cns tumors

1. DR PRAVEEN K TRIPATHI
25 July 2016 1

2. Sella/suprasellar:
• Optic
pathway/hypothalami
c glioma
• Craniopharyngioma
• Pitutary tumors
• Germ cell tumours
Pineal region:
• Germ cell tumours
• Pinealblastoma
(associated with
retinoblastoma)
• Astrocytoma
• Ganglioglioma
• Epidermoid
Intraventricular:
• Ependymoma
• Choroid plexus
papilloma/carcinoma
• Subependymal giant
cell astrocytoma
(associated with
tuberous sclerosis )
• Lesions arising from
suprasellar region
may involve 3rd
ventricle
• Colloid cyst (3rd
ventricle, usually
young adults)
25 July 2016 2

3. Schwannoma Meningioma Arachnoid cyst
Epidermoid Paraganglioma Metastasis
25 July 2016 3

4. Chordoma
Chondrosarco
ma
Esthesioneuro
blastoma
Sinonasal
carcinoma
Myeloma
25 July 2016 4

5. 25 July 2016 5

6. 25 July 2016 6

7. 25 July 2016 7

8. 25 July 2016 8

9. Best diagnostic clue
 CT Finding: Partially Ca++, partially solid, cystic suprasellar mass in a child
 MR Finding: High signal intensity suprasellar mass on pre-contrast Tl WI
CT
 cysts
 near CSF density
 typically large and a dominant feature
 present 90 % of the time
 solid component
 soft tissue density
 enhancement in 90%
 calcification
 seen in 90%
 typically stippled and often peripheral in location
MRI
 cysts: variable but ~80% are mostly or partly T2 hyperintense
 T1: iso- to hyperintense to brain (due to high protein content machinery oil cysts)
 solid component
 T1 C+ (Gd): vivid enhancement
 T2: variable or mixed
 calcification
 difficult to appreciate on conventional imaging
 susceptible sequences may better demonstrate calcification
 MR angiography: may show displacement of the A1 segment of the anterior cerebral artery (ACA)
25 July 2016 9

10. Unenhanced CT shows the calcifications more clearly.
After intravenous contrast the total extent of the lesion and its cystic
components are much evident.
25 July 2016 10

11.  unenhanced and enhanced
T1weighted sagittal images, a
compressed pituitary gland can be
identified.
There is a large intrasellar and
suprasellar mass with cystic and
enhancing components as well as
calcifications.
These findings in a child are
virtually pathognomonic for
craniopharyngioma
25 July 2016 11

12. Axial MRI T1-image showing
cystic craniopharyngioma
25 July 2016 12

13. Axial MRI T1 gadolinium
image showing sphenoidal
craniopharyngioma
25 July 2016 13

14. Rathke cleft cyst (RCC)
 Noncalcified, usually doesn't enhance, less heterogeneous, no solid components
 Small RCC may be indistinguishable from the rare intra sellar CP
 RCCs express cytokeratin 8,20 (CPs generally don't)
Suprasellar arachnoid cyst
 No Ca++, enhancement
Hypothalamic/chiasmatic astrocytoma
 Solid, or with small cystic/necrotic components
 Ca++ rarei robust enhancement common
Pituitary adenoma
 Rare in prepubescent children
 Isointense with brain, enhances strongly
 When cystic and hemorrhagic can mimic CP (Epi)dermoid tumors
 Minimal/no enhancement
25 July 2016 14

15. Imaging:
 Pituitary macroadenomas are by definition
>10 mm mass arising from the pituitary
gland, and usually extending superiorly.
Indentation at the diaphragma sellae can give
a snowman or figure eight configuration .
 Plain x-ray may show an enlarged sella
turcica;
CT
 No contrast attenuation can vary depending
on haemorrhagic, cystic and necrotic
components.
 Adenomas which are solid, without
haemorrhage, typically have attenuation
similar to brain (30-40 HU) and demonstrates
moderate contrast enhancement; less marked
than one typically sees in
meningiomas. Calcification is rare.
25 July 2016 15

