IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM

Department of Radiology 1, CHU Hassan II, Fez.Department of anatomo-pathology2 CHU Hassan II, Fez.

Department of neuro surgery 3 CHU Hassan II, Fez.

F.Z. Belhoussine1, M. Boubbou1, B. Alami1, K.Moumna2, A.Amarti 2, M.Benzegmout3, S. Tizniti1

NR7

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INTRODUCTION:

The anatomy of the supratentoriel midline structures of the brain is complex:• Corpus callosum, • Third ventricle, • Trigone,• Pituitary gland• Pineal gland,…

Different types of tumors can arise from these structures including tumors of the trigone and septum, tumors of the falx, third ventricular tumors and pinal region tumors.

These tumors share similar features: minimal clinical symptoms despite their occasional large size, mild non-specific intracranial hypertension syndrome, value of MRI for depiction of tumor location, stereotactic biopsy, relative difficulty of surgical management.

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OBJECTIVES:

Illustrate the radiological semiology encephalic tumors of the midline.

Show the value of MRI in the exploration of these tumors.

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BACKGROUND:

The anatomy of the supra tentoriel midline structures of the brain is complex.

We can distinguish 4 region:• Sellar and suprasellar region.• Corpus callosum region.• Intraventricular region.• Pineal region.• Falx region.

Brain CT is less sensitive to MRI to contribute for depiction of tumor location, stereotactic biopsy, relative difficulty of surgical management.

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BACKGROUND:

ANATOMY :

Fig B: Sagittal Tl MR ; 4: pineal region , 3: sellar and suprasellar region

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B

1

25

A

Fig A: Coronal Tl MR ; 1: V3 region , 2:corpus callosum region , 5:falx region

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BACKGROUND:

THE MAIN ETIOLOGIES by REGIONS :

Sellar /Suprasellar region

• Microadenoma.• Macroadenoma.• Craniopharyngioma.• Metastasis• Meningioma

Intraventricular ( third

ventricle)• Colloide cyst ( anterior third

ventricle).• Astrocytomas.• Craniopharyngioma.• Hypothalamic astrocytoma.• Suprasellar germinoma (involve

the anterior third ventricular).• Posterior third ventricle: colloid

cyst; meningioma; choroide plexus papillomas; metastases.

Pineal region:

• Pinealomas.• Germinomas.• Teratoma.• Pineocytomas/ pineoblastoma.• Benign cyst

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BACKGROUND:

THE MAIN ETIOLOGIES by REGIONS :

Trigone and corpus callosum region

• Anaplasic astrocytomas.• Glioblastomas.• Lymphoma.• Lipoma• Metastases.

Fax region

• Meningioma.• Metastases.• Hemangiopericytoma

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MATERIALS AND METHODS :

A retrospective study involving 36 patients collected for department of radiology and neuro surgery over 3 years.

Median age is 30 years (2- 77 years).

In all patients conventional magnetic resonance imaging in conjunction with diffusion-weighted imaging (DWI) was performed.

Proton magnetic resonance spectroscopy (MRS) was added in most cases.

MRI examinations were performed in a single session on a machine GE 1.5 Tesla.

Conventional MRI included: sagittal T1, coronal T2, axial FLAIR, axial T2 *, Diffusion, 3 planes T1 gadolinium and sequence spectroscopic.

Histological confirmation was performed in all patients.

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RESULTS :

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42

2222

11

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9

THE SPECTRUM OF DIAGNOSIS FINDINGMeningiomaNeuroglial tumorsAstrocytomascolloid cystEpidermoid cystCraniopharyngomaCh Plexus PapillomaGerminomaLymphomaPineal cystMetastasesMacroadenoma

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RESULTS :

Sellar /Suprasellar region

MRI sagittal section (A) and coronal (D) T2 W1 and coronal T1 without (B) and with gadolinium (C) showing a sellar and suprasellar mass isointense T1, T2 discrete, so is raising homogeneous after contrast.Selected diagnosis: pituitary macroadenoma.

Coronal graphic shows pituitary macroadenoma (open arrow). Indentation from diaphragma sella causes "snowman" appearance (curved arrows). Some cystic degeneration & hemorrhage is depicted.

