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SpineIntraspinal Masses
Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology Department , Zagazig University Hospitals
EgyptFINR (Fellowship of Interventional
Neuroradiology)[email protected]
Knowing as much as possible about your enemy precedes successful battle
and learning about the disease process precedes successful management
Intraspinal Masses1-Osseous Lesions2-Epidural (Extradural) Masses3-Subdural (Intradural) Masses4-Intramedullary Masses5-Cauda Equina & Filum Terminale Masses6-Spinal Metastases
(A) Intradural , Intramedullary , (B) Intradural , Extramedullary , (C) Extradural
1-Osseous Lesions : See Bone Tumorsa) Benign :1-Enostosis2-Osteoid Osteoma3-Osteoblatoma4-ABC5-Osteochondroma6-Hemangioma
b) Malignant :1-Chordoma2-Chondrosarcoma3-Osteosarcoma4-Ewing Sarcoma & PNET5-Multiple Myeloma6-Lymphoma7-Metastases
2-Epidural (Extradural) Masses :1-Prolapsed or Sequestrated intervertebral disc 2-Metastases3-Epidural Hematoma4-Epidural Abscess5-Epidural Angiolipoma6-Epidural Lipomatosis7-Epidural Arachnoid , Epidermoid & Dermoid
Cysts
1-Prolapsed or Sequestrated intervertebral disc :
-See Degenerative Diseases of the Spine
Migration & Sequestration
2-Metastases :-See Spinal Metastases
3-Epidural Hematoma :a) Etiologyb) Radiographic Features
a) Etiology :-May be due to trauma , dural AVM &
anticoagulant therapy-May occur spontaneous
b) Radiographic Features :-Most epidural hematomas extend over
several vertebral segments which show signal characteristics of blood
(a) T1 and (b) T2 showing extradural hematoma from L4-S2 ventrally
(A) T1 shows epidural masses at T10 to L2 level that have homogeneous intermediated signal intensity representing acute hematoma (arrow) , (B) T2 show epidural masses at T10 to L2 level that have hyperintense with hypointense foci (arrow) , (C) T2 show epidural mass that have hyperintense foci (yellow arrow) and displace thecal sac toward left side (arrow head)
Fluid collection , isointense in T1 (A, arrow) and T2 hypointense (B, arrow) in the epidural space within the spinal canal at the L2-L3 disk space causing narrowing of the canal
T1 revealing isointense linear biconvex mass compressing on the lower thoracic spinal cord and cauda equina (arrow heads) , (b) Same lesion showing heterogenous signal of hyperintensity (arrow heads) and hypointensity (arrow) on T2
Phase Time Hemoglobin , Location
T1 T2
1-Hyperacute <24 hrs Oxyhemoglobin, intracellular
Isointense or hypointense
Hyperintense
2-Acute 1-3 d Deoxyhemoglobin, intracellular
Hypointense Hypointense
3-Early subacute
>3 d Methemoglobin, intracellular
Hyperintense Hypointense
4-Late subacute
>7 d Methemoglobin, extracellular
Hyperintense Hyperintense
5-Chronic >14 d Ferritin and hemosiderin, extracellular
Hypointense Hypointense
4-Epidural Abscess :-See Spinal Infection & Inflammation
T1+C
T1+C Fat saturation
5-Epidural Angiolipoma :a) Incidenceb) Radiographic Features
a) Incidence :-Rare-More frequently encountered in women and typically in
middle age (40-50 years of age) -Can be divided into infiltrating and non-infiltrating varieties
and both as seen in the epidural space :1-Non-infiltrating angiolipomas :*Are more common and are usually located in the dorsal
epidural space , typically in the thoracic region2-Infiltrating angiolipomas :*Are more common in the anterior epidural space and can
infiltrate not only adjacent soft tissues but also adjacent verterbrae
b) Radiographic Features :MRI :*T1 :-Isointense to hyperintense-High signal fatty component-Intermediate signal vascular component*T2 :-High signal-Flow voids are usually absent but enlarged vessels in the region
may be visible*T1+C :-Vivid enhancement of non-fatty components
(a) T1 showing hypointense epidural lesion at D4-5 level compressing the spinal cord , (b) T2 showing hyperintense epidural lesion , (c) T2 demonstrating severe cord compression
(a) T1 showing a hypointense dorsally located extradural mass causing thecal sac compression (b) T2 showing the lesion hyperintense with obliteration of CSF spaces
