be either asymptomatic or symptomatic due obstructive hydrocephalus
16. Subependymal Giant cell Astrocytoma (contd.)
CT:
typically appears as an intraventricular mass near the foramen of Monro
they are usually larger than 1 cm
lesions are iso- or slightly hypoattenuating to grey matter
calcification is common and haemorrhage is possible
accompanying hydrocephalus may be present
often shows marked contrast enhancement (subependymal nodules also enhance)
MRI:
T1: heterogenous and hypo- to isointense to grey matter
T2: heterogenous and hyperintense to grey matter; calcified components can be hypointense
T1 C+ (Gd): can show marked enhancement
18. Pleomorphic xanthoastrocytoma
type of rare, low-grade astrocytoma (WHO Grade II)
found in young patients who typically present with temporal lobe epilepsy.
They are rare tumours accounting for only ~ 1% of primary brain tumours
almost invariably (98%) located supratentorially, typically located superficially (peripherally)
involve the cortex and overlying leptomeninges.
Approximately half are located in the temporal lobe
19. Pleomorphic xanthoastrocytoma (contd.)
CT:
usually present as cortical tumours with a cystic component
vivid contrast enhancement
no surrounding oedema; scalloping of the overlying bone.
A reactive dural involvement expressed by a dural tail sign can be found; Calcifications are rare.
MRI:
T1 - solid component iso to hypointense c.f. grey matter; cystic component low signal;
leptomeningeal involvement seen in over 70% of cases 2
T1 C+ (Gd) - solid component usually enhances vividly
T2 - solid component iso to hyperintense c.f. grey matter; cystic component high signal; little
surrounding vasogenic oedema
DSA - avascular on angiography
21. Oligodendroglioma
intracranial tumours that account for 5-25% of all gliomas and 5-10% of all primary intracranial
neoplasms
rare tumors in pediatric age group accounting for 0.5 to 1%
presentation is most frequently as a result of seizures
tumours are typically located supratentorially (85%), involving the white matter
most commonly found in the frontal lobes
22. Oligodendroglioma (contd.)
CT:
Tumours are of mixed density (hypodense to isodense).
High-attenuation areas within the tumour are likely from calcification (70-90% of ODs are
calcified)
Calcification can be located centrally, peripherally or they can be ribbon-like
The overlying skull may show pressure erosion
Only 50% of oligodendrogliomas show enhancement
MRI:
T1: typically hypointense
T2: typically hyperintense (except calcified areas); calcium seen as areas of "blooming"
T1 C+ (Gd): contrast enhancement is common but it is not a reliable indicator of tumour grade,
with only 50% of ODs enhancing to a variable degree, and usually heterogeneously
DWI – no diffusion restriction
24. Ganglioglioma
C/F - chronic temporal lobe epilepsy
Age- 10-20 years ( < 30 years)
Site- superficial hemisphere, temporal lobe
Three patterns:
- Circumscribed cyst + mural nodule- MC
- Solid tumor, expands gyri
- Infiltrating, poorly defined mass
25. Ganglioglioma (contd.)
CT - Findings are of a mass which is often non specific. General features include:
Iso or hypodense
frequently calcified ~35%
bony remodeling or thinning can indicate the slow growing nature of the tumour
enhancement is seen in approximately 50% of cases (involving the solid non-calcified component)
MRI:
T1 - solid component iso to hypointense
T1 C+ (Gd) - solid component variable contrast enhancement
T2 – a) hyperintense solid component b)variable signal in the cystic component depending on
amount of proteinaceous material or presence of blood products
c) peritumoral FLAIR/T2 edema is distinctly uncommon
T2* (GE/SWI) - calcified areas (common) will show blooming signal loss
27. Desmoplastic Infantile Ganglioglioma
form of desmoplastic infantile tumours
tend to have good prognosis
vast majority occur in children less than 1 year of age
M:F ratio of approximately 2:1
rapidly increasing head circumference is the most common presentation
Seizure activity is uncommon
The frontal and parietal lobes are the most common sites.
