IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS

IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM F. Z. Belhoussine 1, M. Boubbou 1, B. Alami 1, K. Moumna 2, A. Amarti 2, M. Benzegmout 3, S. Tizniti 1 Department of Radiology 1, CHU Hassan II, Fez. Department of anatomo-pathology 2 CHU Hassan II, Fez. Department of neuro surgery 3 CHU Hassan II, Fez. NR 7

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. IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 1 of 25

OBJECTIVES: Illustrate the radiological semiology encephalic tumors of the midline. Show the value of MRI in the exploration of these tumors. IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 2 of 25

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. IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 3 of 25

BACKGROUND: ANATOMY : 5 2 1 4 3 B A Fig A: Coronal Tl MR ; 1: V 3 region , 2: corpus callosum region , 5: falx region Fig B: Sagittal Tl MR ; 4: pineal region , 3: sellar and suprasellar region IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 4 of 25

BACKGROUND: THE MAIN ETIOLOGIES by REGIONS : Sellar /Suprasellar region • • • Microadenoma. Macroadenoma. Craniopharyngioma. Metastasis Meningioma Pineal region: • • • Pinealomas. Germinomas. Teratoma. Pineocytomas/ pineoblastoma. Benign cyst 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. IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 5 of 25

BACKGROUND: THE MAIN ETIOLOGIES by REGIONS : Trigone and corpus callosum region • • • Anaplasic astrocytomas. Glioblastomas. Lymphoma. Lipoma Metastases. Fax region • Meningioma. • Metastases. • Hemangiopericytoma IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 6 of 25

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 T 1, coronal T 2, axial FLAIR, axial T 2 *, Diffusion, 3 planes T 1 gadolinium and sequence spectroscopic. Histological confirmation was performed in all patients. IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 7 of 25

RESULTS : THE SPECTRUM OF DIAGNOSIS FINDING 4 9 6 1 1 4 1 2 2 2 Meningioma Neuroglial tumors Astrocytomas colloid cyst Epidermoid cyst Craniopharyngoma Ch Plexus Papilloma Germinoma Lymphoma Pineal cyst Metastases Macroadenoma IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 8 of 25

RESULTS : Sellar /Suprasellar region A B C D SUPRASELLAR MASS ADULT MRI sagittal section (A) and coronal (D) T 2 W 1 and coronal T 1 without (B) and with gadolinium (C) showing a sellar and suprasellar mass isointense T 1, T 2 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 IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 09 of 25

RESULTS : Sellar /Suprasellar region A B C D SUPRASELLAR MASS CHILD MRI in coronal (A) and sagittal (D) T 1, coronal T 2 (B) and T 1 contrast Cornale (c) objectifying the presence of a large sellar and suprasellar process with a heterogeneous isointense T 1 (A and D), discrete hyperintense T 2 (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 IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 10 of 25

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 T 1 WI - Tl C+: Solid portions enhance heterogeneously, cyst walls enhance strongly. IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 11 of 25

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. IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 12 of 25

RESULTS : Sellar /Suprasellar region D A Fig A, B, C and D show a sphenoid ridge mass slightly intense with cortex in axial and sagittal T 1 W 1(fig A, D) and axial T 2 W 1(Fig C)witch enhance homogeneously & intensely (fig B) C Anapath: MENINGIOMA B IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 13 of 25

RESULTS : Intraventricular (3 rd ventricle) T 2 Axial graphic shows a classic CC at the foramen of Monro causing mild/moderate obstructive hydrocephalus. Note fornices and choroid plexus are elevated, stretched over the cyst (arrows). D A 31 years old. Headaches with visual disturbances neglected for a year. MRI: round lesion of the anterior third ventricle, although limited in homogeneous hyperintense T 1 and T 2, clogging the holes of Monro, C causing a biventricular hydrocephalus active upstream (FLAIR hyper intense periventricular). Coronal T 1 Flair W 1 Anapath: COLLOID CYST IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 14 of 25

RESULTS : Intraventricular (3 rd ventricle) D A Coronal T 1 W 1 Gado+ Axial FSPGR 3 D Coronal T 1 Flair W 1 C 26 years old, Headache, nausea and vomiting, MR find a mass in the third ventricle, hypo intense of Gray matter in T 1 W 1, hyper intense to CSF in Flair and ringlike enhancement of cyst. Anapath: PILOCYTIC ASTROCYTOMA IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 15 of 25