16. MRI
 MRI is the preferred imaging modality
 Exquisitely delineate the mass & clearly visualise the optic chiasm, anterior cerebral
vessels and cavernous sinuses.
 Overall signal characteristics can significantly vary depending on tumour components
such as haemorrhage, cystic transformation or necrosis.
 T1
 typically isointense to grey matter
 larger lesions are often heterogeneous and vary in signal due to areas of cystic
change/necrosis/haemorrhage
 T1 C+ (Gd)
 solid components demonstrates moderate to bright enhancement
 T2
 typically isointense to grey matter
 larger lesions are often heterogeneous and vary in signal due to areas of cystic
change/necrosis/haemorrhage
 T2* gradient echo
 most sensitive for detecting any haemorrhagic components, which appear as areas of
signal loss
 calcification is rare, but should be excluded by reviewing CT scans
25 July 2016 16

17. PITUTARY MACROADENOMA
Pituitary macroadenoma there is suprasellar extension with elevation and compression
of the optic chiasm.
To distinguish between a pituitary macroadenoma and a meningioma.
1. Because they are soft tumors, they usually indent at the diaphragma sellae, giving
them a 'snowman' configuration
2. Enlargement of the sella turcica this generally only occurs with pituitary
macroadenomas that originate in the sella.
25 July 2016 17

18. The lesion starts in the
sella, which is enlarged,
and extends into the
suprasellar cistern.
Note the classic
'snowman' configuration
caused by constriction by
the diaphragma sellae.
The bloodfluid level,
indicating hemorrhage.
PITUITARY ADENOMAS
25 July 2016 18

19. Coronal T1 c+ MR shows a
macroadenoma that enhances strongly,
invades the left cavernous sinus, and
erodes the sellar floor. An area of
lesser enhancement may represent
cystic degeneration (arrow).
Coronal NECT shows
eroded sella caused by the
adenoma
25 July 2016 19

20.  On the T2weighted images
 The leaflets are displaced upwards by
tmacroadenoma which started in the
sella and is growing upwards.
 A lesion originating above the sella and
growing downwards would push the
leaflets in the other direction (this can
be seen with meningiomas ).
Sometimes a meningioma can
give a similar appearance.
Note there is no diaphragmatic
constriction and there is
uniform enhancement after
the administration of
intravenous gadolinium
which is typical of
meningioma.
25 July 2016 20

21.  Another common pathway of extension is laterally into the cavernous
sinus. Look for
1. If there more than 50% encirclement of the carotid artery? Note:
meningiomas tend to constrict the carotid artery, macroadenomas do
not.
2. Is there lateral displacement of the lateral wall of the cavernous sinus
compared to the opposite side?
3. Is there an increased amount of tissue interposed between the carotid
artery and the lateral wall of the cavernous sinus?
25 July 2016 21

22. Pitutary
macroadenoma
27 Yr male
h/o progressive loss of vision
rt > lt eye- 1month
Headache 1month
No signs symptom of
hormonal impalance
Bitemporal hemianopia
PRL 5.5 ng/dl
Ncct–hyperdense lesion in sella
CECT brain – hetergenously
enhancing lesion in sellar
region with scalloping of
adjacent bone
25 July 2016 22

23. Lobulated mass in sellar
and supra sellar region
Isointense on T1W &
T2W
Superior displacement of
optic chiasma
PITUITARY
MACROADENOMAS
25 July 2016 23

24. PITUTARY MACROADENOMA
Lobulated mass in sellar
and supra sellar region
Superior displacement of
optic chiasma
Moderate homogenous
enhancement with internal
hemorrhage
No extension in
cavernous sinus
25 July 2016 24

25. Classification of pineal tumors
Tumors of pineal parenchymal cells
(pinealomas) (about 25%)
• Pineoblastomas
• Pineocytomas
(ganglioglioma)
Germ cell tumors
• Germinomas (about 70%)
• Embryonal carcinoma (yolk sactumor)
• Endodermal sinus tumors
• Choriocarcinomas
• Teratomas (immature and mature)
Tumors of glial cell origin
• Astrocytoma
• Glioblastoma
Miscellanous tumors and cysts
25 July 2016 25

26. Imaging protocol
 The pineal region is best imaged with MRI although CT, angiography and ultrasound (in
infants) also play a role.
 A typical protocol would include:
 sagittal T1 and T2 (high resolution)
 pre and post contrast T1 axial and coronal
 FLAIR
 DWI
 SWI/gradient echo (to assess for presence of calcification)
Normal appearance
 The pineal gland is a small (~7 mm AP diameter) structure located at the posterior-most
aspect of the third ventricle
Calcification
 No calcification before the age of 5 years of age.
 Calcification larger than 1 cm in any one diameter, or any calcification before the age of 4
years considered pathological.
 Pineal parenchymal tumours (e.g. pineocytoma or pineoblastoma) tend to peripherally
disperse calcification where as germ cell tumours tend to engulf the calcifications. An easy
way to remember this is that pineoblastomas tend to blast the calcifications appart.25 July 2016 26

