FORAMEN MAGNUM MENINGIOMA: THE INTEREST OF THE COUPLE CT- M - PowerPoint Presentation

Slide1

FORAMEN MAGNUM MENINGIOMA: THE INTEREST OF THE COUPLE CT- MRI IN THE PRECISE ASSESSMENT OF THE LESION.

S.BELABBES, N.ELYOUSFI, S.CHAOUIR, T.AMIL, A.HANINE , H.EN-NOUALI

Department of Radiology, Military Teaching Hospital Mohammed V of Rabat. Morocco

NR31Slide2

INTRODUCTION

rare, representing 1,8 to 3, 2​​% of intracranial meningiomas.

Among the meningiomas of the posterior fossa, foramen magnum (FM) meningiomas deserve special consideration because of their characteristics in symptomatology, and complications

They are causing a high risk of spinal cord compression.

Several classifications, with a surgical interest, have tried to categorize them according to

dural

attachment, which underscores the value of MRISlide3

CLINICAL CASE

A 33-year-old female

presented with mild headache lasting for a year, neurological examination revealed paresthesia in upper limbs. A CT brain scan and an MRI were performed Slide4

IMAGING DATA

CT showed a process in the level of the foramen magnum spontaneously isodense that enhances after injection of contrast.

CEREBRAL CT C+: large tumor occupies slightly more than half of the transverse diameter of the foramen magnum. the rostral spinal cord is compressedSlide5

IMAGING DATA

MRI objectified a process with broad-base

dural implantation at the expense of the clivus, in isosignal T1 and hypersignal

T2, enhanced after injection of contrast. This process drove back the spinal cord behind, coming in contact with the vertebral artery which is not narrowed. The patient was operated and

anatomopathological

examination found a meningioma of the foramen magnumSlide6

MRI

sagital

section

MRI T1:a large

anterior

foramen magnum

meningioma

isointense

to

surrounding

brain

severely

compresses the

neuraxis

MRI

T2

:

pocess

hyperintense

to surrounding brainSlide7

homogeneously enhancing tumor

arises predominantly

in an anterior locationSlide8

DISCUSSION

Meningiomas are common neoplasms representing 14.3 to 19% of all intracranial tumors.

Slowgrowing benign tumors arising at any location where arachnoid cells reside.

Among

all

the

meningiomas

, only 1.8 to 3.2% arises at the foramen magnum (FM).Slide9

DISCUSSION

DefinitionSlide10

DISCUSSION

The indolent development at the craniospinal junction

makes clinical diagnosis complex and often leads to a long interval between onset of symptoms and diagnosis.Clinical presentation of the FM lesions may be in form of neck pain, dysasthesiasis

in the upper limbs,

quadriparesis

or quadriplegia, cruciate hemiparesis, impaired pain

and touch

sensations and occasionally

pseudoathetoid

movements of the hands. Classic foramen magnum syndrome

is defined by development of unilateral arm sensory and motor deficits, which progress to

the

ipsilateral

leg, then the contralateral leg, and finally contralateral upper extremity.

Clinical

diagnosisSlide11

DISCUSSION

FM meningiomas

arise from arachnoid at the craniospinal junction. The borders of

this zone

, range anteriorly from the lower third of the

clivus

, to upper margin of the body of C-2, laterally

from the

jugular tubercle to the upper margin of the C-2

laminae

, and posteriorly from the anterior edge of the squamous occipital bone to the C-2 spinous

process

.

ClassificationSlide12

DISCUSSION

the classification of these lesions is based on their size relative to that of the foramen

magnum:small, lower than one third the transverse dimension of the foramen magnummedium, one third to one half its

dimension

large

, superior with one

half

Most lesions

arise

anterolaterally

Posterolateral origin is the second most frequent,

P

urely

posterior lesions the

third

The least

common are entirely anterior.

ClassificationSlide13

DISCUSSION

Neuroimaging confirms the clinical diagnosis and allows the planning of a

surgical approach. The diagnosis of FMM is essentially based on morphological criteria

.