(a) T1 showing a homogeneous hyperintense mass compressing the spinal cord (b) T2 showed that mass was also hyperintense (c) T1+C showed obvious enhancement of the mass
Infiltrating angiolipoma , (a) T1 shows extradural mass located in posterior epidural space at level of T3 extending to T5 (arrows) , mass displays inhomogeneous predominately low signal intensity mixed with intermediate signal intensity content (b) T1+C shows marked enhancement of mass (c) T1+C with fat saturation shows well delineated extent of enhancing tumor along neural foramen bilaterally more prominent on right side (d) T1+C with fat saturation shows involvement of tumor in right demifacet region of T4 vertebra (arrows)
6-Epidural Lipomatosis :a) Incidenceb) Radiographic Features
a) Incidence :-Refers to excessive accumulation of fat within the spinal
epidural space such that the thecal sac is compressed-Causes :1-Obesity2-Cushing disease3-Cushing syndrome : most frequently due to corticosteroid
use4-Prolactinoma5-May be idiopathic-Typically involves the lower lumbar and/or lower thoracic
levels
b) Radiographic Features :MRI :-There is a often generalized excess of fat seen in the
extradural space , as a result the dural sac can appear narrowed or even resemble a "Y" shaped configuration
*T1 :-High signal*T1 Fat suppression :-Shows fat suppression*T2 :-High signal
T1 T2
Spinal epidural lipomatosis , the thecal sac has the typical "Y" configuration on axial section at the L5 level
7-Epidural Arachnoid , Epidermoid & Dermoid Cysts :
-See later
3-Subdural (Intradural, Extramedullary) Masses:
1-Spinal Nerve Sheath Tumors2-Meningioma3-Leptomeningeal Metastases4-Spinal Arachnoid Cyst 5-Spinal Epidermoid Cyst6-Spinal Dermoid Cyst7-Spinal Neuroenteric Cyst8-Intradural Spinal Lipoma
1-Spinal Nerve Sheath Tumors :a) incidenceb) Radiographic Features
a) Incidence :-The most common intradural extramedullary mass-They include , in order of decreasing frequency :1-Schwannoma2-Neurofibroma3-Ganglioneuroma-35-45% of patients with nerve root tumors have
NF2 , multiple lesions are common in these patients , neurofibromas are associated with NF1 , whereas schwannomas are associated with NF2
b) Radiographic Features : 1-CT2-MRI
1-CT :-Density varies from hypodense to slightly
hyperdense-Widened neural exit foramina-Bone erosion-Vertebral body scalloping-Paraspinous soft tissue mass : (dumbbell
and extradural lesions)
2-MRI :-Schwannoma and neurofibroma are often indistinguishable
radiographically-In general , appear as rounded lesions often with
associated adjacent bony remodelling , when large they may either align themselves with the long axis of the cord forming sausage shaped masses which can extend over several levels or may protrude out of the neural exit foramen forming a dumb-bell shaped mass
-Although neurofibromas and schwannomas can look identical , schwannomas are frequently associated with hemorrhage , intrinsic vascular changes (thrombosis ; sinusoidal dilatation) , cyst formation and fatty degeneration , these findings are rare in neurofibroma
-Neurofibromas tend to encase the nerve roots , in contrast to schwannomas which commonly displace the nerve root due to their asymmetric growth
-Schwannomas are usually round , whereas neurofibromas are more commonly fusiform
A dumbbell shaped tumor is outlined as it begins on a spinal root and extends both out of and into the spinal canal (C)
Dumbbell-shaped schwannoma (black arrow)
*T1 :-75% are isointense , 25% are hypointense*T2 :-More than 95% are hyperintense , often with
mixed signal *T1+C :-Virtually 100% enhance-Neurofibroma : uniform enhancement-Schwannoma : show peripheral enhancement
T1
T2
T1+C
T1+C
T1+C
Multiple schwannomas consisting with NF2
T1+C shows bilateral neurofibromas consistent with NF1
2-Meningioma :a) Incidenceb) Location c) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-Meningiomas arising from the coverings of the