27. Solid component
 Cystic lesion, identification of a significant nodular component or of a thickened
(>2 mm) wall makes a pineal cyst unlikely and essentially excludes an arachnoid
cyst of cavum velum interpositum.
 DWI is also helpful as densely cellular tumours
(e.g.pineoblastoma, meningioma and lymphoma) tend to demonstrate increased
restricted diffusion compared to normal brain parenchyma.
Local invasion
 well circumscribed mass - pineal cyst, pineocytoma whereas more aggressive
masses can extend extensively into the adjacent brain and brainstem
e.g. pineoblastoma, some germ cell tumours.
CSF seeding
 Some aggressive pineal region masses tend to seed the ventricular and
subarachnoid space (e.g.pineoblastoma).
 Germinomas- multifocal disease involving not only the pineal gland but also the
floor of the third ventricle is relatively common
25 July 2016 27

28.  Facts:
 Germ Cell Tumors
 Causes Parinaud’s Syndrome
 disorder characterized by fixed upward gaze
 Location:
 Commonly in Pineal Region (>50%)
 Overlies tectum of midbrain
 Presentation:
 Obstructive Hydrocephalus due to aqueductal
stenosis
 On Imaging:
 CT
 Isodense or hyperdense
 Enhances with contrast
 MRI
 Isointense or Hypointense on T1-weighted
images
& enhance with gadolinium
 Hyperintense on T2 images
T1 Images
25 July 2016 28

29. MRI of an asymptomatic pineal cyst in a 17-year-old girl
25 July 2016 29

30. MRI gadolinium images
of:
(A) Pineoblastoma,
(B) Pineal epidermoid,
(C) Pineal meningioma,
(D) Tectal glioma,
(E) oligodendroglioma
25 July 2016 30

31. Ependymoma
Subependymoma
Choroid plexus papilloma
Colloid cyst
Central neurocytoma
Meningioma
Gaint cell astrocytoma
25 July 2016 31

32. General Features
 Best diagnostic clue-Heterogeneous signal, Soft or "plastic"
tumor: Squeezes out through 4th ventricle foramina into
cisterns.Indistinct interface with floor of 4th ventricle.
Radiographic Findings
 Myelography: May be helpful in showing "drop"metastases
CT Findings
 Infratentorial- 4th ventricle tumor, extends into CPA/cisterna
magna.Ca++ common (50%); +/- cysts, hemorrhage.
Hydrocephalus common.
 Supratentorial-Large heterogeneous periventricular mass. Ca++
common (50%).Variable heterogeneous enhancement.
25 July 2016 32

33. MR Findings
 T1WI-Heterogeneous, usually iso- to hypointense. Cystic foci
slightly hyperintense to CSF.
 T2WI-Heterogeneous, usually iso-to hyperintense
Hyperintense cystic foci, Hypointense Ca++, blood products
 T1C+: Mild to moderate, heterogeneous enhancement.
Axial NECT shows irregularly shaped 4th ventricular tumor with Ca++ and cyst
(open arrow) extending laterally into right CPA (curved arrow). Classic
ependymoma extending from 4th V into CPA cistern.25 July 2016 33

34. On MRI, heterogeneous secondary to necrosis,
hemorrhage and calcification.
Heterogenous contrast enhancement
Plasticity
Extension to the cerebellopontine angle is
characteristic of ependymomas
25 July 2016 34

35. Sagittal graphic shows posterior
fossa ependymoma extending out
through 4th ventricle foramen.
Axial T1 C+ MR shows lobular enhancing
mass extending out 4th ventricle through
foramen of Luschka into left
cerebellopontine angle, classic cellular
ependymoma
25 July 2016 35

36. MRI gadolinium (A) sagittal, (B) axial images showing fourth ventricular ependymoma
25 July 2016 36

37.  Rare, benign well-differentiated intraventricular ependymal
tumor
Presentation
 Most asymptomatic. 40% become symptomatic
 symptoms: Related to increased intracranial pressure,
hydrocephalus,Headache, gait ataxia, visual disturbance,
cranial neuropathy, nystagmus, vertigo, nausea, vomiting.
Age
 Middle-aged/elderly adult, (typically 5th-6th decades)
 Asymptomatic patients: Mean age = 60 years
 Symptomatic patients: Mean age = 40 years
Location
 Inferior fourth ventricle, frontal horns of lateral ventricle.
25 July 2016 37

