Book contents
- Frontmatter
- Contents
- List of contributors
- List of abbreviations
- Preface
- Section 1 Bilateral Predominantly Symmetric Abnormalities
- Section 2 Sellar, Perisellar and Midline Lesions
- Section 3 Parenchymal Defects or Abnormal Volume
- Section 4 Abnormalities Without Significant Mass Effect
- Section 5 Primarily Extra-Axial Focal Space-Occupying Lesions
- 130 Arachnoid Granulations
- 131 Leptomeningeal Cyst
- 132 Epidural Hematoma
- 133 Subdural Hematoma
- 134 Empyema
- 135 Secondary (Systemic) Lymphoma
- 136 Idiopathic Hypertrophic Pachymeningitis
- 137 Olfactory Neuroblastoma
- 138 Meningioma
- 139 Desmoplastic Infantile Ganglioglioma
- 140 Hemangiopericytoma
- 141 Schwannoma
- 142 Arachnoid Cyst
- 143 Epidermoid
- 144 Aneurysm
- 145 Racemose Neurocysticercosis
- 146 Ependymal Cyst
- 147 Choroid Plexus Cyst
- 148 Choroid Plexus Papilloma
- 149 Intraventricular Meningioma
- 150 Central Neurocytoma
- 151 Ventricular Diverticula
- Section 6 Primarily Intra-Axial Masses
- Section 7 Intracranial Calcifications
- Index
- References
141 - Schwannoma
from Section 5 - Primarily Extra-Axial Focal Space-Occupying Lesions
Published online by Cambridge University Press: 05 August 2013
- Frontmatter
- Contents
- List of contributors
- List of abbreviations
- Preface
- Section 1 Bilateral Predominantly Symmetric Abnormalities
- Section 2 Sellar, Perisellar and Midline Lesions
- Section 3 Parenchymal Defects or Abnormal Volume
- Section 4 Abnormalities Without Significant Mass Effect
- Section 5 Primarily Extra-Axial Focal Space-Occupying Lesions
- 130 Arachnoid Granulations
- 131 Leptomeningeal Cyst
- 132 Epidural Hematoma
- 133 Subdural Hematoma
- 134 Empyema
- 135 Secondary (Systemic) Lymphoma
- 136 Idiopathic Hypertrophic Pachymeningitis
- 137 Olfactory Neuroblastoma
- 138 Meningioma
- 139 Desmoplastic Infantile Ganglioglioma
- 140 Hemangiopericytoma
- 141 Schwannoma
- 142 Arachnoid Cyst
- 143 Epidermoid
- 144 Aneurysm
- 145 Racemose Neurocysticercosis
- 146 Ependymal Cyst
- 147 Choroid Plexus Cyst
- 148 Choroid Plexus Papilloma
- 149 Intraventricular Meningioma
- 150 Central Neurocytoma
- 151 Ventricular Diverticula
- Section 6 Primarily Intra-Axial Masses
- Section 7 Intracranial Calcifications
- Index
- References
Summary
Specific Imaging Findings
Cranial nerve (CN) schwannoma (neuroma, neurinoma, Schwann cell tumor, neurolemmoma, neurilemmoma) is typically welldelineated, hypodense on CT and T1 hypointense to isointense to the pons on pre-contrast images and with avid post-contrast enhancement. Schwannomas can arise along any cranial nerve,most commonly the vestibular nerve in the internal auditory canal (IAC), followed by the trigeminal nerve (including Meckel's cave), facial nerve, glossopharyngeal, vagus, and spinal accessory nerve. Schwannomas involving oculomotor, trochlear, abducens, and hypoglossal nerves are rare. Enhancement may be homogenous or heterogenous, based on the absence or presence of necrosis and/or intramural cysts. Calcifications are not present. Smaller tumors are usually round, ovoid-shaped or less frequently poly-lobular, T2 iso- to hypointense. Larger tumors are typically of high T2 signal and heterogenous with internal cystic areas. Schwannomas exhibit increased diffusion and are hyperintense on ADC maps. Eighty-five percent of vestibular schwannomas are centered at the IAC meatus. Larger tumors show the typical “ice creamon cone” appearance and usually lead to smooth widening of the internal auditory canal. Arachnoid cysts/trapped CSF are found around the tumor in a minority of cases, while increased signal within the ipsilateral inner ear structures is frequently present on FLAIR images.
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- Brain Imaging with MRI and CTAn Image Pattern Approach, pp. 291 - 292Publisher: Cambridge University PressPrint publication year: 2012