Post on 19-Dec-2015
transcript
Ciprian Gradinaru MD, Mark Kelly MD Brent Griffith MD, Suresh Patel MD
Division of NeuroradiologyHenry Ford Health System
• The skull base anatomy can be divided into the anterior, middle and posterior compartments
• Tumors can arise from skull base structures or extend into the skull base region from intra or extra cranial lesions
• Skull base tumors offer a number of unique challenges:• Deep location
• Complex anatomy (neurovascular foramina, adjacent structures)
• Close proximity to eloquent structures (brain, orbit, CN’s, vessels)
• Diverse pathology (benign/malignant tumors, infectious, congenital)
• The osseous skull base and pachymeninges (dura mater) are effective barriers, but tumor can spread through skull base foramina
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• Lesion evaluation• Anatomic localization
• Extent of disease
• Pattern of growth (benign vs. aggressive)
• Imaging characteristics
• Prognostic information• Disease staging
• Morbidity and mortality
• Treatment planning• Biopsy/surgical approach
• Need for adjuvant therapy
• Treatment Follow-up• Treatment response and effects
• Recurrence and progression of disease
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CT
•Can be performed quickly
•Excellent anatomic detail of osseous structures
•Information regarding lesion aggressiveness (smooth remodeling vs. erosion of adjacent bone)
•Multi-planar reconstructions in any imaging plane from single acquisition
•Requires ionizing radiation
MR
•Longer scan times.
•Excellent evaluation of soft tissues
•Involvement of neurovascular structures.
•Need multiple imaging pulse sequences for characterization of lesions
•Prone to artifact (especially at skull base)
•No radiation
CT and MR play a complimentary role.
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Anatomic Location
•The skull base is generally grouped into anterior, middle, and the posterior cranial fossae
•Location-based classification is helpful because:
• Regional specificity of certain tumor types
• Similar clinical findings
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Anterior Cranial Fossa
•Cancers of the paranasal sinuses or nasal cavity are the most common malignant tumors
•Tumor examples:• Meningioma• Esthesioneuroblastoma• Sino-nasal (SN) malignancies• Giant cell tumor (GCT)• Hemangiopericytoma• Multiple myeloma (MM)/plasmacytoma• Sarcomas (Osteo. and Rhabdo.) • Lymphoma• Melanoma
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Middle Cranial Fossa
•Central region:• Pituitary adenoma, meningioma, pseudotumor, craniopharyngioma, sphenoid sinus carcinoma
•Clival region:• Chordoma, meningioma, paraganglioma, naso-pharyngeal (NP) carcinoma, schwannoma, chondrosarcoma, MM/plasmacytoma, pseudotumor
•Para-central/Cavernous Sinus region:• Meningioma, schwannoma, adenoid cystic carcinoma (ACC), NP carcinoma, GCT, pseudotumor
•Petro-Clival/Lateral region:• Meningioma, schwannoma, NP angiofibroma, ACC, sarcoma, acquired/congenital cholesteatoma, cholesterol granuloma, pseudotumor
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Posterior Cranial Fossa
•Cerebellopontine (CP) angle: • Schwannoma, meningioma, epidermoid,
arachnoid cyst, cholesterol granuloma, endo-lymphatic sac tumor, metastasis, leptomeningeal and granulomatous process
•Jugular foramen: • Paraganglioma, schwannoma, meningioma,
metastasis
•Foramen magnum: •Meningioma, schwannoma, chordoma, intra-medullary cord tumor, neurenteric cyst
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Behavior – Benign or Aggressive?•Osseous changes
• CT smooth remodeling vs. permeative/destructive pattern
• MR bone marrow involvement (T1 signal abnormality)
Smooth Remodeling (Pituitary Macro-adenoma)
Permeative/Destructive(Sarcoma)
T1 Marrow Replacement(NP Carcinoma)
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Behavior – Benign or Aggressive?•Osseous changes
•Tumor cellularity (high)• T2WI hypo to iso-intense signal compared to gray matter
• DWI/ADC restricted diffusion
Restricted Diffusion(Meningioma)
Iso-intense T2 signal(Esthesioneuroblastoma)
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Behavior – Benign or Aggressive? •Osseous changes
•Tumor cellularity
•Intra-lesion contents (hemorrhagic or necrotic components)•T1WI pre hyper-intense signal (hemorrhage)
•T1WI post non-enhancing necrotic tissue
Central Necrosis(Chondrosarcoma)
T1 Pre T1 Post
Hemorrhage(Chondroblastoma)
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Behavior – Benign vs. Aggressive?