38. General Features
 Best diagnostic clue: T2 hyperintense lobular,nonenhancing
intraventricular mass.
CT Findings
 Iso to hypodense intraventricular mass.Cysts or Ca++ may be
seen in larger lesions.Rarely hemorrhage
 No enhancement, mild enhancement (heterogenous)typical.
MR Findings
 TlWI-Intraventricular mass, hypointense or isointense.
 Typically homogeneous solid mass.
 T2WI-Hyperintense intraventricular mass
 Heterogeneity related to cystic changes, blood products or Ca++
may be seen in larger lesions
 No edema seen in adjacent brain parenchyma
25 July 2016 38

39. Sagittal graphic shows a solid, well-
circumscribed mass arising from the floor
of the 4th ventricle with mild mass effect
(arrow). Note lack of hydrocephalus,
typical of subependymoma.
Sagittal T2WI MR shows a solid
hyperintense mass along the inferior 4th
ventricle (arrow). 43 year old male with
headaches and trigeminal neuralgia.
25 July 2016 39

40. Axial NECT shows a calcified 4th
ventricular mass in this 52 year old
female. Calcification is more
commonly seen in 4th Ventricular
subependymomas.
Sagittal T1 C+ M R shows a classic
nonenhancing 4th ventricular
subependymoma (arrow). 4th
ventricular floor origin is typical.
25 July 2016 40

41. On Imaging:
 CT:
 Smooth, round lesions
lesion hyperdense to brain
tissue
 Thin rim of enhancement
after IV contrast
 MRI:
 T1-weighted hyperintense
lesion due to proteinaceous
nature.
 T2-weighted shows
hypointense lesion
25 July 2016 41

42.  Ant 3rd ventricle
 Neuroepithelial
cyst
 Hypo to hyperI
on T1 & T2WI
25 July 2016 42

43. General Features
 Best diagnostic clue: Child with strongly enhancing, lobulated
intraventricular mass.
Radiographic Findings
 Increased cranial-to-facial ratio
 Sutural diastasis due to hydrocephalus
CT Findings
 Intraventricular bosselated mass
 75% iso- or hyperattenuating. Ca++ in 25%, hydrocephalus
 Intense, homogeneous enhancement
 Heterogeneous enhancement suggests choroid plexus carcinoma
(CPCA).
25 July 2016 43

44. MR Findings
 TlWI-Well delineated, lobulated mass. Iso- to hypointense
 CSF trapped between papillae :-a mottled appearance
 T2WI-Iso- to hyperintense. ± Internal linear and branching
vascular flow voids. Hydrocephalus
 Foci of diminished signal representing Ca++
 ± Intratumoral hemorrhage.
 T1 C+ :Robust homogeneous enhancement.
Ultrasonographic Findings
 Hyperechoic mass with frond-like projections
 Mass echogenicity similar to normal choroid plexus
 Hydrocephalus
 Color Doppler: Hypervascular mass with bidirectional flow.
25 July 2016 44

45. Axial CECT shows a vividly enhancing
lobulated CPP arising from the trigone of
left lateral ventricle. Note normal
contralateral choroid plexus (arrow),
"overproduction" hydrocephalus.
Axial CECT shows an obstructing, robustly
enhancing choroid plexus papilloma
arising from roof of third ventricle. Note
papillary surface projections
25 July 2016 45

46. Axial PD/Intermediate MR shows an
expansile intraventricular choroid
plexus papilloma with internal flow
voids (arrow).
Sagittal T1C+ MR shows an
enhancing mass with lobulated
margins (arrow), obstructing fourth
ventricular outlets.
25 July 2016 46

47. 25 July 2016 47

48. Neurocytoma
Magnetic resonance
image of central
neurocytoma. FLAIR
(A) and postcontrast T1-
weighted (B) axial
images of a central
neurocytoma projecting
from the septum
pellucidum into the
anterior body of the left
lateral ventricle.
25 July 2016 48