spinal cord represent a minority of all meningiomas (approximately 12%) but are the second most common intradural extramedullary spinal tumor representing 25% of all such tumors
-Peak incidence is in the fifth and sixth decades-Females are approximately ten times more
commonly affected than males-There is an increased incidence of spinal
meningiomas in patients with neurofibromatosis type 2 and in fact in the pediatric population , meningiomas uncommonly occur outside of the setting of NF2
b) Location :-Cervical spine : 15%-Thoracic spine : 80%-Lumbosacral spine : uncommon-Meningiomas are often located posterolaterally in
the thoracic region and anteriorly in the cervical region
-Most meningiomas are solitary lesions (98%) , multiple meningiomas are most often associated with NF2
c) Radiographic Features : MRI-Well-circumscribed-Broad-based dural attachment-Dural tail sign (occurs as a result of thickening of
the dura)*T1 :-Isointense to slightly hypointense-May have a heterogenous texture*T2 :-Isointense to slightly hyperintense*T1+C :-Moderate homogeneous enhancement *N.B. :-Occasionally , densely calcified meningiomas are
hypointense on T1 and T2 and show only minimal contrast enhancement
Dural tail (arrows)
T1
T2
T1+C
T1+C
d) Differential Diagnosis :Meningioma Neurogenic Tumors
Commonly thoracic Any level
Mainly in middle-aged female
M=F
Occasional calcification No calcification
Dural tail , homogenous enhancement
Heterogenous enhancement
No foraminal extension Foraminal extension (dumbbell shape)
3-Leptomeningeal Metastases :-In the pediatric population , the most
common intradural extramedullary neoplasms are leptomeningeal metastases resulting from primary brain tumors
-See Spinal Metastases
4-Spinal Arachnoid Cyst :a) Incidenceb) Locationc) Radiographic Features d) Differential Diagnosis
a) Incidence :-Uncommon-Spinal arachnoid cysts are CSF filled sacs
contained by arachnoid mater -Spinal arachnoid cysts may present at any age ,
there is no gender predilection-They may be congenital or acquired , secondary
arachnoid cysts are usually due to trauma , hemorrhage , inflammation , surgery or lumbar puncture
b) Location :-Most primary intradural spinal arachnoid cysts are
dorsal to the cord , they occur at the following locations :
1-Thoracic : 80%2-Cervical : 15%3-Lumbar : 5%-May be either intra-dural (type III meningeal cyst)
or extra-dural (type Ia meningeal cyst)
*N.B. :-Spinal meningeal cysts can be classified into :*Type I : extradural meningeal cyst without neural
tissueType Ia : extradural spinal arachnoid cystType Ib : sacral meningocoele*Type II : extradural meningeal
cyst containing neural tissue , e.g. Tarlov cyst*Type III: intradural spinal arachnoid cyst
Ia Ib II III
c) Radiographic Features : MRI-As the cysts follow the intensity of CSF and their walls are
generally not visible , they may not be identified unless the cord is displaced
*T1 :-CSF intensity *T2 :-CSF intensity , may even be brighter than CSF on account
of no signal loss from pulsation/flow *T1+C :-No contrast enhancement *Diffusion :-No evidence of restricted diffusion
T1 T2
T1 T2
T1 T2 T1+C
Epidural Arachnoid Cyst , (A,B) T1 & (C,D) T2
T2 shows epidural arachnoid cyst
Epidural arachnoid cyst , (A) T1 & (B,C) T2
d) Differential Diagnosis :-From Spinal Epidermoid Cyst , Spinal Dermoid Cyst &
Spinal Neuroenteric Cyst :*Spinal Epidermoid Cyst :-Bright on DWI-Hyperintense on FLAIR-Common with vertebral anomalies*Spinal Arachnoid Cyst :-No restriction on DWI-Signal suppression on FLAIR-Vertebral anomalies uncommon
*Spinal Dermoid Cyst :-Usually contains fatty elements-Less likely to demonstrate diffusion restriction on
DWI-Patients are usually younger than 20 years of age*Spinal Neuroenteric Cyst :-Thoracic and cervical regions most common-Usually ventral to spinal cord-Associated vertebral anomalies are common
5-Spinal Epidermoid Cyst :a) Incidenceb) Locationc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-Rare-Cystic tumors lined by squamous epithelium ,
unlike dermoid cysts , they do not contain skin appendages (hair follicles , sweat glands & sebaceous glands)