28. Desmoplastic Infantile Ganglioglioma (contd.)
CT:
manifests as an exceptionally large cerebral hemispheric mass composed of both cystic
and solid portions.
solid portion of these large masses is typically slightly hyperattenuating and typically
located along the cortical margin of the mass
these masses usually enhance intensely, and may demonstrate a dural tail
No calcification
MRI:
The solid portions typically have the following signal intensity:
T1 - isointense to brain parenchyma
T2 - isointense to brain parenchyma
T1 C+ (Gd) - intense enhancement; dural tail may be seen
30. Choroid Plexus Papilloma
uncommon, benign neuroepithelial intraventricular tumour (WHO grade 1)
account for approximately 1% of all brain tumours, 2-6% of all paediatric brain tumours
Approximately 85% of all choroid plexus papillomas occur in children under the age of 5 years.
Most common brain tumors in children under 2 years
Fourth ventricular tumors cause obstructive hydrocephalus with headache & ataxia
CPPs that arise in the foramen of Luschka or CP angle may cause cranial nerve palsies
The most common location is the lateral ventricle trigone ( atrium ) – 50 %
- fourth ventricle – 40 %
- third ventricle & cerebellopontine cistern – 10 %
The primary neoplasm sheds tumor & seeds the CSF pathways ( drop metastases )
31. Choroid Plexus Papilloma (contd.)
CT:
The tumours are usually well-defined lobulated masses
iso- or somewhat hyperdense compared to the adjacent brain. There is associated hydrocephalus.
They usually homogeneously enhance, demonstrating with an irregular frond-like pattern, resulting in a
cauliflower-like appearance.
Fine, speckled calcification is seen within the tumour in approximately 25% of cases
MRI:
T1 - typically isointense c.f. to adjacent brain. May be somewhat hypointense
T2 - iso to hyperintense, small flow-voids may be seen within the tumour
T1 C+ (Gd) - marked enhancement, tends to be homogenous
MRS - decreased NAA, increased Cho
Angiography: demonstrate intense vascular blush on angiography. Enlarged choroidal arteries may be seen
feeding the tumour, with shunting
33. Choroid Plexus Carcinoma
malignant neoplasm arising from the choroid plexus (WHO grade III)
significantly poorer prognosis than choroid plexus papilloma (CPP)
10 – 20 % of all choroid plexus neoplasms
Almost all occur in infants & children 2 – 4 years of age
Symptoms are due to hydrocephalus & less commonly due to parenchymal invasion
There is an association with Li-Fraumeni syndrome
They almost always arise in the lateral ventricles & infiltrate the adjacent brain parenchyma
34. Choroid Plexus Carcinoma (contd.)
CT:
choroid plexus carcinomas are heterogeneous and typically iso to hyperdense to grey matter
Calcification may be seen in 20-25% of cases.
Contrast enhanced is usually prominent but heterogeneous with areas of necrosis and cyst
formation evident.
MRI:
T1: iso- to hypointense
T2: iso- to hypointense with hyperintense necrotic areas
T2* GRE: blooming from calcifications/haemorrhage
T1 C+ (Gd): can show marked, heterogeneous enhancement.
The tumours may have CSF seeding
Differential diagnosis:
Choroid Plexus papilloma
Central neurocytoma
Choroid plexus meningioma
PNET
GBM
36. Central Neurocytoma
WHO Grade II neuroepithelial intraventricular tumour
typically seen in young patients (16-40 years of age), and generally have a good prognosis
accounts for less than 1% (0.25-0.5%) of intracranial tumours
symptoms of increased intracranial pressure, headaches being most frequent, or seizures
associated with sudden death secondary to acute ventricular obstruction
sudden presentation due to intraventricular haemorrhage
Variant – ganglioneurocytoma
Typical locations include:
- lateral ventricles around foramen of Monro (most common): 50%
- both lateral and 3rd ventricles: 15%
- bilateral: 15%
- 3rd ventricle in isolation: 5%
37. Central Neurocytoma (contd.)
CT:
Central neurocytomas are usually hyperattenuating compared to white matter
Calcification seen in over half of cases, usually punctate in nature
Cystic regions are frequently present, especially in larger tumours.