Anapath : PITUITARY MACROADENOMA

SUPRASELLAR MASS ADULT

A B

C D

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RESULTS :

Sellar /Suprasellar region

MRI in coronal (A) and sagittal (D) T1, coronal T2 (B) and T1 contrast Cornale (c) objectifying the presence of a large sellar and suprasellar process with a heterogeneous isointense T1 (A and D), discrete hyperintense T2 (B), with enhancement of heterogeneously after contrast (C). this process presents an important extension latérosellaire responsible hydrocephalus upstream.

Sagittal graphic shows a predominantly cystic, partially solid, suprasellar mass with focal rim calcifications. Note small intrasellar component and fluid-fluid level.

Anapath : CRANIOPHARYNGIOMA

SUPRASELLAR MASS CHILD

A B

C D

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RESULTS :

Sellar /Suprasellar region

CRANIOPHARYNGIOMA

• Benign dysontogenetic epithelial tumor derived from Rathke pouch epithelium.• Two types: Adamantinomatous and papillary.

• Location:• Surgical division of craniopharyngioma into three groups: Sellar/ Pre

chiasmatic / Retrochiasmatic.• 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 T1WI- Tl C+: Solid portions enhance heterogeneously, cyst walls enhance strongly.

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RESULTS :

Sellar /Suprasellar region

CRANIOPHARYNGIOMA

• Pathology: • Most common pediatric intracranial tumor of non-glial origin.• Approximately 54% of all pediatric sellar/chiasmatic region tumors are CPs

• Clinical Issues:• Clinical profile: Pediatric patient with morning headache, visual defect, short

stature.• Age: Bimodal age distribution (peak 5-15 Years papillary CP > SOy).• 64-96% overall 10 year survival.

• Diagnostic Checklist:• Use NECT to detect Ca++ if MR diagnosis is in question.

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RESULTS :

Sellar /Suprasellar region

Anapath:MENINGIOMA

Fig A,B, C and D show a sphenoid ridge mass slightly intense with cortex in axial and sagittal T1W1(fig A, D) and axial T2W1(Fig C)witch enhance homogeneously & intensely (fig B)

A

B

D

C

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RESULTS :Intraventricular (3rd ventricle)

A

D

C

31 years old. Headaches with visual disturbances neglected for a year. MRI: round lesion of the anterior third ventricle, although limited in homogeneous hyperintense T1 and T2, clogging the holes of Monro, causing a biventricular hydrocephalus active upstream (FLAIR hyper intense peri-ventricular).

Coronal T1 Flair W1

T2

Anapath: COLLOID CYST

Axial graphic shows a classic CC at the foramen of Monro causing mild/moderate obstructivehydrocephalus. Note fornices and choroid plexus are elevated, stretched over the cyst (arrows).

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RESULTS :

Intraventricular (3rd ventricle)

Anapath:PILOCYTIC ASTROCYTOMA

26 years old, Headache, nausea and vomiting, MR find a mass in the third ventricle, hypo intense of Gray matter in T1W1, hyper intense to CSF in Flair and ringlike enhancement of cyst.

A

D

C

Axial FSPGR 3D Coronal T1W1 Gado+ Coronal T1 Flair W1

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RESULTS : Intraventricular (3rd ventricle)

A

D

C

38 years old. Headaches with visual disturbances and vomiting. MRI: Intraventricular Well delineated, lobulated mass in third ventricle iso- intense In T1W1, hyper intense in T2W1, strongly and homogeneously enhanced.

Coronal T1 Flair W1

T2

Anapath: PAPILLOMA

• Typically pediatric tumors, lateral ventricle• In adults, 4th ventricle, third ventricle in 10%• Enhancing papillary mass, hydrocephalus common

SAG t1

COR T1 GADO +COR T2 flair

SAG T1 GADO +

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RESULTS :

Pineal region

A

D

C

14 years old. Headaches with visual disturbances and vomiting. MRI: pineal region mass arround the posterior third ventricle with calcifications in CT, iso- intense In T1W1, hyper intense in T2W1, Slightly hyperintense flair , causing a triventricular hydrocephalus active upstream and homogeneously enhanced.

T2

Anapath: Germinoma

•Engulfs" calcified pineal gland• Intensely enhancing pineal mass, often homogeneous• Often CSF spread at diagnosis• Hyperdense on CT• Typically young male patients

SAG t1 SAG T1 GADO +

Ca+

Axial CT

SAG T1 SAG T1 Gado+

Axial T2 flair

COR T2

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RESULTS :

Pineal region

A

D

C

31 years old.Fainting, convulsive crisis last year. MRI: Round cyst hypo intense T1, hyper intense T2 without calcifications.