-They may be congenital (often do not present until the second to fourth decade of life) or acquired
-Commonly associated with spinal malformations such as spina bifida and hemivertebrae
b) Location :-They are usually extramedullary but rarely
can be intramedullary (Very rare)
c) Radiographic Features : MRI-Signal intensity may be homogeneous or
heterogeneous according to the variable water , lipid and protein composition of the cyst
*T1 :-Hypointense (similar to CSF) *T2 :-Hyperintense (similar to CSF)*FLAIR :-Hyperintense compared to CSF *T1+C :-No enhancement or a thin rim of capsular
enhancement *Diffusion :-Bright (with corresponding low intensity on ADC
map)
(A) T2 , (B) T1 & (C) T1+C
(A,B&C) Diffusion with b-value 0 , 250 & 1000 respectively showing tumor intensity remains high (arrow) , (C,D&E) ADC maps showing low intensity
d) Differential Diagnosis :-See Spinal Arachnoid Cyst
6-Spinal Dermoid Cyst :a) Incidenceb) Locationc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-Uncommon-Uni or multilocular cystic tumors lined by
squamous epithelium containing skin appendages (hair follicles , sweat glands & sebaceous glands)
-They are congenital in origin-They generally present in patients younger than
20 years-Males and females are affected equally
b) Location :-Forty percent are intramedullary and 60%
are extramedullary-Most often located in the lumbosacral
region (60%) and cauda equina (20%)
c) Radiographic Features : MRI-Signal intensity may be homogeneous or heterogeneous-If rupture occurs , multifocal T1 high signal areas (fat) are
demonstrated within the subarachnoid space and/or ventricular system
*T1 :-Hypointense : water content-Hyperintense : due to the presence of fatty secretions of
sebaceous glands*T2 :-Hyperintense*FLAIR :-Hyperintense compared to surrounding CSF *T1+C :-No enhancement or mild rim enhancement *Diffusion :-Less likely to show diffusion restriction than epidermoid
T1 T2 T1+C
Intramedullary dermoid cyst , (A) T1 shows hypointense intramedullary space occupying lesion , (B) T2 shows hyperintense lesion with "whorls“ , (C) T1+C shows peripheral ring enhancement and irregular enhancement within the lesion
d) Differential Diagnosis :-From Arachnoid Cyst , Epidermoid Cyst ,
Neuroenteric Cyst & Spinal Lipoma :See Spinal Arachnoid Cyst*Spinal lipoma :-Homogeneously hyperintense on T1 and T2
weighted images-Cervical and thoracic regions most common
7-Spinal Neuroenteric Cyst :-See Congenital Diseases of the Spine
MRI of an intradural/extramedullary neurenteric cyst located at the craniocervical junction , Coronal (a) and sagittal (b) T1 showing the ventrally located homogenous lesion compressing the cervical spinal cord , Axial imaging demonstrates cord flattening by the anteriorly located neurenteric cyst hyperintense on both T1 (c) and T2 (d)
8-Intradural Spinal Lipoma :a) Incidenceb) Locationc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-Intradural spinal lipomas typically present around the
second and third decades of life-Males and females are equally affected-Vertebral and dermal abnormalities are not a feature of
these lesions as they are with the more commonly seen lipomas associated with forms of dysraphism
-Mature fatty tissue within the spinal dura can be seen in a number of entities :
1-lipomyelomeningocele : 84%2-Lipoma of the filum terminale : 12%3-Intradural lipoma : 4%
b) Location :-Intradural lipomas may occur anywhere in the
spinal canal-In adults they are most commonly found in the
thoracic region , whereas in children the cervical spine appears to be the most common site
-They usually occur along the dorsal midline of the spinal cord , the spinal cord is flattened ventrally
c) Radiographic Features : MRI-Intradural spinal lipomas are sharply
circumscribed masses largely conforming to the dura but distorting the cord , they follow fat signal on all sequences
*T1 :-Hyperintense*T2 :-Hypointense*Fat Suppressed Sequences :-Hypointense*T1+C :-No enhancement
T1 T2 Fat Suppression STIR
T1 T2 T1+C (Fat sat.)