Contrast enhancement is usually mild to moderate.
Accompanying ventricular dilatation often present.
MRI:
T1 - isointense to grey matter, heterogenous
T1 + C - mild-moderate heterogeneous enhancement
T2/FLAIR - typically iso to somewhat hyperintense compared to brain
numerous cystic areas (bubbly appearance), many of which completely attenuate on FLAIR
Prominent flow voids may be seen
SWI – blooming
MRS – strong choline peak
39. Pineocytoma
relatively benign pineal parenchymal tumour (WHO grade I tumor)
relatively good prognosis
encountered at any age but mostly occur in young adults in the second decade of life
clinical presentation is mainly from obstructive hydrocephalus secondary to compression of the
tectum of the midbrain
compression of the superior colliculi can also lead to a characteristic gaze palsy, known as
Parinaud syndrome
40. Pineocytoma (contd.)
CT:
intermediate density, similar to adjacent brain
Pineal calcifications tend to be dispersed peripherally
MRI:
T1: isointense to brain parenchyma
T2:
solid components are isointense to brain parenchyma
areas of cystic change are common
sometimes the majority of the tumour is cystic
T1 C+ (Gd): solid components vividly enhance
42. Pineoblastoma
primitive neuroectodermal tumours (PNET) located in the pineal region
most agressive and highest grade tumour among pineal parenchymal tumours
typically found in young children, with both sexes being equally affected
well established association with hereditary retinoblastomas
Patients with bilateral retinoblastoma 5-15% develop midline (suprasellar or pineal)
neuroblastic tumours, referred to as trilateral retinoblastoma.
always associated with obstructive hydrocephalus
highly malignant tumours prone to CSF seeding
43. Pineoblastoma (contd.)
CT:
Large poorly defined masses (>4 cm)
Tendency to directly involve adjacent brain structures
The solid component tends to be slightly hyperdense compared to adjacent brain.
Classically, they are described as having peripherally disperse or "exploded" calcification
MRI:
T1- isointense to hypointense to adjacent brain
T2 - isointense to adjacent brain; areas of cyst formation or necrosis may be present
T1 C+ (Gd) - vivid heterogenous enhancement
DWI - restricted diffusion due to dense cellular packing
45. DNET
Dysembryoplastic neuroepithelial tumor- benign, focal, intracortical mass superimposed on
background of cortical dysplasia
vast majority are centered in cortical grey matter, arise from secondary germinal layers
C/F- longstanding partial complex seizures
Age- < 20 years
Site - temporal lobe ( amygdala/ hippocampus) 60%, frontal lobe 30%, caudate nucleus,
cerebellum and pons
46. DNET (contd.)
DNETs are typically predominantly cortical and well circumscribed tumours.
CT:
if cortical may scallop the inner table of the skull vault (44-60%), but no erosion
the cranial fossa can be minimally enlarged at times
calcification in ~30% (more common histologically)
low density; no enhancement
MRI:
T1 - generally hypointense c.f adjacent brain
T1 C+ (Gd) - may show enhancement in ~20-30% of cases; enhancement may be heterogeneous
or a mural nodule; focal punctate or ring enhancement- 20%
T2 - generally high signal; high signal 'bubbly appearance‘
FLAIR- hypo/ isointense with bright rim; no peritumoral edema
DWI- lacks restricted diffusion
48. Intracranial Germinoma
also known as dysgerminomas or extra-gonadal seminomas
tumours of young patients with a peak incidence of 10-12 years of age
account for 3-5% of paediatric intracranial tumours
most common tumour of the pineal region accounting for approximately 50% of all tumours
male to female ratio of 5-22:1
tend to occur in the midline, either at the pineal region (majority) or along the floor of the third
ventricle/suprasellar region
obstructive hydrocephalus and Parinaud syndrome
involvement on the pituitary infundibulum leads to diabetes insipidus (most common),
hypopituitarism (common) or optic chiasm compression or signs of intracranial hypertension.