49. tumor location T2WI contrast
Central
neurocytoma
Lat, septum
pellucidum
Iso to GM dense
ependymoma lateral Heterogeneous heterogeneous
meningioma lateral Iso to GM dense
Choroid
plexus tumor
fourth heterogeneous dense
Colloid cyst third Hyper to GM none
25 July 2016 49

50. Cerebellar
liponeuroc
ytoma
Metastasis
16%
Hemangiobl
astoma 7-
12%
Pilocytic
astrocytoma
(2nd
decade)
Brain stem
glioma (1%
of adult
tumor)
Choroid
plexus
tumor
(<1%)
25 July 2016 50

51. Axial CT contrast image showing
multiple metastases
Axial T2 image showing SINGLE
metastases
25 July 2016 51

52. General Features
 Best diagnostic clue-Cystic cerebellar mass with enhancing
mural nodule
 Enlarged optic nerve/chiasm/tract with variable enhancement.
CT Findings
 Discrete cystic/solid mass. May have little or no surrounding
edema. Solid component hypo- to isodense.
 Ca++ 20%, hemorrhage rare
 Often cause obstructive hydrocephalus.
 > 95% enhance (patterns vary).50% non enhancing cyst.
strongly enhancing mural nodule. 40% solid with necrotic
center, heterogeneous enhancement
25 July 2016 52

53. MR Findings
 T1WI- Solid portions iso/hypointense to GM. Cyst
contents iso- to slightly hyperintense to CSF
 T2WI-Solid portions hyperintense to GM. Cyst
contents hyperintense to CSF.
 T1 C+: Intense but heterogeneous enhancement of
solid portion or mural nodule. Cyst wall occasionally
enhances.
Ultrasonographic Findings
 Real Time-Solid components are hyperechoic relative
to brain parenchyma. Cysts may contain debris.
25 July 2016 53

54. 25 July 2016 54

55. •A large partially cystic mass in the right cerebellar hemisphere.
•The solid component only minimally enhances with a focal region demonstrating
more prominent ring enhancement.
•The fourth ventricle is effaced, and the lateral ventricles are enlarged.
•There is also marked effect on the brainstem with the prepontine and
perimesencephalic cisterns obliterated.25 July 2016 55

56. Axial T2W and T1C+ scans
25 July 2016 56

57. (A)MRI T1,
(B) MRI gadolinium
images showing
sellar pilocytic
astrocytoma,
(C) MRI T1,
(D) MRI gadolinium
images showing
cerebellar
pilocytic
astrocytoma
25 July 2016 57

58. CT
 The mural nodule is isodense to brain on non-contrast scans with fluid density surrounding cyst
 Bright enhancement of the nodule is demonstrated with contrast
 The cyst walls do not usually enhance & calcification is not a feature
MRI T1
 Hypointense to isointense mural nodule,
 CSF signal cyst content
 T1 C+ (Gd)
 mural nodule vividly enhances BUT cyst wall does not enhance
T2
 Hyperintense mural nodule
 Flow voids due to enlarged vessels may be evident especially at the periphery of the cyst, seen in 60-
70% of cases
 Fluid filled cyst, similar to CSF
MR perfusion imaging: high rCBV ratios
Angiography (DSA)
 Enlarged feeding arteries and often dilated draining veins are demonstrated, with a dense tumour
blush centrally
25 July 2016 58

59. Coronal MRI gadolinium image showing
cystic hemangioblastoma with a mural
nodule
CT showing cystic hemangioblastoma
with a mural nodule
25 July 2016 59

60. Sagittal MRI gadolinium image showing a
cerebellar and spinal hemangioblastomas
Computed tomography angio showing
vascularity of left cerebellar
hemangioblastoma25 July 2016 60

61. CT
• mass arising from the vermis, resulting in effacement of the fourth ventricle / basal
cisterns and obstructive hydrocephalus.
•Usually hyperdense (90%) and cysts formation/necrosis is common (40-50%)
•Calcification is seen in 10-20% of cases .
•Enhancement is present in over 90% of cases and is usually prominent
MRI
T1
hypointense to grey matter
T1 C+ (Gd)
overall 90% enhance, often heterogeneously
T2/FLAIR
overall are iso to hyperintense to grey matter
heterogeneous due to calcification, necrosis and cyst formation
surrounding oedema is common
DWI/ADC- restricted diffusion (low ADC values)
MR spectroscopy
elevated choline
decreased NAA
may show a taurine peak
61
Medulloblastoma
25 July 2016

62. 25 July 2016 62

63. (A) Contrast CT, (B) MRI T1, (C) MRI gadolinium images showing medulloblastoma
25 July 2016 63

64. • Imaging
– MRI is the method of
choice to image these
tumors (brainstem
glioma appears isodense
on CR and can be
missed);
– Appear isointense or
hypointense on T1
images, hyperintense on
T2, and inhance
uniformly and brightly
with IV contrast;
25 July 2016 64

65. 25 July 2016 65
Magnetic resonance imaging axial sections showing: (A) “Diffuse infiltrating
type” as compared to. (B) “Expanding type” of brainstem glioma.