d) Differential Diagnosis :1-Lipomyelomeningocele :-Is a form of occult spinal dysraphism-Mass is often palpable-May have cutaneous stigmata2-Lipoma of the terminal filum :-Fatty infiltration of the filum terminale3-Dermoid cyst :-Mixed signal intensity-May be associated with a dermal sinus
LMM Lipoma of FT Dermoid
4-Intramedullary Masses :1-Ependymoma2-Astrocytoma3-Hemangioblastoma4-Lymphoma5-Metastases
1-Ependymoma :a) Incidenceb) Locationc) Radiographic Featuresd) Myxopapillary Ependymomae) Differential Diagnosis
a) Incidence :-The most common intramedullary neoplasm
in adults-They are the second most common
intramedullary neoplasm in the pediatric population
-Peak incidence is in the fourth decade-More in males-There is an increased incidence with NF2
b) Location :-Can occur anywhere along the spinal cord ,
however the cervical cord is the most common site (44%)
c) Radiographic Features : MRI-Widened spinal cord (as ependymomas
arise from ependymal cells lining the central canal , they tend to occupy the central portion of the spinal cord and cause symmetric cord expansion)
-Well circumscribed mass-Average length of four vertebral body
segments
*T1 : -Low to intermediate*T2 : -High with cap sign : extreme hypointensity
(hemosiderin) at its cranial or caudal margin (due to associated hemorrhage)
*T1+C : -Intense enhancement (homogenous)
T1
T1
T2
T2
T2 shows a heterogeneous mass located centrally , displacing normal cord laterally (white arrow heads) with associated peritumoural cysts/syrinx (white arrow) and prominent inferior hemosiderin capping (black arrow)
T1+C
T1+C
T1+C
(A) T2 & (B) T1+C show multiple ependymomas in NF2
d) Myxopapillary Ependymoma :1-Incidence2-Location3-Radiographic Features
1-Incidence :-Variant type of spinal ependymoma-They represent 13% of all spinal
ependymomas and are by far the most common tumors of the conus medullaris and filum terminale
-The mean age for presentation of this tumor is in the fourth decade
2-Location :-Occur exclusively in the conus medullaris
and filum terminale
3-Radiographic Features : MRI-Smaller tumors tend to displace the nerve
roots of the cauda equina , larger tumors often compress or encase them
-Sausage shaped , well-demarcated and/or encapsulated
-Prone to hemorrhage and can present with subarachnoid hemorrhage
*T1 :-Isointense-Prominent mucinous component
occasionally results in T1 hyperintensity*T2 :-As ependymoma*T1+C :-As ependymoma
T1 T2 T1+C
T1 T2 T1+C
T1 T2 T1+C
T1
T2
T1+C
e) Differential Diagnosis :
Ependymoma Astrocytoma Hemangioblastoma
1-Incidence 60 % of adults4th-5th decade
30 % of adults3rd-4th decade90 % of children
6 % of adults30-40 years , younger in VHL
2-Edema 60 % 25 % Extensive
3-Location Cervical , conus , filum terminale (MP)
Thoracic cord followed by cervical cord
Thoracic cord followed by cervical cord
Ependymoma Astrocytoma Hemangioblastoma
4-Location in the cord
Central Eccentric Superficial , peripheral , frequently posterior
5-Enhancement Homogeneous , mild to moderate
Heterogeneous , mild to moderate
Intense
6-Mean height 3-4 vertebrae 5-6 vertebrae 1 vertebra (occasionally large)
7-Cysts/Syrinx Commonly has satellite cysts or syrinxes
More commonly intratumoral cysts than satellite cysts
Syrinx in 50-100 %
8-Borders Well-defined Ill-defined Well-defined
Ependymoma Astrocytoma Hemangioblastoma9-MRI Signal T1 : Hypointense
(except MP which may be hyperintense)T2 : Hyperintense (mild)
T1 : Hypointense to isointenseT2 : Hyperintense (mild)
T1 : Hypointense to isointenseT2 : isointense to hyperintense
10-Distinguishing Features
Associated hemosiderin (cap sign) , hemosiderin on either end due to chronic hemorrhage
May be large & infiltrating
-Syrinx or edema-Up to 33 % associated with VHL-May be multiple in VHL-Associated flow voids or pial enhancement
2-Astrocytoma :a) Incidenceb) Locationc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-The second most common intramedullary tumors-They account for 60% of pediatric intramedullary
tumors , making them the most common spinal cord tumor in children
-The peak incidence is 3rd decade-There is an increased incidence
in neurofibromatosis type 1
b) Location :-The most common location of astrocytomas
is the thoracic cord followed by cervical cord
c) Radiographic Features : MRI-Cause diffuse cord expansion-As astrocytomas arise from cord parenchyma
(rather than the central canal as is the case for ependymomas) , they typically have an eccentric location within the spinal cord
-A poorly defined infiltrating mass (that is not mass-like)
-Typically long multisegment intramedullary masses that , the average length of involvement is 4-7 vertebral body segments
-Unlike ependymomas , hemorrhage is uncommon
*T1 : -Low to intermediate*T2 : -High*T1+C :-It usually enhances (heterogenous i.e.
