SpineIntraspinal Masses

Mohamed Zaitoun

Assistant Lecturer-Diagnostic Radiology Department , Zagazig University Hospitals

EgyptFINR (Fellowship of Interventional

Neuroradiology)-Switzerlandzaitoun82@gmail.com

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