49. Intracranial Germinoma (contd.)
CT:
Germinomas are soft tissue density masses
high cellularity results in a degree to hyperdensity compared to adjacent brain
typically seen filling and expanding the infundibular recess and supraoptic recess
subtle abnormal pituitary stalk enhancement and thickening
presence of calcification in the pineal region is a useful marker of an underlying tumour
MRI:
MRI demonstrates a soft tissue mass, typically ovoid or lobulated in contour, engulfing the calcified
pineal gland with the following signal characteristics
T1 - isointense or slightly hyperintense to adjacent brain
T2 - isointense or slightly hyperintense to adjacent brain; may have areas of cyst formation; may have
areas of haemorrhage (low signal); have a predilection to invade adjacent brain (oedema); central
calcification appears low signal (engulfed pineal gland)
T1 C+ (Gd): vivid and homogeneous
50. T1WI
T1 + C
T2WI FLAIR
Differential diagnosis:
• Pineocytoma
• Pineoblastoma
• Papillary tumor of pineal gland
• Astrocytoma of pineal gland
• Meningioma near pineal gland
51. Intracranial Teratoma
account for the largest proportion of fetal intracranial neoplasms
divided into two broad categories:
- intra- and extra-axial
Intra-axial teratomas present antenatally due to increasing head circumference; tend to occur
supratentorially
Extra axial teratomas usually present in childhood or early adulthood; commonly arise in the
pineal or suprasellar regions; obstructive hydrocephalus, Parinaud syndrome
52. Intracranial Teratoma (contd.)
CT:
Intracranial teratomas are often seen as large lesions at presentation
tumours typically demonstrating a mixture of tissue densities and signal intensity
demonstrate at least some fat and some calcification, which is usually solid / "clump-like"
They usually have cystic and solid components, contributing to an irregular outline.
Solid components demonstrate variable enhancement
MRI:
T1 - hyperintense components due to fat and proteinaceous/lipid rich fluid; intermediate
components of soft tissue; hypointense components due to calcification and blood products
T1 C+ (Gd) - solid soft tissue components show enhancement
T2 - again mixed signal from differing components
54. Hypothalamic Hamartoma
Rare congenital condition consisting of a mass of disorganized neuronal or glial tissue on or near
the hypothalamus.
The size varies from less than 1 cm to more than 3 cm.
These lesions can be pedunculated or sessile.
Present with precocious puberty, gelastic seizures,visual problems and behavioral problems
associated with Pallister-Hall syndrome which is a syndrome consisting of multiple
malformations, including polydactyly and imperforate anus.
Central precocious puberty is also frequently encountered in these children
small pedunculated growths contiguous with posterior hypothalamus, between the tuber
cinereum and mamillary bodies.
They fill the free space between the optic chiasm and pons and usually do not distort the
hypothalamus or other parts of the base of the brain unless they are very large.
55. Hypothalamic Hamartoma (contd.)
CT:
nodule of soft tissue iso-attenuating to grey matter
without calcification or contrast enhancement
MRI:
T1 - isointense to cerebral cortex
T1 C+ (Gd) - no contrast enhancement
T2 - iso- to hyperintense to cerebral cortex; the higher the proportion of glial cells, the higher the T2
signal
MRS - reduced NAA/Cr, increased myoinositol, increased Cho/Cr compared to the amygdala has also
been reported
Differential diagnosis:
Hypothalamic-chiasmatic glioma
57. Craniopharyngioma
Arise from squamous epithelial rests along the involuted hypophyseal- Rathke’s duct
3% of intracranial neoplasms.
15% of supratentorial and 50% suprasellar tumors in children
M>F
Bimodal age distribution- 1st- 5-15 yrs and 2nd peak- 4th-6th decade
Types- Adamantinomatous and papillary
59. Craniopharyngioma (contd.)
MRI:
Multilobulated, multicystic suprasellar masses.
T1WI - cystics areas may be isointense or have high or low SI as compared to brain
T2WI - both solid and cystic components tend to be hyperintense but cystic component tend
to have higher SI. Solid part has granular appearance on pre-contrast T1WI and may show
heterogenecity as a result of small cysts and calcification.