Intraventricular (3 rd ventricle) RESULTS : T 2 38 years old. Headaches with visual disturbances and vomiting. MRI: Intraventricular Well delineated, lobulated mass in third ventricle iso. Dintense In T 1 W 1, hyper intense in T 2 W 1, strongly and homogeneously enhanced. SAG A t 1 SAG T 1 GADO + • Typically pediatric tumors, lateral ventricle • In adults, 4 th ventricle, third ventricle in 10% • Enhancing papillary mass, hydrocephalus common C Coronal T 1 Flair W 1 COR T 2 flair Anapath: PAPILLOMA COR T 1 GADO + IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 16 of 25

RESULTS : Ca+ Pineal region T 2 Axial CT D SAG T 1 A SAG t 1 SAG T 1 Gado+ SAG T 1 GADO + 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 T 1 W 1, hyper intense in T 2 W 1, Slightly hyperintense flair , causing a triventricular hydrocephalus C active upstream and homogeneously enhanced. Axial T 2 flair • Engulfs" calcified pineal gland • Intensely enhancing pineal mass, often homogeneous • Often CSF spread at diagnosis • Hyperdense on CT • Typically young male patients Anapath: Germinoma COR T 2 IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 17 of 25

RESULTS : Pineal region T 2 D A SAG t 1 SAG T 1 GADO + SAG T 1 COR T 1 AXIAL T 2 31 years old. Fainting, convulsive crisis last year. MRI: Round cyst hypo intense T 1, hyper intense T 2 without calcifications. • 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 C PINEAL CYST IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 18 of 25

RESULTS : • Most epidermoid cysts resemble CSF, not fat • No dermal appendages • 4 -9 x more common than dermoid • Off-midline> midline: 4050% in CPA, 10 -15% para sellar/middle fossa, 10% diploic • MRI: Isointense to CSF except restricts on diffusion Pineal region T 2 Axial T 2 D COR T 1 A SAG t 1 COR flair T 2 SAG T 1 GADO + 37 years old. Headache. MRI: lobular mass occupating trijimenal region slightly hyperintense to CSF on T 1 W 1, doesn’t completely null on flair causing triventricular hydrocephalus active upstream, hyper intense on T 2 , without enhancement. C v 4 SAGT 1 gado + Anapath: EPIDERMOID CYST IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 19 of 25

RESULTS : Pineal region SAG T 1 Cor T 2 flair Cor T 1 gado+ 14 years old. Headache. . MRI: lobular mass occupating trijimenal region slightly hyperintense to CSF on T 1 W 1 flair, causing triventricular hydrocephalus active upstream, hyper intense on T 2 flair, without enhancement. C Coronal T 1 Flair W 1 Anapath: ASTROCYTOMA LOW GRADE Axial SPGR IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 20 of 25

RESULTS : Trigone and corpus callosum region T 2 Axial T 2 D COR T 1 A SAG t 1 Axial flair T 1 COR flair T 2 SAG T 1 GADO + Axial T 2 v 4 Axial T 1 Gado + 55 years old. Headache and memory troubles. MRI: enhancing lesion involving the entire corpus callosum showing minimal mass C effect on the ventricle. Contrast Coronal T 1 Flair W 1 enhanced axial T 1 W 1. • Periventricular enhancing mass • Often crosses corpus callosum • Typically isointense/hypointense on T 2 WI • Necrosis common in AIDS related lymphoma. • Intravascular lymphoma may appear diffusely infiltrating. Anapath: LYMPHOMA IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 21 of 25

RESULTS : Trigone and corpus callosum region T 2 Axial T 2 D COR T 1 A SAG t 1 Sagittal T 1 SAG T 1 GADO + Coronal T 1 Flair W 1 TDM axial C+ 55 years old. Headache and memory troubles. C involving the entire corpus callosum. It’s hypo intense on T 1 W 1 and shows MRI: Heterogenous mass heteregenous enhancement lesion involving the entire corpus callosum showing minimal mass effect on the ventricle. Contrast enhanced axial T 1 W 1. Anapath: CORPUS CALLOSUM GLIOMA IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 22 of 25

CONCLUSION : Tumors of the midline of the brain are complex and diverse. The magnetic resonance imaging is of major interest, allowing a COR T 1 A SAG t 1 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. IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 23 of 25

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COR T 1 A SAG t 1 THANKS IMAGING OF MIDLINE TUMORS OF THE CENTRAL NERVOUS SYSTEM 25 of 25