It is extra-axial with a large insertion base and obtuse angle connection.

wider

than thick.

The

reaction in the vicinity of bone insertion area is less than

Supratentorial

findings

, but

has a high diagnostic value when it exists in the form of bone erosion or

hyperostosis

NeuroimagingSlide14

DISCUSSION

the decreasing Thickening of the dura and the contrast enhancement "comet tail" adjacent to the meningioma is highly suggestive of meningioma, but not specific, it is met in 59% to 71% of cases.

Magnetic resonance imaging:

Modality

of choice for defining tumors of the

foramen magnum.

provides

high-resolution images of soft-tissue anatomy that is not susceptible

to degradation

by the surrounding skull base, a pitfall of CT scanning.

On T1-weighted image: meningiomas may appear

isointense

, mildly

hypointense

, or

hyperintense to surrounding

brain.

NeuroimagingSlide15

DISCUSSION

On T2-weighted image: isointense to slightly

hyperintense compared with brainThe T1-weighted enhanced contrast imaging shows the

dural

attachment site of the tumor and it provides ready discrimination between

tumor and brainstem

Once the

diagnosis of meningioma

evoked

, MRI should focus on:

locate the tumor in the axial plane at the foramen magnum: anterior, lateral or posterior

define

the compartment where it develops: intra

dural

or extradural or both (in most cases is

intradural

)clarify its relation to the adjacent vertebral artery which can be invaded by the meningioma

NeuroimagingSlide16

DISCUSSION

Other

tumors such as neuromas and metastasisvascular lesions

such

as

vertebro

basilar

aneurysm benign tumors of the clivus especially meningiomas

, and tumors of the jugular foramen extending to the foramen

magnum

Retro

clival

meningioma

that is not always easy to differentiate of the foramen magnum meningioma

Diagnosis differentialSlide17

CONCLUSION

the Foramen magnum meningioma is an uncommon intracranial tumor that presents a particular gravity because of the risk of

bulbo-medullary compression. CT and MRI comprise the essential of current meningioma imaging, and the diagnostic information provided by these modalities is complementary.

MRI

provides excellent soft tissue resolution, while CT far superiorly demonstrates the bone

changes.

The

relationship of the FMM with vertebral artery and the lower cranial nerves is important, and must be mentioned

.Slide18

BIBIOLOGRAPHY

1- L Pierot, A Boulin, A Guillaume,F

Pombourcq. IMAGERIE DES TUMEURS DE LA BASE DU CRÂNE DE L’ADULTE. J Radiol 2002;83:1719-34.2- M A.

Barnadas

, A.

Escartín

, A

Alomar

. Oral

ulcerations

as the first sign of a foramen magnum meningioma

. Oral

Surg

Oral Med Oral

Pathol

Oral

Radiol Endod 2000;90:609-11.3- Bassiouni

H, Ntoukas V, Asgari S, Sandalcioglu EI, Stolke D, Seifert V.Foramen magnum meningiomas: clinical outcome after microsurgical resection via a posterolateral suboccipital retrocondylar approach. Neurosurgery. 2006 Dec;59(6):1177-85; discussion 1185-74- de Tella OI Jr, de Paiva Neto MA, Aguiar PH, Herculano MA.Anterior

and

lateral

foramen magnum

meningiomas

Arq

Neuropsiquiatr

. 2006 Jun;64(2B):437-40

5- Michaël Bruneau , Bernard George. Foramen magnum

meningiomas

:

detailed

surgical

approaches

and

technical

aspects

at

Lariboisière

Hospital

and

review

of the

literature

.

Neurosurg

Rev

2007 Sep 20; [

Epub

ahead

of

print

].

6-E L.

Gasparetto

; CC.

CLeite

; LT.

Lucato

; CV de

Barros

; S K.N. Marie; P.

SantanaII

; PHP de

Aguiar

; S.

Rosemberg

.

Intracranial

meningiomas

:

magnetic

resonance

imaging

findings

in 78 cases.

Arq

. Neuro-

Psiquiatr

. vol.65 no.3a São Paulo Sept. 2007.