Post-contrast- solid part enhance heterogenously. Thin walls of cysts nearly always enhance
Papillary type - entirely solid. Heterogenous appearance and enhancement.
MRS - to differentiate from suprasellar astrocytoma which shows large Choline peak and
reduced but present NAA peak
61. Intracranial Lipoma
Lipoma are not true neoplasm, classified as choristomas ( mass of tissue that would be
histologically normal for an organ or body other than the site at which it is located)
ETIOLOGY- results from abnormal persistense/ maldifferentiation of meninx primitiva
GROSSLY- 2 Types
- Tubulonodular lipomas- are large bulky round/cylindrical masses.
Commonly ass.with corpus callosum dysgenesis, frontal lobe anomalies & cephaloceles
- Curvilinear lipomas- are thin posteriorly situated, curve around the splenium. Corpus callosum
is usually normal.
62. Intracranial Lipoma (contd.)
Incidence- 0.1-0.5% of primary brain tumours.
5% of corpus callosum tumors
Neither age nor gender related
Location- at or near midline- 80-95%. Common sites are pericallosal area, quadrigeminal,
interpeduncular, chiasmatic, sylvian cisterns, cerebellopontine angle.
CT- very low density mass(-50 to-100 HU), curvilinear or nodular calcification. With
ass.congenital malformations.
Show no enhancement
MRI- Hyperintense on both T1W & fast spin-echo T2WI. Low signal foci represent calcification,
traversing arteries or nerves.
Fat- suppression technique used to confirm diagnosis.
64. Rathke Cleft cyst
Etiology
- Primitive stomodeal (Rathke’s pouch) remnant
Pathology
Gross:
- Cyst with variable contents (serous, mucoid)
Microscopic:
- Columnar/cuboidal epithelium; goblet cells often present, squamous cells sometimes seen
Incidence
- <1% of nontraumatic intracranial masses; small cysts common at autopsy
65. Rathke Clef cyst (contd.)
Age and gender
- Any age but mostly adults 40 – 70 years; F:M = 2-3:1
Location
- 70% both infra/suprasellar; 25% to 25% intrasellar; <5% completely suprasellar
CT: 75% hypodense to brain; noncalcified; 50% rim (capsular)enhancement
MR: Most common = hyperintense to brain on T1WI, with variable signal on T2WI
Differential diagnosis:
Arachnoid cyst, noncalcified craniopharyngioma, cystic pituitary adenoma, inflamatory cyst
67. Epidermoid
Irregularly lobulated
Insinuating
Common in CP angle, 4th ventricle, supra & parasellar regions.
Intra cerebral < 10%
Incorporation during 4-5th week of development.
No dermal appendages & hair follicles.
Dermoids contain dermal appendages.
68. Epidermoid (contd.)
Similar to CSF on T1 & T2
High signal in case of white epidermoids
Incomplete nulling on FLAIR
DWI – Restriction
No enhancement, Thin enhancement at the periphery
25% may show rim enhancement
White epidermoid – More protein and debris ---- high signal on T1 & CT.
70. Dermoid
Incidence
- Uncommon (0.04% to 0.6% of primary brain tumors)
Age
- 30 to 50 years; slight male predominance
Location
- Midline
- Parasellar, frontobasal most common intra-cranial sites
- Vermis, 4th ventricle most common infra- tentorial sites
- Subarachnoid spread from ruptured cyst
71. Dermoid (contd.)
CT:
appear as well defined low attenuating (fat density) lobulated masses.
Calcifications may be present in the wall.
Enhancement is uncommon, and if present should at most be a thin peripheral rim.
Very rarely they demonstrate hyperdensity thought to be due to a combination of saponification,
microcalcification and blood products.