T2

PINEAL CYST

•Round, smooth cystic mass• Typically < 1 cm, may be up to 2 cm• Variable calcification and cyst fluid• No or minimal rim enhancement, compressed enhancing gland often seen posteriorly• May be indistinguishable from PC on imaging

SAG t1 SAG T1 GADO +

COR T1 SAG T1 AXIAL T2

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RESULTS :

Pineal region

A

D

C

37 years old. Headache.MRI: lobular mass occupating trijimenal region slightly hyperintense to CSF on T1W1, doesn’t completely null on flair causing triventricular hydrocephalus active upstream, hyper intense on T2 , without enhancement.

T2

Anapath: EPIDERMOID CYST

SAG t1 SAG T1 GADO +

v4

COR T1 COR flair T2

Axial T2

SAGT1 gado +

• Most epidermoid cysts resemble CSF, not fat• No dermal appendages• 4-9x more common than dermoid• Off-midline> midline: 40-50% in CPA, 10-15%para sellar/middle fossa, 10% diploic• MRI: Isointense to CSF except restricts on diffusion

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RESULTS : Pineal region

C

14 years old. Headache..MRI: lobular mass occupating trijimenal region slightly hyperintense to CSF on T1W1 flair, causing triventricular hydrocephalus active upstream, hyper intense on T2 flair, without enhancement.

Coronal T1 Flair W1 Anapath: ASTROCYTOMA LOW GRADE

Cor T2 flair Cor T1 gado+

SAG T1

Axial SPGR

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RESULTS :

Trigone and corpus callosum region

A

D

C

55 years old. Headache and memory troubles.MRI: enhancing lesion involving the entire corpus callosum showing minimal mass effect on the ventricle. Contrast enhanced axial T1W1. Coronal T1 Flair W1

T2

Anapath: LYMPHOMA

SAG t1 SAG T1 GADO +

v4

COR T1 COR flair T2

Axial T2

•Periventricular enhancing mass•Often crosses corpus callosum•Typically iso-intense/hypointense on T2WI• Necrosis common in AIDS related lymphoma.• Intravascular

lymphoma may appear diffusely infiltrating.

Axial flair T1 Axial T2 Axial T1 Gado +

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RESULTS :

Trigone and corpus callosum region

A

D

C55 years old. Headache and memory troubles.MRI: Heterogenous mass involving the entire corpus callosum . It’s hypo intense on T1W1 and shows heteregenous enhancement lesion involving the entire corpus callosum showing minimal mass effect on the ventricle. Contrast enhanced axial T1W1.

T2

Anapath: CORPUS CALLOSUM GLIOMA

SAG t1 SAG T1 GADO +COR T1

Axial T2

Coronal T1 Flair W1 Sagittal T1 TDM axial C+

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CONCLUSION :

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Tumors of the midline of the brain are complex and diverse.

The magnetic resonance imaging is of major interest, allowing a

particularly informative topographic analysis, a diagnostic aid, bringing

sometimes a tissue characterization and support the choice of treatment,

specifying the path and the target in stereotactic biopsies.

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BIBLIOGRAPHY :

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1- A.Osborn, S.Blaser, K.Salzman. Diagnostic Imaging :Brain.

2- Tumeurs cranio encéphalique de la ligne médiane. C.Delmaire; JY.Gauvrit; EL Hajj; G.Soto.Ares; JR2006, 87: 764- 78.

3- Tous en selle sur l’hypophyse. R.Richard, C. Vandendries, F. Benoudiba, N. Hocine, M. Adoui, G. Nasser, D. Ducreux. SFR 2011.

4- Imagerie des tumeurs de la région pinéale : à propos de 26 cas S. Belkacem, M. Fikri, J. Faik Ouahab, N. Ech-Cherif El Kettani, MR. El Hassani, M. Jiddane . SFR2011 .

5- Aide au diagnostic des lésions kystiques intracrâniennes .Y Alaoui Lamrani, M Maâroufi, I Kamaoui, N Hammas, H Ammor, L Benjelloun, M Boubbou, N Sqalli Houssaini, A Amarti, S Tizniti. SFR 2011.

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THANKS