Post on 31-Jan-2022
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