MRI:
Typically follow fat density on all sequences
No enhancement; extensive pial enhancement may be present in chemical meningitis due to
ruptured cyst
74. Pilocytic Astrocytoma
5-10% of all glioma
75% of cerebellar Astrocytomas are of the Pilocytic type
MC primary brain tumour in children
Slowly growing tumour
WHO Grade 1
Clinically aggressive but malignant transformation is uncommon
5 yr survival rate is 86-100%
Associated with NF-1 (Optic pathway, 15-21%)
Frequently causes obstructive hydrocephalus
Pilomyxoid astrocytoma is a variant (WHO grade 2 tumor), most commonly involves
hypothalamus and optic chiasm
75. Pilocytic Astrocytoma (contd.)
Cystic cerebellar mass with enhancing mural nodule
Enlarged optic nerve/chiasma/adjacent to 3rd ventricle/brainstem (dotted I sign)
Less than 10% - solid.
May enhance in a homogeneous or a heterogeneous fashion
Approximately 50% are simple cysts with a single mural nodule
No histological evidence of tumor is present in the cyst wall. Removal of the mural nodule in
this tumor variety may be sufficient for treatment.
About 40-45% consist of multilocular cysts In these cases, histologic evidence of tumor is
present in the cyst wall.
Contrast enhancement is strong
Calcification (10%)& Hemorrhage are rare
T1: iso to hypointense solid component compared to adjacent brain
T2: hyperintense solid component compared to adjacent brain
76. 7 year old male with c/o nystagmus and gait abnormality
79. Medulloblastoma
Medulloblastoma - posterior fossa
PNET - supratentorial
Pineoblastoma - pineal region
3% of brain tumors
15 – 20% of childhood malignant brain tumors
30 – 40% of childhood posterior fossa tumors
Typically occur in the posterior fossa (75%) 25% in lateral cerebellum
Age: 5-15y
M:F = 2:1
propensity to disseminate through CSF
- 1/3 with metastatic disease at diagnosis
- Can spread to lung, liver, BM, bone, LN’s – rare
80. Medulloblastoma (contd.)
CT - a heart or pear shaped hyperdense midline vermian mass abutting the roof of the fourth
ventricle, with perilesional oedema, variable patchy enhancement and hydrocephalus.
Brainstem -displaced anteriorly.
Cystic change, haemorrhage and calcification may be seen.
Typical features - seen in only 30 % of cases
Atypical features are common
- Cystic changes (65%)
- Isodense attenuation on NECT (3%) and abnormal contrast enhancement
86. Metastatic Medulloblastoma
Disseminated Medulloblastoma - 20- 50%
2/3rd to other CNS locations
1/3rd extra cranial primarily to bone(typically lytic)
Disseminated CSF metastasis coats the brain like frosting on cake ,giving rise to
ZUCKERGUSS ( sugar icing)
– Entire neuraxis should be scanned.
Metastasis along Virchow Robin spaces
88. Ependymoma
Third most common pediatric brain tumor
Mean age at diagnosis is 4‐6 years
– 1/3 of which are diagnosed before age 3.
Arise from the ependymal cells that line the ventricle of the brain and spinal cord
May have leptomeningeal spread of brain/spine, CSF at the time of diagnosis
NF2 patients commonly have spinal ependymomas not intracranial.
Can be seen with Li‐Fraumeni syndrome (p53) and Turcot syndrome (APC gene)
Presenting symptoms are – disequilibrium , nausea , vomiting & headache & signs are ataxia &
nystagmus
Location - 60 % are infratentorial - > 90 % are in fourth ventricle , medulla & cerebellopontine
angle cisterns make the remaining; 40 % are supratentorial – extraventricular loction more
common ( 2/3rd to 3/4th ) than intraventricular sites
89. Ependymoma (contd.)
Types:
Classic
Papillary
Myxopapillary - Conus medullaris or filum terminale of the spinal cord
Subependymoma – represent a transitional form between ependymoma & astrocytoma.
Ependymoblastoma- from primitive neuroepithelial precursor cell & shows ependymal
differentiation.
Clear Cell
Tanycytic
Giant Cell
Anaplastic
90. Ependymoma (contd.)
CT:
Most are isodense
50 % cases show calcification
Overt hemorrhage is uncommon
Mild to moderate inhomogenous enhancement is
seen in 70 % of cases
92. Ependymoma (contd.)
MRI:
The MR differentiation of ependymomas from other gliomas is related to their location &
morphology only.