patchy)
T1 T2 T1+C
T1
T2
T1+C
T1+C
T1+C
d) Differential Diagnosis :-See before
3-Hemangioblastoma :a) Incidenceb) Locationc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-The third most common intramedullary
spinal neoplasm-Peak presentation in the fourth decade-80 % of hemangioblastomas are solitary , if
multiple lesions are present , Von Hippel-Lindau syndrome should be suspected
b) Location :-The most common location is the thoracic
cord (50%) followed by the cervical cord (40%)
c) Radiographic Features : MRI-Although they usually appear as discrete
nodules , there can be diffuse cord expansion , an associated tumor cyst or syrinx is common (50-100%)
-A mass with round and well-defined margins-The cyst mural nodule appearance classically
seen in cerebellar hemangioblastomas may be seen with larger lesions
-Care should be taken to image the whole neuraxis to ensure that no other lesions are present
*T1 :-Small tumors : Isointense -Large tumors : Isointense or Hypointense*T2 :-Small tumors : High-Large tumors : Heterogenous with focal flow
voids*T1+C :-Small tumors : Intense enhancement-Large lesions : Heterogeneous enhancement
T1 T2 T1+C
(A) T2 shows a hyperintense lesion with spinal cord swelling from lower medulla to T2-3 level , (B) T1+C shows well enhancing mass
(A) T2 , (B) T1 & (C) T1+C show cyst mural nodule appearance
T1+C shows hemangioblastoma at L1-2 level (arrows) , another tumor is at T7-8 and an extensive leptomeningeal enhancement along the spinal cord
T1+C
T1+C shows enhancing nodule (arrow) with associated syrinx (*)
T1+C shows intramedullary homogeneously enhanced mass lesion associated with syrinx on MRI , (a) Cervical cord hemangioblastoma in a VHL patient , (b) Lumbar cord hemangioblastoma in a VHL patient
T1+C
d) Differential Diagnosis :-See before
4-Lymphoma :a) Incidenceb) Location c) Radiographic Features
a) Incidence :-Uncommon manifestation of lymphoma ,
although lymphoma more commonly involves the vertebral body (vertebral body tumors) or epidural compartment , intramedullary lymphoma may rarely occur
-Intramedullary spinal lymphoma accounts for 3.3% of all CNS lymphoma which constitutes only 1% of all lymphomas in the body
-More in immunocompromised
b) Location :-More in the cervical cord
c) Radiographic Features : MRI-The MRI appearance is nonspecific with respect
to other intramedullary neoplasms*T1 :-Isointense*T2 :-Hyperintense (this is in contrast to the
characteristic low T2 signal intensity that is seen in intracranial lesions)
*T1+C :-Heterogeneous
T1 T2 T1+C
(a) T1 sagittal , (b) T2 sagittal , (c) T1 axial , (d) T2 axial and (e) MR myelogram show sausage shaped intradural extramedullary lesion at L1 and L2 spinal levels
5-Metastases :-See Spinal Metastases
5-Cauda Equina & Filum Terminale Masses :
a) Myxopapillary Ependymomab) Spinal Nerve Sheath Tumorsc) Lipoma of the Filum Terminale
a) Myxopapillary Ependymoma :-See before
b) Spinal Nerve Sheath Tumors :-See before
c) Lipoma of the Filum Terminale :1-Incidence2-Location3-Radiographic Features4-Differential Diagnosis
1-Incidence :-Fatty filum terminale , also known as lipoma of the
filum terminale or filar lipoma-Relatively common finding on imaging of the
lumbar spine and in most cases is an incidental finding of no clinical concern , however , in some patients it may be associated with signs and symptoms of tethered cord syndrome , in such cases it is usually associated with a thickened filum and a low lying conus
2-Location :-Filum terminale
3-Radiographic Features : MRI-A thin filum (>2 mm in diameter at the L5/S1 level)
is rarely symptomatic-When the filum is thickened (with or without fat) it
is much more likely to be associated with a low lying cord (tip of the conus at or below the mid point of L2) and cord tethering ,as such careful assessment of the position of the conus is essential
-The abnormality typically is linear and extends over some distance
-Signal follows that of fat on all sequence
*T1 :-Hyperintense*T2 :-Hypointense*Fat Suppressed Sequences :-Hypointense*T1+C :-No enhancement
T1 T2 T1+C
T1 T2 T1
T1 shows hyperintense mass at the filum terminale and a thin fatty strand extending from the tip of the conus medullaris to the coccyx
T1
T2 with fat suppression shows signal loss of the mass , indicating presence of fat
