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
- Section 6 Primarily Intra-Axial Masses
- 152 Acute Infarction
- 153 Glioblastoma Multiforme
- 154 Therapy-Induced Cerebral Necrosis (Radiation Necrosis)
- 155 Non-Hemorrhagic Metastases
- 156 Cerebral Abscess
- 157 Cerebral Toxoplasmosis
- 158 Primary CNS Lymphoma
- 159 Tumefactive Demyelinating Lesion
- 160 Tuberculoma
- 161 Oligodendroglioma
- 162 Low-Grade Diffuse Astrocytoma
- 163 Gliomatosis Cerebri
- 164 Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-Like Episodes (MELAS)
- 165 Pleomorphic Xanthoastrocytoma (PXA)
- 166 Ganglioglioma
- 167 Neurocysticercosis – Parenchymal
- 168 Dilated Perivascular Spaces
- 169 Neuroepithelial Cyst
- 170 Subependymal Giant Cell Astrocytoma (SEGA)
- 171 Subependymoma
- 172 Ependymoma
- 173 Pilocytic Astrocytoma
- 174 Medulloblastoma
- 175 Hemangioblastoma
- 176 Lhermitte–Duclos (Cowden Syndrome)
- 177 Hypertensive Hematoma
- 178 Amyloid Hemorrhage – Cerebral Amyloid Angiopathy
- 179 Cortical Contusion
- 180 Hemorrhagic Neoplasms
- 181 Hemorrhagic Venous Thrombosis
- 182 Arteriovenous Malformation
- 183 Cavernous Angioma (Cavernoma)
- Section 7 Intracranial Calcifications
- Index
- References
174 - Medulloblastoma
from Section 6 - Primarily Intra-Axial Masses
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
- Section 6 Primarily Intra-Axial Masses
- 152 Acute Infarction
- 153 Glioblastoma Multiforme
- 154 Therapy-Induced Cerebral Necrosis (Radiation Necrosis)
- 155 Non-Hemorrhagic Metastases
- 156 Cerebral Abscess
- 157 Cerebral Toxoplasmosis
- 158 Primary CNS Lymphoma
- 159 Tumefactive Demyelinating Lesion
- 160 Tuberculoma
- 161 Oligodendroglioma
- 162 Low-Grade Diffuse Astrocytoma
- 163 Gliomatosis Cerebri
- 164 Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-Like Episodes (MELAS)
- 165 Pleomorphic Xanthoastrocytoma (PXA)
- 166 Ganglioglioma
- 167 Neurocysticercosis – Parenchymal
- 168 Dilated Perivascular Spaces
- 169 Neuroepithelial Cyst
- 170 Subependymal Giant Cell Astrocytoma (SEGA)
- 171 Subependymoma
- 172 Ependymoma
- 173 Pilocytic Astrocytoma
- 174 Medulloblastoma
- 175 Hemangioblastoma
- 176 Lhermitte–Duclos (Cowden Syndrome)
- 177 Hypertensive Hematoma
- 178 Amyloid Hemorrhage – Cerebral Amyloid Angiopathy
- 179 Cortical Contusion
- 180 Hemorrhagic Neoplasms
- 181 Hemorrhagic Venous Thrombosis
- 182 Arteriovenous Malformation
- 183 Cavernous Angioma (Cavernoma)
- Section 7 Intracranial Calcifications
- Index
- References
Summary
Specific Imaging Findings
Medulloblastomas typically arise in the midline of the posterior fossa, but may occur more laterally and sometimes extend through the fourth ventricle foramina. They are characteristically hyperdense on CT and with very low signal on ADC maps, typically darker than the normal brain. Cystic components are present in a majority of cases and the tumors are hypo- to iso-intense on T1WI. The appearance on post-contrast images is variable, ranging from marked and solid to only subtle marginal or linear enhancement. Calcification and hemorrhage may occasionally be observed, while surrounding edema is rarely prominent. Medulloblastomas have a high rate of early leptomeningeal disease and drop metastases, requiring MR imaging of the entire neural axis (head and spine). There are notable differences between the classic medulloblastoma (CMB) and some of the recently defined variants. CMB is T2 hyperintense, whereas desmoplastic/nodular (DMB) and medulloblastoma with extensive nodularity (MB-EN) are usually isointense; these two variants are also frequently located off-midline. MB-EN may show a characteristic gyriform pattern. In contrast to CMB, all medulloblastoma variants show marked contrast enhancement.
Pertinent Clinical Information
Patients with medulloblastoma are typically children, and increased intracranial pressure is responsible for common presentation with nausea, vomiting, and hydrocephalus. Due to the propensity for early leptomeningeal spread, the initial presentation may also be caused by metastatic disease, such as seizures or spinal cord compression. Extra-CNS spread may rarely occur, usually to the bone.
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- Information
- Brain Imaging with MRI and CTAn Image Pattern Approach, pp. 359 - 360Publisher: Cambridge University PressPrint publication year: 2012