The post fossa ependymoma is lobulated soft tissue mass that appears to form a cast or mold
of the fourth ventricle & extrudes through its outlet foramina into the adjacent subarachnoid
cisterns
The solid components are hypo – to isointense compared to brain on T1WI & hyperintense on
proton density & T2WI
The cystic portions are slightly hyperintense to CSF on T1WI & hyperintense to brain on T2WI
Intratumoral heterogeneity may represent necrosis , calcification , tumor vascularity or blood
degradation products
95. Differential diagnosis for ependymoma:
Medulloblastoma
Choroid plexus papilloma
Central neurocytoma
Pilocytic astrocytoma
96. Brainstem Glioma
Represent 10‐20% of all CNS tumors in children
Peak presentation at 7‐9 years
Classic triad of physical findings (all three seen in 1/3 of cas
es):
– Cranial nerve palsies, ataxia and Long tract signs
Types:
Diffuse intrinsic brainstem glioma
- Most commonly located in the Pons
- Account for 80% of brainstem tumors
Focal
Occupy less than 50% of brainstem subregion.
Often clearly distinguishable from surrounding brainstem.
Subtypes include dorsal exophytic, cervicomedullary and
midbrain
97. Brainstem Glioma (contd.)
CT:
Typically hypodense with little, if any, enhancement.
MRI:
Modality of choice
Hypointense on T1
Hyperintense on T2
Enhancement is variable and depends on the type and grade
of the tumor
– Diffuse intrinsic tumors rarely enhance.
Differential diagnosis:
Rhombencephalitis
ADEM
LCH
Tuberous sclerosis
NF 1
PNET
Ependymoma
99. Atypical Teratoid Rhabdoid Tumor
uncommon malignant intracranial tumors, representing only 1.3% of primary CNS tumors in the
pediatric population (WHO Grade IV tumour)
vast majority of cases occurs in young children less than two years of age
can occur anywhere in the central nervous system (CNS) including the spinal cord.
infratentorial: ~50%
- cerebellum (most common), brainstem
supratentorial
- cerebral hemispheres, pineal gland region, septum pellucidum and hypothalamus
100. ATRT (contd.)
CT :
often isodense to gray matter
may demonstrate heterogeneous enhancement
calcification is common
may show associated obstructive hydrocephalus
MRI:
Can show necrosis, multiple foci of cyst formation and sometimes haemorrhage:
T1: iso- to slightly hyperintense to grey matter (haemorrhagic areas can be more hyperintense)
T2: generally hyperintense (haemorrhagic areas can be hypointense)
T1 C+ (Gd): heterogeneous enhancement
MRS
- Cho: elevated
- NAA: decreased
Differential diagnosis for ATRT:
Supratentorial PNET
Intracranial teratoma
Medulloblastoma
Choroid plexus carcinoma
Malignant glioma
103. Hemangioblastoma
Presentation- headache, disequilibrium, dizziness
Age- 40-60 years
VHL associated occur in younger age group
IMAGING FINDINGS:
Best diagnostic clue - intraaxial posterior fossa mass with cyst, enhancing mural nodule abutting
pia
Location - cerebellar hemisphere- 80%
- vermis-15%, medulla & 4th ventricle- 5%
104. Hemangioblastoma (contd.)
CT:
low density cyst + isodense nodule
intensely enhancing nodule
Cyst wall doesn’t enhance
MRI:
T1WI- nodule isointense to brain, cyst slightly hyperintense compared to CSF
T2WI- both nodule & cyst are hyperintense
Post contrast- intensely enhancing nodule
MRS
- Raised lipid and choline
- Absent NAA and lactate
Differential Diagnosis:
Pilocytic astrocytoma
AVM
Ependymoma
Medulloblastoma
105. 16 year old male with symptoms and
signs of raised ICT
106. Acoustic Schwannoma
Can be unilateral or bilateral.
- If there are bilateral acoustic schwannomas this is diagnostic for NF2
-Unilateral Acoustic schwannoma and a first degree relative with NF2 is diagnostic of NF2
Can be sporadic or associated with NF2.