•Osseous changes
•Tumor cellularity
•Intra-lesion contents
•Tumor margins• MRI best on T2wi and post T1wi
• Well-defined/smooth Benign
• Ill-defined/infiltrative Aggressive
Well-defined (Meningioma)
Ill-defined (AdenoCa)
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Extension•Extra-cranial vs. Intra-cranial
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SN Neuroendocrine Carcinoma (SNEC) Meningioma
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Extension•Extra-cranial vs. Intra-cranial
•Direct vs. Indirect (perineural)
• Skull base bone and pachymeninges (dura mater) act as barrier
• Neurovascular foramina and cranial nerves provide conduit
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http://www.imaios.com/Media/Images/e-anatomy/Cranial-nerves-anatomy-diagrams/skull-cranial-base-foramen-cranial-nerves-anatomy-en
Extension•Perineural involvement includes perineural invasion and spread
• Perineural invasion microscopic feature of malignancy is often confined to the main tumor mass
• Perineural spread clinico-radiologic observation of distant spread of tumor via perineural spaces or within the nerve sheath/nerve itself
•Most often seen with extra-cranial squamous cell carcinoma
•Most commonly seen with salivary gland tumors (mainly ACC and Muco-epidermoid carcinoma)
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Extension
Imaging of Peri-neural Involvement
• Focal/segmental/diffuse enhancement and enlargement of the cranial nerve
• Skull base foramen enlargement and replacement of the normal fat within the foramen
• Look for denervation atrophy of the muscles supplied by the involved cranial nerve
Heterogeneously enhancing mass of the left parotid gland (Mucoepidermoid Carcinoma) with enlargement and enhancement of the left facial nerve as it enters the stylomastoid foramen (normal right facial nerve)
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Integrity of Eloquent Structures•Dural, leptomeningeal and parenchymal invasion
• T1WI (post-contrast) and T2WI/FLAIR are best
• Leptomeningeal or dural enhancement (nodular or linear > 5 mm)
• Enhancement or edema of brain adjacent to tumor
SN Poorly Differentiated Adenocarcinoma
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Integrity of Eloquent Structures•Dural, leptomeningeal and parenchymal invasion
•Skull base foramina and contents
• Foraminal anatomy is key
• MRI Loss of normal fat and enhancement within neuroforamina
• CT Helpful for evaluation of osseous walls of neuroforamina
Left cavernous sinus meningioma spreading into the left masticator space via the left foramen ovale and into the left pterygopalatine fossa via the left foramen rotundum
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Integrity of Eloquent Structures•Dural, leptomeningeal and parenchymal invasion
•Skull base foramina and contents
•Orbit and optic nerve
• Orbital fissures and apex are most commonly involved• Periorbital and CN-II dural sheath closely related at orbital apex
Lymphoma encasing left optic nerve
Meningioma invading the left orbital apex
Enhancing soft tissue replacing fat within a widened right superior orbital fissure
(Meningioma)
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Integrity of Eloquent Structures•Dural/Parenchymal invasion
•Skull base foramina and contents
•Orbit and optic nerve
•Cavernous sinus (CS) involvement
• Loss of normal CS enhancement
• Convex bulging of the lateral wall of the CS (normally concave)
Nasopharyngeal SCC
Invasive Pituitary Macroadenoma
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Location• Floor of the anterior cranial fossa
Behavior • Hyperostosis of adjacent skull base
(non-aggressive)
• Hyperdense mass (indicates high cellularity, but not behavior)
Extension• Intact skull base without evidence
of extra-cranial extension
Eloquent Structures • Compression of the bilateral frontal
lobes with vasogenic edema
• Effacement of the frontal horn of the right lateral ventricle
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Location• Floor of the anterior cranial fossa
Behavior • Homogeneous enhancement
• Restricted diffusion (indicates high cellularity, but not behavior)
Extension• Intact skull base without evidence of
extra-cranial extension
Eloquent Structures • Compression of the bilateral frontal
lobes
• Displacement of vessels
Location• Tumor is centered in the superior
