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SKULL BASE REVIEW AND PATHOLOGY Melissa Durand Hartford Hospital Noon Conference October 20, 2006

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Page 1: Skull Base

SKULL BASE

REVIEW AND PATHOLOGY

Melissa Durand

Hartford Hospital Noon Conference

October 20, 2006

Page 2: Skull Base

Skull Base Anatomy Review

Skull Base Boundaries

• Upper surface of ethmoid bones and orbital plate of frontal bone to the occiptal bone

Three Key Bones

• Sphenoid

• Temporal

• Occipital

Page 3: Skull Base

Skull Base Anatomy Review

Temporal Bone

Temporal bone- petrous portion

Sphenoid Bone

Occipital BoneKey Fissures

• Petrosphenoidal fissure

• Petrooccipital fissure

Key Sutures

• Sphenosquamous Suture

• Occipitomastoid Suture

Page 4: Skull Base

Skull Base Anatomy Review

Key Openings

• Foramen spinosum

• Foramen ovale

• Foramen lacerum

• Foramen rotundum

• Foramen magnum

• Foramen of vesalius

• Jugular foramen

• Superior orbital fissure

• Inferior orbital fissure

• Optic canal

• Vidian canal

• Hypoglossal canal

• Pterygopalatine fossa

Page 5: Skull Base

Skull Base Anatomy Review

Page 6: Skull Base

Skull Base Anatomy Review

Foramen spinosumSphenoid spine- lower level

Foramen rotundum- higher level

Pterygopalatine fossa

Foramen ovale

Petro-occipital fissure

Pterygoid canal

f. lacerum

Page 7: Skull Base

*

Skull Base Anatomy Review

Foramen magnum

• Medulla oblongata

• Vertebral arteries

• Anterior/Posterior spinal arteries Hypoglossal canal

• CN XII

• Hypoglossal artery

*

Page 8: Skull Base

Skull Base Anatomy Review

Jugular Foramen

• Pars nervosa: CN IX, inferior petrosal sinus

• Pars vascularis: CN X, XI, jugular bulb

*

* Carotid canal

Page 9: Skull Base

Skull Base Anatomy Review

Foramen Spinosum

• Middle meningeal artery/vein

• CV V3, recurrent branch

• Lesser superficial petrosal nerve

Foramen Ovale

• CN V3

• Lesser petrosal nerve

• Accessory meningeal artery

• Emissary veins

Foramen of Vesalius

• Emissary vein

• Accessory meningeal artery- asc intracranial branch

Page 10: Skull Base

Skull Base Anatomy Review

Foramen Lacerum

• Ascending pharyngeal artery- meningeal branch

• Nerve of pterygoid canal

Vidian Canal

• aka pterygoid canal

• Pterygopalatine fossa - foramen lacerum

• Vidian nerve

• Vidian artery

Page 11: Skull Base

Skull Base Anatomy Review

Foramen rotundum

• CN V2

• Artery of foramen rotundum

• Emissary veins

Page 12: Skull Base

Skull Base Anatomy Review

Pterygopalatine Fossa

• Pterygopalatine ganglia V2

• Pterygopalatine plexus

• Communicates with:

Inferior orbital fissure

Orbital apex

Sphenopalatine foramen

Pterygomaxilary fissure

Foramen rotundum

Vidian canal

Greater/lesser palatine canals and foramina

Page 13: Skull Base

Receives: Superior opthalmic vein Inferior opthalmic vein Sphenoparietal sinus

Drains via: Petrosal sinuses Basilar plexus

Pterygoid plexus

Connection: Circular sinus

Contains: CN III, IV, V1, V2, VI

Skull Base Anatomy Review

Cavernous Sinus

Meckel’s Cave

• Posterior aspect of cavernous sinus

• Gasserian ganglion (sensory root ganglion of CN V)