(A) T1 , (B) T2 & (C) T1+C show the spinal cord ends at L2-L3 level (tethered cord) , It ends in a fatty mass display bright signal intensity in T1 and T2 denoting lipoma , no abnormal enhancement
6-Spinal Metastases :a) Incidence b) Location
a) Incidence :-Approximately 90% of all spinal (cord +
vertebral) neoplasms are considered metastatic in origin
b) Location :1-Vertebral metastases (94%) , may have
epidural extension2-Intradural extramedullary metastases (5%)3-Intramedually metastases (1%)
1-Vertebral Metastases (94%) :a) Incidenceb) Pathologyc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-Must be included in any differential
diagnosis of a bone lesion in a patient older than age 40
-Vertebral metastases are already present in 10% of newly diagnosed cancers , they are much more frequent in higher age groups (<50 years)
-Thoracic spine is the most common site affected
b) Pathology :-The most common primary neoplasms to involved
the vertebrae include :1-Breast cancer2-Lung cancer3-Prostate cancer4-Lymphoma5-Renal cell carcinoma6-Gastrointestinal tract malignancies7-Melanoma
-Primaries with predominantly osteoblastic metastases (sclerotic extradural bone lesions) include :
1-Prostate carcinoma2-Osteosarcoma3-Medullary thyroid carcinoma-Primaries with osteolytic metastases :1-Lung cancer2-Gastrointestinal tract cancers3-Renal cell carcinoma4-Malignant melanoma5-Multiple myeloma
-Primaries with predominantly osteolytic metastases that may rarely become osteoblastic (mixed sclerotic and lytic extradural bone lesions) :
1-Breast cancer2-Lymphoma3-Urothelial carcinoma
c) Radiographic Features :1-Plain Radiography2-CT3-MRI
1-Plain Radiography :- As metastases have a predilection for
involving the posterior vertebral body and pedicle, a missing pedicle (absent pedicle sign) is a useful and subtle sign to seek on AP films
*N.B. :Absent Pedicle Sign :-Also called the winking owl sign , occurs on
plain film when a pedicle is absent , the term , winking owl sign , where the missing pedicle corresponds to the closed eye , the contralateral pedicle to the other open eye and the spinous process to the beak of the animal AP views of the thoracic or lumbar spine
-Etiology :1-Destroyed pedicle :Spinal metastasesIntraspinal malignanciesTuberculosis and other infectionsUncommon : primary bone lesion ; lymphoma2-Congenital absence / hypoplasia of a pedicle3-Neurofibromatosis4-Poorly visualized5-Radiation therapy
Absent right L4 pedicle
Absent LT T11 pedicle
Absent LT L2 pedicle
Absent LT L1 pedicle
2-CT :-Lytic metastases appear as regions of soft
tissue attenuation with irregular margins , the mass may breach the cortex and result in compromise of the spinal canal
-Sclerotic lesions appear hyperdense and irregular but are less likely to extend beyond the vertebrae
With pathologic fracture from breast cancer
3-MRI :-Osteoblastic metastases :*T1 : Hypointense *T2 : Hypointense-Lytic extradural bone lesions :*T1 : Intermediate to hypointense *T2 : Hyper or isointense*T1+C : enhancement usually present-Mixed sclerotic and lytic extradural bone
lesions :*T1 : Hypointense*T2 : Hypo and / or Hyperintense
Osteoblastic Mets
T1
T2
T1+C from RCC
T1+C
With Extension into spinal cord , (A) T1 , (B) T2 (C) & (D) T1+C
d) Differential Diagnosis :-For osteoblastic mets consider :1-Bone islands2-Primary bone tumors (osteoblastoma & osteoid
osteoma)3-Therapy effects (radiation , chemotherapy
& vertebroplasty)-For lytic extradural bone lesions consider :1-Primary bone tumors2-Aneurysmal bone cyst3-Schwannoma4-Infective spondylitis5-Atypical hemangioma
-For mixed sclerotic and lytic extradural bone lesions consider :
1-Primary bone tumors (osteoblastoma & osteoid osteoma)
2-Therapy effects (radiation , chemotherapy & vertebroplasty)
2-Intradural Extramedullary Metastases :a) Incidenceb) Pathologyc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-Rare and only accounts for approximately 5%
of spinal metastases-The age at presentation depends on tumor type ,
metastases from central nervous system malignancies generally occur at a younger age
-In the pediatric population , the most common intradural extramedullary neoplasms are leptomeningeal metastases resulting from primary brain tumors where as in adults non-CNS tumors are most commonly encountered
