Skull Base Tumors

Zoran Rumboldt

University of RijekaMedical University of South Carolina

Telemedicine Clinic

DISCLOSURE

I have no actual or potential conflict of interest

in relation to this presentation

Tumors arising from the tissues of the skull baseAny mass that involves (or abuts) the base of skull

Primary bone and cartilage lesions may not always bedistinguished from those originating above (intracranial) or below (neck, paranasal sinuses, orbits)

Other conditions can mimic neoplasms

Lesions that can occur anywhere in the skull base

Lesions that are typical for a certain region

DEFINITION

Anterior Fossa(frontal sinuses to sphenoidal ridge & planum sphenoidale)

- sinonasal and orbital masses- intracranial lesions

Middle Fossa (sphenoidal ridge to petrous ridge) :

Central Skull Base - chordoma & chondrosarcoma- sella & perisellar masses- nasopharyngeal & sinonasal lesions

Lateral / Temporal - petromastoid (ear mass lesions)

Posterior Fossa(behind petrous ridge and clivus)

Location / Origin of a Lesion

Specific Imaging Findings

Patient’s Age

Juvenile Nasopharyngeal Angiofibroma Paget’sMetastatic Neuroblastoma Plasmacytoma

The extent of the lesion & its relationship to vital structures

Osteolytic & Osteoblastic

Patterns

Lesion MarginsDensity/Intensity

EnhancementPatterns

DWI - ADC

Skull Base Anatomy

IMAGING TECHNIQUE

CTBONE window and ALGORITHM/FILTER thinnest possible slices (detector width)SOFT TISSUE window and algorithmthicker (3mm) slices, post contrast

MRIT1-weighted images WITHOUT FAT SATURATION

T2-weightedSTIR

Post contrast T1-weighted w/o & with fat saturation T2w

T1w no FSCT bone filter & window

T1wno FS

Neurosurgery 2018; 82: 255

Pol J Radiol 2017; 82: 398

T1wGd

Bone Marrow changes with Age

Kunimatsu A, et al.Pol J Radiol 2017; 82: 398-409

3 months 30 months 5 years

T1w

Anterior Cranial Fossa

- sinonasal and orbital masses

- intracranial lesions

T2w

FLAIRT1w T1wGd

T1wGd

Olfactory Meningioma

Olfactory Neuroblastoma

Centered at cribriform plateIntracranial cystic areas

T2w

T1w

T1wGd

EthmoidMucocele

Completely opacifiedand expanded sinus (cell)

T2w

FLAIR

T1w

T1wGd

Allergic Fungal Sinusitis

NECT

AFS

(BL) Expanded Sinuseswith Hyperdense Stuff

Images/Symptoms MismatchTeenagers

Middle Cranial Fossa

Central Skull Base- chordoma & chondrosarcoma

- sella & perisellar masses

- nasopharyngeal & sinonasal lesions

PituitaryAdenoma

T1w Gd

through sellar floorfilling sphenoid sinus

T1w GdT1w

NPC

from nasopharynx - marrow infiltration, then destruction

Encephalocele

IIH - IdiopathicIntracranial

Hypertension

T2w

from intracranial hypertension

Sternberg’s canal

Int Forum Allergy Rhinol 2014;4:246-50. doi: 10.1002/alr.21262

Lateral sphenoidencephaloceles

NOT the cause of

Persistent Craniopharyngeal Canaleal Ca

(Inferior Median)Clival Canal

Clival CanalCanalis Basilaris Medianus

Fossa Navicularis

T2w

T2w

FLAIR

T1w

EcchordosisPhysaliphora

EP - thought to be a remnant of notochord

EcchordosisPhysaliphora

T2w

T1wGd

AJNR 2004; 25:1851

Chordoma

from ClivusOsteolyticHypodense Mass

protruding intoBrainstem

Very high T2

T1w

T2w

Chordoma

Very high ADC(unless high grade)Variable (minimal)

enhancement

T1w

T2w T1w Gd

ADC

Chondrosarcoma

T2w

T1w GdADC

Typical stippledenhancementVery High ADC

from petroclival junction(synchodrosis – cartilage)Whirls of calcs (in 50%)

ChondrosarcomaT2w

T1w Gd

NECT

Chordoma

may be off midlineand not differentiatedfrom Chondrosarcoma

Plasmacytytoma

Oval with sharp marginsClivus & Petroclival

T2wT1w

T1wFS Gd

PlasmacytytomaOval with sharp marginsClivus & Petroclival

T2w

Fibrous DysplasiaGround glass (+ cystic/lytic) with preserved cortical bone

MRI may be confusing – variable signal/enhancement

T1w Gd

T2w T1w Sellar Meningioma

T2 2 isoo to o hypointensese, “““duralal tail”, narrows ICA

T2w

T1w Gd

Hemangioma of the Cavernous Sinus

very bright on T2WI & ADC, avidly enhances

T1w GdT2wT1w

ADC

Hemangioma Hemangioma of the Cavernous Sinus

very high T2 signal, enhances like vessels

CTA

Middle Cranial Fossa

Lateral / Temporal- petromastoid (ear mass lesions)

FibrousDysplasia

No extraosseousenhancing mass

Ground glassPreserved cortexT1w

T2wT1wGd

IntraosseousMeningioma

T1w Gd CECT

Reactive cortical bone changesDensely enhancing

extraosseous portion

Meningioma

Intra&

Extra Cranial

T1w

T1wGd

T2w

4yo girl with a rapidly enlarging mass

T1w FS Gd

T2w

ADC

Metastatic NeuroblastomaOsteosarc - likeLow Diffusion

Temporal/OrbitYoung Child

Scan the belly

Glomus Jugulare

Enhancing Mass with Flow voidsInfiltrative Osteolysis

T2w T1w Gd

at Jugular Foramen

Glomus Jugulare

3D TOF

T2w T1w w Gd

Jugular SchwannomaADC

T2w

T1w T1w w FS Gd

Smooth bone remodelingHigh ADC & T2Avid enhancementNo flow voids

Location - Direction!

CN VII Schwannoma

alongFacialnerve

Location!CN VII

Ganglion

RetrocochlearInfiltrativeOsteolytic mass

centered atEndolymphaticduct/sac

Endolymphatic Sac Tumor

T1wGd

T2w T1w

HighT1 & T2

VHL ?

Cholesterol Granuloma

T1w Gd

T1w T2w

T2*

Smooth sharppetrous apex

expansionT1 & T2 hyper

Anterior Fossa(frontal sinuses to sphenoidal ridge & planum sphenoidale)

- sinonasal and orbital masses- intracranial lesions

Middle Fossa (sphenoidal ridge to petrous ridge) :

Central Skull Base - chordoma & chondrosarcoma- sella & perisellar masses- nasopharyngeal & sinonasal lesions

Lateral / Temporal - petromastoid (ear mass lesions)

Posterior Cranial Fossa

Posterior Condylar Canal

Occipital emissary vein

Epidermoid(Cholesteatoma)

T2w DWI

CSF-like onCT, T1w & T2wDWI bright

ArachnoidGranulations

Along sinusesLobulated bone remodelingNot always T2 bright

Lymphoma

T2w

T1w GdT1w

Bone Infiltration

withoutdestruction

Not T2 brightHomogenousenhancement

Lowdiffusion

ADC dark

Insights Imaging 2018; 9: 84

Location / Origin of a Lesion

Specific Imaging Findings

Patient’s Age

The extent of the lesion & its relationship to vital structures

Osteolytic & Osteoblastic

PatternsMargins

Density/Intensity

EnhancementPatterns

DWI - ADC

Know YourSkull Base Anatomy