olfactory recess region
Behavior • Homogeneous solid enhancement
• Destroys the cribriform plate, bilateral ethmoid air cells, nasal septum as well as the bilateral superior and middle nasal conchae
Extension• Tumor extends into the floor of the
anterior cranial fossa
• Post obstructive changes in the left frontal sinus
Eloquent Structures • Slight mass effect on the bilateral
infero-medial frontal lobes
• Preserved medial orbital walls
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Location• Large mass centered in sinonasal cavity
Behavior • Poorly defined tumor margins
• Destruction of the cribriform plate, bilateral medial orbital walls, nasal cavity, ethmoid air cells and maxillary sinuses
Extension• Tumor extends into the infero-medial
anterior cranial fossa, bilateral medial orbits and bilateral maxillary sinuses
Eloquent Structures • Compression of the bilateral infero-medial
frontal lobes with vasogenic edema
• Mass effect on the bilateral medial rectus muscles
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T1 Post
T1 Pre
T2 FS
Location• Large mass centered in sinonasal cavity
Behavior • Heterogeneous enhancement
• Irregular tumor margin
Extension• Superior extension into the anterior
cranial fossa
• Extends into bilateral medial orbits and maxillary sinuses
Eloquent Structures • Compression of bilateral frontal lobes
with vasogenic edema
• Mass effect on medial rectus muscles
• Mass effect on optic chiasm
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Location• Large mass (> 10mm) centered in the
central/para-central middle cranial fossa
Behavior • Homogeneous avid enhancement
• Smooth well defined margins
Extension• Left cavernous sinus with convex lateral bulge
• Supra-sellar region
Eloquent Structures • Encasement of the left internal carotid artery
• Mass effect on the optic chiasm
• Mass effect on anteromedial left temporal lobe
• Slight flattening of the left anterior pons
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Location• Midline mass originating from the clivus
Behavior • Infiltrative mass with irregular margins
• Bony destruction
Extension• Anteriorly into sphenoid sinuses,
ethmoid air cells, and nasal cavity
• Posteriorly into pre-pontine cistern
• Superorly into sellar/supra-sellar region
• Inferiorly into nasopharynx
• Left lateral into medial middle cranial fossa and left maxillary sinus
Eloquent Structures• Mass effect on antero-medial left
temporal lobe
• Slight flattening of anterior pons
• Mass effect on pituitary gland
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Location• Midline mass originating from the clivus
Behavior • Infiltrative mass with irregular margins
(aggressive)
Extension• Anteriorly into sphenoid sinuses,
ethmoid air cells, and nasal cavity
• Posteriorly into pre-pontine cistern
• Superorly into sellar/suprasellar region
• Inferiorly into nasopharynx
• Left lateral into middle cranial fossa
Eloquent Structures• Mass effect on medial left temporal lobe
• Slight flattening of the anterior pons
• Mass effect on the pituitary gland
Location• Mass located in the right para-central
middle cranial fossa
Behavior • Homogeneously enhancing mass
• Smooth widening of the right superior and inferior orbital fissures (non-aggressive)
• Hyperostosis of the greater wing of the right sphenoid bone (non-aggressive)
Extension• Right orbital apex
• Right superior and inferior orbital fissures
• Right pterygopalatine fossa
Eloquent Structures • Neurovascular structures involving right
cavernous sinus, superior orbital fissure and pterygopalatine fossa
• Compression of optic nerve at orbital apex
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Location• Mass located in the right para-central
middle cranial fossa
Behavior • Homogeneously enhancing mass with
smooth margins (non-aggressive)
• Widening of right pterygomaxillary fissure
Extension• Right pterygopalatine fossa (replacement
of fat on precontrast T1)
Eloquent Structures • Encasement and narrowing of the right
internal carotid artery
• Slight compression of the medial right temporal lobe
• Other neurovascular structures within the cavernous sinus and pterygopalatine fossa
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Location• Soft tissue density involving the left
pterygopalatine fossa
Behavior • Intense FDG uptake on PET
• Widening of the left sphenopalatine foramen and left pterygomaxillary fissure