66. Schwannoma Meningioma Arachnoid cyst
Epidermoid Paraganglioma Metastasis
25 July 2016 66

67. CT
 May show erosion and widening of the internal acoustic
canal.
 The density of these tumours on non-contrast imaging is
variable, and often they are hard to see, especially on
account of beam hardening and streak artefact form the
adjacent petrous temporal bone.
 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
 may have associated peritumoural arachnoid cysts
 T1 C+ (Gd)
 contrast enhancement is vivid
 but heterogeneous in larger tumours
25 July 2016 67

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74. 25 July 2016 74

75.  Epidermoid. A, Contrast-enhanced axial
T1-weighted image demonstrates right
cerebellopontine angle mass (arrow),
showing close to cerebrospinal fluid
(CSF) intensity signal on this sequence,
and no postcontrast enhancement.
 B, Fluid-attenuated inversion recovery
(FLAIR) image, showing the same lesion
demonstrating signal intensity somewhat
higher than CSF.
 C, On diffusion-weighted image, the
lesion is hyperintense, whereas on the
apparent diffusion coefficient map
calculated from the diffusion data
 (D), the lesion (short arrow) is
significantly lower in intensity than is the
CSF in the fourth ventricle (long arrow).
25 July 2016 75

76. meningioma
• usually more
homogeneous in
appearance:
significant signal
heterogeneity with
cystic or
haemorrhagic areas
is more typical of
vestibular
schwannoma than
meningiomas
(although cystic
meningiomas do
occur)
• meningiomas tend to
have a broad dural
base
• usually lack trumpet
IAM sign
• calcification more
common
epidermoid
• no enhancing
component
• very high signal on
DWI
• does not widen the
IAC
metastasis
• uncommon
• usually does not
remodel the IAC as
metastases are
usually present for
only a short time
ependymoma
• centered on the
fourth ventricle
• does not extend into
the IAC
• usually younger
patients
Differential diagnosis
The most frequent differential to be considered are:
25 July 2016 76

77. Chordoma
Chondrosarco
ma
Esthesioneuro
blastoma
Sinonasal
carcinoma
Myeloma
25 July 2016 77

78. (A) Lateral radiograph; (B) Coronal MRI; (C) CT bone window images showing a
giant osteoma of anterior skull base
25 July 2016 78

79. 25 July 2016 79
 On CT image- isointense on the non-contrast studies. There is irregular bone
destruction at its site of origin, which may be in the midline of the clivus or
eccentrically located.
 The tumour may also show areas of calcification.
MRI
 Lobulated masses arising from the clivus. They manifest low signal intensity
on T1-weighted images and have high signal intensity on T2-weighted images.
 They do enhance with the administration of gadolinium, but this occurs to a
variable degree.
 They can vary greatly in size and distribution.
 They often extend intracranially as well as extracranially into adjacent
anatomical areas
 Differentiating chordomas from chondrosarcomas is often difficult due to the
identical imaging appearance.
 Chondrosarcomas usually arise eccentrically at the petroclival synchondrosis.

80. 25 July 2016 80
MRI scan of 43-year-old man showing a enhancing large clival
chordoma at the skull base

81. 25 July 2016 81

82. Age distribution
Tumor spread
• Intra- versus
Extraaxial
• Midline crossing
• Multifocal disease
• Cortical based tumors
CT and MR
Characteristics
• Fat - Calcification -
Cyst - High density
• High on T1
• Low on T2
• Diffusion weighted
imaging
• Perfusion Imaging
Enhancement
Differential
diagnosis for
specific
anatomic area
• Skull base
• Sella/suprasellar
• Cerebello-pontine
angle
• Pineal region
• Intraventricular
• 4th ventricle
Tumor Mimics
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Thank you