Page 14: Skull Base

Skull Base Anatomy Review

Superior Orbital Fissure

• CN III, IV, V1, VI

• Middle meningeal artery- orbital branch

• Recurrent meningeal artery

• Superior opthalmic vein

Inferior Orbital Fissure

• Infraorbital artery, vein, and nerve (V2 branch)

Optic Canal

• Optic nerve

• Opthalmic artery

Page 15: Skull Base

Skull Base Anatomy Review

Key Openings

• Foramen spinosum

• Foramen ovale

• Foramen lacerum

• Foramen rotundum

• Foramen magnum

• Foramen of vesalius

• Jugular foramen

• Superior orbital fissure

• Inferior orbital fissure

• Optic canal

• Vidian canal

• Hypoglossal canal

• Pterygopalatine fossa

Page 16: Skull Base

Skull Base Pathology

Chordoma

Chondrosarcoma

Dermoid tumors

Epidermoid tumors

Glomus tumors

Meningioma

Metastases

Myeloma

Neuroma

Schwannoma

Vascular Aneurysm

Page 17: Skull Base

Case 1

Page 18: Skull Base

Chondrosarcoma

CT Findings:

• Irregular, destructive mass

• Centered off midline

• Petro-occipital fissure

• Calcifications, 70%; “rings/arcs”

MRI Findings:

• Low T1 signal, high T2 signal

• Enhance with contrast

• Scalloped, well circumsribed margins

Page 19: Skull Base

Chondrosarcoma

Origin:

• Preexisting cartilaginous lesion, synchondroses, cartilage endplates

Location:

• Paranasal sinuses, skull base, parasellar region

• Long bones, pelvis, sternum, ribs

Clinical:

• 45 yo, median age

• Classic, mesenchymal, or dedifferentiated

Page 20: Skull Base

Case 2

Page 21: Skull Base

CT/MRI Findings:

• Expansile lytic lesion, midline

• Well delineated mass arising from bone

• Large soft tissue component

• Variable calcification

• Anteroposterior extension

• Heterogeneous enhancement on T1, T2

• Dark on T1, bright on T2

Chordoma

DDx:

• Chondroma

• Chondrosarcoma

• Clivus meningioma

Page 22: Skull Base

Chordoma

Origin

• Notochord remnants

Location

• Clivus 35%

• Sacrum 50%, Vertebral bodies 15%

Clinical

• age 30-70

• Slow growing, locally aggressive

• CN VI- CN deficits

• Mets late

• Tx: surgery, radiation

Page 23: Skull Base

Case 3

Page 24: Skull Base

Glomus Tumor

Glomus jugulare CT/MRI Findings:

• Center: jugular foramen

• Limit: hyoid bone

• Enhance w/ contrast

• Salt and pepper appearance on MRI

• Bone erosion

Page 25: Skull Base

Glomus Tumor

Origin:

• Chemoreceptor cells

Location:

• 10% multiple

• glomus jugulare: jugular bulb

• glomus tympanicum: cochlear promontory;

Clinical:

• Pulsatile tinnitus

• Hearing loss

• arrythmia, BP fluctuation

Page 26: Skull Base

References

Erdem E, et al, “Comprehensive Review of Intracranial Chordoma”, Radiographics 2003; 23: 995-1009.

Grossman, R et al, Neuroradiology: The Requisites, Mosby, Philadelphia, 2003

Peretti P et al, “Chordoma”, www.emedicine.com/Radio/topic169.htm, 2005.

Pluta R et al, “Glomus Tumors”, www.emedicine.com/med/topic2994.htm, 2006.

Small J et al, “Chondrosarcoma”, http://brighamrad.harvard.edu/education/online/tcd/tcd.html.

Weissleder, R et al, Primer of Diagnostic Imaging, Mosby, Philadelphia, 2003

http://www.med.wayne.edu/diagRadiology/Anatomy_Modules/axialpages/Home_Page.html

Page 27: Skull Base

Jennings Pond, Chester, CT