NAVIGATING THE SELLA AND CENTRAL SKULL BASE Christopher P. Hess, M.D., Ph.D. DISCLOSURES Research Support, General Electric SLIDES: http://www.radiology.ucsf.edu/research/meetings/rsna LEARNING OBJECTIVES WE WILL NOT DISCUSS Review general anatomy of the central skull base Develop a structured approach to diagnosis for lesions in & around the central skull base Recognize findings that require urgent intervention X SATCHMO Juxtasellar lesions Exhaustive differentials Skull base foramina in detail MESSAGE CSB: Birdseye View 3 important steps for correct diagnosis in & around the central skull base: Identify lesion origin Recognize key imaging features Evaluate surrounding tissues
CSB: Birdseye View Optic canal Carotid sulcus F. rotundum F. ovale CSB: Birdseye View Frontal Bone Sphenoid Bone F. spinosum Temporal bone Occipital Bone CSB: Birdseye View CSB: Birdseye View LSW LSW GSW Sella GSW Temporal bone Clivus Petro-clival fissure Temporal bone Clivus CSB: Midline Anatomy Planum sphenoidale S SS Nasal cavity CSB NP STOPS AROUND THE CSB 1 1. Planum sphenoidale 2 2. Sella 3. Clivus 3 4. Nasopharynx 4. Sphenoid sinus
STOPS AROUND THE CSB #1 - Planum CASE 1 Progressively worsening visual acuity + CASE 1 Progressively worsening visual acuity CASE 1 A. Macroadenoma B. Meningioma C. Metastatic disease D. Optic nerve glioma + E. Normal variant CASE 1 Skull Base Mengioma A. Macroadenoma Olfactory Groove Planum Sphenoidale Tuberculum Sella Petroclival B. Meningioma C. Metastatic disease D. Optic nerve glioma E. Normal variant
Keys to diagnosis: Sagittal images Separate lesion from pituitary gland Dural tails Skull Base Mengioma Curious Features of Meningiomas Vessel Narrowing Bony Reaction Pneumosinus Primary differential is adenoma Stalk effect - hyperprolactinemia Main issue is growth in small spaces May extend through SB foramina STOPS AROUND THE CSB CASE 2 Headache, AMS, Visual Deficits #2 - Sella + CASE 2 Headache, AMS, Visual Deficits CASE 2 A. Hemorrhagic adenoma B. Rathke cleft cyst C. Craniopharyngioma D. Meningioma * E. Chordoma
CASE 2 Pituitary Adenoma A. Hemorrhagic adenoma B. Rathke cleft cyst C. Craniopharyngioma Sellar enlargement, growth in 6 directions Checklist - optic chiasm, hemorrhage, cav sinus signal similar to gray matter Larger tumors have more heterogeneous signal D. Meningioma E. Chordoma + Diagnostic Key: Where is the Gland? Pituitary Apoplexy Acute visual deficit Intratumoral hemorrhage Blooming on * Hematocrit levels Hyperdensity on CT + The Four Horsemen of the APOCALYPSE The Four Horsemen of the SELLA Death Famine War Conquest Adenoma Rathke Craniopharyngioma Meningioma
Craniopharyngioma CT Helps to Confirm Calcification + Craniopharyngioma Rathke Cleft Cyst: A Histologic Continuum Mostly suprasellar May enlarge sella Mixed solid & cystic Rule of 9 s: 90% calcify ( eggshell ) 90% cystic 90% enhance 90% suprasellar Incidental or symptomatic Typically midline (arise from pars intermedia) 40% intrasellar, 60% extend suprasellar Natural history is slow growth Intracystic Nodule hypointense No enhancement Two Types of Rathke Cleft Cysts Machine Oil (2/3) vs Simple Serous (1/3) STOPS AROUND THE CSB #3 - Clivus hyperintense variable More frequently symptomatic hypointense bright Fluid approximates CSF