• Bony erosion (aggressive) of posterior left maxillary sinus wall and left pterygoid plate
Extension• Left inferior orbital fissure
• Left pterygopalatine fossa (replacement of fat on CT)
Eloquent Structures • Neurovascular structures within the left
pterygopalatine fossa and inferior orbital fissure
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Location• Lesion centered at the left petro-occipital
fissure
Behavior • Permeative osseous destruction of the
clivus and left petrous apex (aggressive)
Extension• Erosion of the wall of the left carotid
canal
• Anterior aspect of the left jugular foramen
Eloquent Structures • Potential involvement of left internal
carotid artery
• Neurovascular structures within the left jugular foramen
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Location• Mass centered at the left petro-occipital
fissure
Behavior • Heterogeneous enhancement with
areas of central necrosis
Extension• Involvement of the clivus and left
petrous apex
• Extension into the left pre-pontine and cerebello-pontine cisterns
Eloquent Structures • Compression of the pons
• Close proximity to the basilar artery
• Focal encasement of the left internal carotid artery
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Location• Mass centered within the region of the
left jugular foramen
Behavior • Moth-eaten bony destruction
(aggressive) of the left jugular foramen walls and posteromedial aspect of the left middle ear cavity
Extension• Posteromedial aspect of the left
middle ear cavity
Eloquent Structures • Neurovascular structures coursing
within the left jugular foramen (pars nervosa and pars vascularis)
• Left middle ear structures
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Location• Mass centered within the region of
the left jugular foramen
Behavior • Heterogeneous enhancement
Extension• Left jugular foramen (pars nervosa
and pars vascularis)
• Left sigmoid sinus
Eloquent Structures • Neurovascular structures within the
left jugular foramen (pars nervosa and pars vascularis)
• Left sigmoid sinus
• Left middle ear structures
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Location• Mass in the posterolateral aspect of the
left petrous temporal bone
Behavior • Partially cystic mass with enhancement of
the non-cystic component
• No restriction diffusion
• Erosive changes of the posterior left petrous temporal bone (aggressive)
Extension• Left cerebello-pontine cistern
• Left vestibular aqueduct is not identified
Eloquent Structures• Slight mass effect on the left cerebellum
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• Large variety of pathology histological diagnosis by imaging is not possible.
• Imaging plays important role in evaluation:• Anatomic localization and extent of disease
• Biologic behavior (benign vs. aggressive)
• Involvement of adjacent eloquent structures
• Treatment planning (3-D surgical navigation)
• Post-treatment morbidity and mortality
• Follow-up post-treatment
• Complex anatomy and diverse pathology• Systematic approach for evaluating skull base tumors is important
• Location and behavior can help shorten the differential diagnosis
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1.Erdem E et al: Comprehensive review of intracranial chordoma. Radiographics. 23(4):995-1009, 20032.Nakasu Y et al: Tentorial enhancement on MR images is a sign of cavernous sinus involvement in patients with sellar tumors. AJNR Am J Neuroradiol. 22(8):1528-33, 20013.van den Berg R: Imaging and management of head and neck paragangliomas. Eur Radiol. 15(7):1310-8, 20054.Razek AA et al: Imaging lesions of the cavernous sinus. AJNR Am J Neuroradiol. 2009 Mar;30(3):444-52. Epub 2008 Dec 18. Review. Erratum in: AJNR Am J Neuroradiol. 30(7):E115, 2009D5.Schmidinger A et al: Natural history of chondroid skull base lesions--case report and review. Neuroradiology. 44(3):268-71, 2002D6.Lo WW et al: Endolymphatic sac tumors: radiologic appearance. Radiology. 189(1):199-204, 19937.Chong VF et al: Nasopharyngeal carcinoma. Eur J Radiol. 66(3):437-47, 2008D8.Yu T et al: Esthesioneuroblastoma methods of intracranial extension: CT and MR imaging findings. Neuroradiology. 51(12):841-50, 2009D9.Harnsberger R, Hudgins R, Wiggins P, et al. Diagnostic Imaging: Head and Neck. Salt Lake City, Utah: Amirsys, Inc. 2004.
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