– Sporadic variety is very rare in pediatric population
Account for 0.8% of pediatric brain tumors
NF2 associated schwannomas present with auditory complaints only 30% of the time.
As opposed to the sporadic variant, NF2 associated schwannomas grow faster and have
increased invasion of the nerve
107. Acoustic Schwannoma (contd.)
CT:
show erosion and widening of the internal acoustic canal
density of these tumours on non-contrast imaging is variable
Contrast enhancement is present, but can be underwhelming, especially in larger lesions with
cystic components
MRI:
T1 - slightly hypointense cf. adjacent brain (63%); isointense cf. adjacent brain (37%); may contain
hypointense cystic areas
T2 - heterogeneously hyperintense cf. to adjacent brain; cystic areas fluid intensity and may have
associated peritumoural arachnoid cysts 3
T1 C+ (Gd) - contrast enhancement is vivid but heterogeneous in larger tumors
109. Intracranial Teratoma
account for the largest proportion of fetal intracranial neoplasms
divided into two broad categories:
- intra- and extra-axial
Intra-axial teratomas present antenatally due to increasing head circumference; tend to occur
supratentorially
Extra axial teratomas usually present in childhood or early adulthood; commonly arise in the
pineal or suprasellar regions; obstructive hydrocephalus, Parinaud syndrome
110. Intracranial Teratoma (contd.)
CT:
Intracranial teratomas are often seen as large lesions at presentation
tumours typically demonstrating a mixture of tissue densities and signal intensity
demonstrate at least some fat and some calcification, which is usually solid / "clump-like"
They usually have cystic and solid components, contributing to an irregular outline.
Solid components demonstrate variable enhancement
MRI:
T1 - hyperintense components due to fat and proteinaceous/lipid rich fluid; intermediate
components of soft tissue; hypointense components due to calcification and blood products
T1 C+ (Gd) - solid soft tissue components show enhancement
T2 - again mixed signal from differing components
Editor's Notes
30-35% of all brain tumors, virtually seen in any compartment
Types in low grade – fibrillary, gemistocytic and protoplasmic
DWI can be used to help differentiate ODs (generally lower grade) from astrocytomas (generally higher grade); astrocytomas have higher ADC values probably because of their higher cellularity
Young patient with protracted h/o seizures & well defined cystic tumor containing calcification in periphery of temporal lobe with little or no mass effect strongly consider Ganglioglioma.
Axial T1-weighted MR image shows a large, lobulated mass centered in the region of the choroid plexus glomus of the left lateral ventricle. There is also entrapment of the posterior portion of this ventricle by the mass.
Axial T2-weighted MR image shows marked hypointensity within the mass.
Contrast-enhanced axial T1-weighted MR image shows intense homogeneous enhancement of the mass.
a) Axial CT image shows a lobulated, hyperattenuated, intraventricular mass within the posterior portion of the lateral ventricle. There is surrounding vasogenic edema (arrows).
(b) Axial T1-weighted MR image shows the lobulated mass with heterogeneous signal intensity.
(c) On an axial T2-weighted MR image, the mass is slightly hyperintense compared with the white matter. The vasogenic edema is more conspicuous than in a. Circumferential marked hypointensity (arrowheads) suggests hemosiderin deposition.
d) Contrast-enhanced axial T1-weighted MR image shows intense but heterogeneous enhancement within the mass. At surgery, the ventricular wall was transgressed by the mass, and histologic analysis confirmed choroid plexus carcinoma.
The CT finding of hyperdensity and MRI finding of T2 hypointensity, supported by the presence of restricted diffusion on diffusion-weighted imaging,(typical feature) are the most reliable observations in differentiating medulloblastoma (and atypical rhabdoid tumour which on imaging appears identical to medulloblastoma) from Ependymoma or other posterior fossa tumours.
MRI demonstrates a mass within the left cerebellar hemisphere. Is is composed of mixed solid and cystic components and is surrounded by a mantle of tumour oedema.
The solid component demonstrates restricted diffusion on DWI. Following administration of contrast, vivid enhancement of the solid component is present.