CASE 3 Diplopia, CN6 Palsy CASE 3 Diplopia, CN6 Palsy + CASE 3 Your Diagnosis? CASE 3 Your Diagnosis? A. Metastasis A. Metastasis B. Lymphoma B. Lymphoma C. Pituitary adenoma D. Benign osseous lesion E. Chordoma C. Pituitary adenoma D. Benign osseous lesion E. Chordoma CASE 3 Clival Chordoma Ecchordosis Physaliphora Derive from primitive notocord Spheno-occipital synchondrosis Circumscribed midline tumors Expansile growth Physaliphorous cells = high Honeycomb enhancement
Ecchordosis Physaliphora Chondrosarcoma Benign tumor of notochord remants 2% of autopsies Asymptomatic Does not enhance Clival pedicle sometimes present Recommendation: follow + Usually off midline (petro-clival synchondrosis) Tend to be lower grade tumors Better prognosis than chordoma High signal = cartilage Chondrosarcoma Distinguishing Imaging Features? Chordoma Thumb Osseous Matrix Usually off midline (petro-clival synchondrosis) Tend to be lower grade tumors Better prognosis than chordoma High signal = cartilage Up to 0% have chondroid matrix Sequestrations Chordoma Chondroid matrix Chondrosarcoma Distinguishing Imaging Features? Arrested Pneumatization Chordoma Thumb Higher ADC in Chondrosarcoma* Developmental lesion Nonexpansile Sclerotic margins Curvilinear calcification Intralesional fat ADC 2% higher in chondrosarcoma than chordoma Lowest ADC in poorly differentiated chordoma * Yeom et al, AJNR 2013
Diabetic with Cranial Neuropathy x Weeks Skull Base Osteomyelitis Skull Base Osteomyelitis Skull Base Osteomyelitis Diabetic or immunocompromised Headache & cranial neuropathy Isolated or contiguous spread Otitis media & mastoiditis Petrous apicitis Key to diagnosis: surrounding inflammatory changes + Pseudomonas most common Clival Tumor Mimic Fibrous Dysplasia Tumor mimic on MRI! Expansile but shape preserving Low signal Variable enhancement Key to diagnosis is CT +
STOPS AROUND THE CSB CASE 4 Nasal Congestion, Epistaxis #4 - Nasopharynx + CASE 4 Nasal Congestion, Epistaxis CASE 4 A. JNA B. Lymphoma C. Pituitary adenoma + D. Chordoma E. Meningioma CASE 4 Juvenile Nasopharyngeal Angiofibroma A. JNA B. Lymphoma C. Pituitary adenoma D. Chordoma Benign but aggressive Adolescent males Center within posterior nasal cavity Expansion of the pterygopalatine fossa Highly vascular - flow voids Bone destruction E. Meningioma
Other NP Lesions Involving the CSB Other NP Lesions Involving the CSB Nasophayngeal ca Sinonasal lymphoma Rhabdomyosarcoma Infection Nasophayngeal ca Sinonasal lymphoma Rhabdomyosarcoma Infection STOPS AROUND THE CSB CASE Headaches & Hypopituitarism # - Sphenoid sinus + CASE Headaches & Hypopituitarism CASE Headaches & Hypopituitarism +
CASE CASE A. Chordoma A. Chordoma B. Sphenoid mucocele C. Fungal infection D. ICA pseudoaneurysm E. Macroadenoma B. Sphenoid mucocele C. Fungal infection D. ICA pseudoaneurysm E. Macroadenoma ICA Pseudoaneurysm Multiple Cranial Neuropathies Contained arterial rupture from trauma, radiation, or malignancy Clinical triad: visual changes, epistaxis, history of facial trauma Laminated signal Phase artifact from pulsatile flow Beware of the low mass! + Sphenoid Mucocele SUMMARY Location, location, location One imaging modality is often not enough Useful imaging features - low, effects on bone & surrounding structures, calcification, dural tails, etc + Be on the alert for mimics - is it an aneurysm? Make the diagnosis, then think about management
Thank you! christopher.hess@ucsf.edu http://www.radiology.ucsf.edu/research/meetings/rsna