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

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

2. 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

3. Skull Base Anatomy Review Temporal Bone Temporal bone- petrous portion Sphenoid Bone Occipital Bone • Key Fissures • Petrosphenoidal fissure • Petrooccipital fissure • Key Sutures • Sphenosquamous Suture • Occipitomastoid Suture

4. 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

5. Skull Base Anatomy Review

6. Pterygopalatine fossa Pterygoid canal Foramen rotundum- higher level Foramen ovale Sphenoid spine- lower level Petro-occipital fissure Skull Base Anatomy Review f. lacerum Foramen spinosum

7. Skull Base Anatomy Review • Foramen magnum • Medulla oblongata • Vertebral arteries • Anterior/Posterior spinal arteries • Hypoglossal canal • CN XII • Hypoglossal artery * *

8. Skull Base Anatomy Review • Jugular Foramen • Pars nervosa: CN IX, inferior petrosal sinus • Pars vascularis: CN X, XI, jugular bulb * * Carotid canal

9. Foramen Ovale • CN V3 • Lesser petrosal nerve • Accessory meningeal artery • Emissary veins • Foramen of Vesalius • Emissary vein • Accessory meningeal artery- asc intracranial branch Skull Base Anatomy Review • Foramen Spinosum • Middle meningeal artery/vein • CV V3, recurrent branch • Lesser superficial petrosal nerve

10. 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

11. Skull Base Anatomy Review • Foramen rotundum • CN V2 • Artery of foramen rotundum • Emissary veins

12. 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

13. Skull Base Anatomy Review Cavernous Sinus 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 • Meckel’s Cave • Posterior aspect of cavernous sinus • Gasserian ganglion (sensory root ganglion of CN V)

14. Inferior Orbital Fissure • Infraorbital artery, vein, and nerve (V2 branch) • Optic Canal • Optic nerve • Opthalmic artery Skull Base Anatomy Review • Superior Orbital Fissure • CN III, IV, V1, VI • Middle meningeal artery- orbital branch • Recurrent meningeal artery • Superior opthalmic vein

15. 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

16. Skull Base Pathology Meningioma Metastases Myeloma Neuroma Schwannoma Vascular Aneurysm Chordoma Chondrosarcoma Dermoid tumors Epidermoid tumors Glomus tumors

17. Case 1

18. 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

19. 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

20. Case 2

21. Chordoma • 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 • DDx: • Chondroma • Chondrosarcoma • Clivus meningioma

22. 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

23. Case 3

24. Glomus Tumor • Glomus jugulare CT/MRI Findings: • Center: jugular foramen • Limit: hyoid bone • Enhance w/ contrast • Salt and pepper appearance on MRI • Bone erosion

25. Glomus Tumor • Origin: • Chemoreceptor cells • Location: • 10% multiple • glomus jugulare: jugular bulb • glomus tympanicum: cochlear promontory; • Clinical: • Pulsatile tinnitus • Hearing loss • arrythmia, BP fluctuation

26. 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

27. Jennings Pond, Chester, CT