b) Pathology :-Primary tumors include :1-CNS (drop metastases) :-Cerebral glioblastoma-Anaplastic astrocytoma-Ependymoma and myxopapillary ependymoma-Posterior fossa medulloblastoma (PNET-MB)-Pineal tumors (e.g. germinoma & pineoblastoma)-Choroid plexus neoplasms
2-Non-CNS :-Solid tumors :Lung cancerBreast cancer-Melanoma-Haemopoietic neoplasmsLymphomaLeukemia
c) Radiographic Features :-Plain films and CT are inadequate for
the assessment of possible leptomeningeal metastatic disease and in these cases , MRI is required
-MRI without contrast may be normal and thus when suspected contrast should be administered
*T1 :-Thickened nerve roots or nodular lesions that are
isointense with the spinal cord may be seen
*T2 :-Cord edema may be seen with more extensive
disease , especially if there is an intramedullary component
*T1+C :-Enhancing tumor nodules on the spinal cord ,
nerve roots or cauda equina-(Sugar coating) of the spinal cord and nerve roots
T1+C shows a nodule on leptomeningeal surface
Multiple enhancing nodules are scattered along the cauda equina (blue arrows) with extensive leptomeningeal enhancement of the conus (yellow arrows)
T1+C shows an enhancing nodule and diffuse leptomeningeal enhancement consistent with metastatic medulloblastoma
T1+C shows leptomeningeal metastases with "sugar coating" enhancement
*N.B. :Sugar coating :-Is seen in post contrast images of the brain and spinal cord
in patients with leptomeningeal drop metastases or leptomeningeal carcinomatosis
-It is seen both as a result of CNS involvement from distant primaries as well as direct spread from CNS malignancies
-Primaries :a) Wide spread metastatic disease (more common) :1-Breast cancer2-Lung cancer3-Melanoma4-Lymphoma & Leukemia
b) Primary intracerebral malignancies :1-Cerebral glioblastoma2-Anaplastic astrocytoma3-Ependymoma and myxopapillary ependymoma4-Posterior fossa medulloblastoma (PNET-MB)5-Pineal tumors (e.g. germinoma &
pineoblastoma)6-Choroid plexus neoplasms
d) Differential Diagnosis :*If diffuse (sugar coating) consider :1-Arachnoiditis :-Clumping of nerve roots-Empty sac sign-Often history of prior surgery2-Guillain-Barre syndrome :-Smooth pial enhancement of cauda equina and conus
medullaris-History of recent viral illness is typical3-Meningoradiculitis :-Homogeneously enhancing CSF-CSF correlation useful
*If nodular (mostly at cauda equina) consider : 1-Spinal meningioma :-Multiple meningiomas are most often associated with NF2-Dural tail sign2-Schwannoma :-Multiple schwannomas are often associated with NF2-Frequently associated with hemorrhage , intrinsic vascular
changes , cyst formation and fatty degeneration3-Spinal Neurofibroma :-Multiple neurofibromas are often associated with NF1-Leptomeningeal (pial) lipoma-Follows fat signal intensity-No enhancement4-Post-arachnoiditic adhesions
3-Intramedually Metastases :a) Incidenceb) Pathologyc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-Rare , occurring in 1% of autopsied cancer
patients-Old age (< 55 years)
b) Pathology :-Lung cancer accounts for approximately 50% of cases-Other primary malignancies are breast
carcinoma , lymphoma, leukemia , melanoma , renal cell carcinoma and colorectal carcinoma
-One-third of patients have concomitant brain metastasis and 25% have leptomeningeal metastases
-The most commonly involved location is the cervical cord followed by the thoracic cord and then the lumbar cord , lesions are usually solitary and involve 2-3 vertebral body segments
c) Radiographic Features :MRI-Lesions are usually well-defined and typically produce cord
expansion over several segments, in contrast to primary intramedullary neoplasms , associated cysts are rare
*T1 :-Hypointense*T2 :-Hyperintense , prominent edema commonly surrounds the
tumor nodule*T1+C :-Avid homogeneous enhancement
T1
T2
T1+C
d) Differential Diagnosis :1-Other intramedullary spinal tumors :-Ependymoma-Astrocytoma-Hemangioblasotma2-Inflammatory lesions / transverse myelitis :-Usually longer length of cord involvement-Variable contrast enhancement-Rapidly progressive clinical course3-Multiple sclerosis :-May not demonstrate enhancement-Less prominent cord expansion-Less prominent perilesional edema-Lesions are usually multiple4-Syrinx :-Central cystic lesion-No contrast enhancement