Author:
Michael Kadoch
|
NECT |
CECT |
MRI - T1 |
MRI - T2 |
MRI - FLAIR |
MRI - Diffusion/ADC |
MRI - Postcontrast T1 |
Gross Pathology |
Histology |
Additional comments |
Pilocytic astrocytoma |
Well-marginated round cystic mass with mural nodule or soft tissue component (s); most frequently seen in cerebellar hemisphere
|
Almost always shows enhancement, which can vary from heterogeneous to homogenous enhancement (of the solid components; no image shown).
|
Solid-portions are usualy iso- or hypo-intense to normal brain tissue
|
Hyperintense compared to normal brain; contents of cyst similar to CSF intensity
|
|
No diffusion restriction (no image shown)
|
Intense enhancement of the solid portions
|
Well-circumscribed, smooth mass usually located in cerebellar hemispheres
|
Classic "biphasic" appearance with a loose glial component (g) with microcysts & EG bodies & a more compact component (p) of bipolar cells
|
Most common pediatric CNS glial neoplasm & most common pediatric cerebellar tumor. Associated with NF1.
|
|
|
|
|
|
|
|
|
|
|
|
Glioblastoma multiforme |
Heterogeneous hypo- or iso-dense mass with central hypodensity from necrosis (no image shown)
|
Strong, usually heterogeneous rim enhancement, often with a shaggy inner margin & a thicker margin on the cortical side of the lesion
|
Iso- or hypo- intense heterogeneous mass
|
Heterogeneous, hyperintense mass with adjacent edema +/- necrosis & hemorrhage
|
Heterogeneous, hyperintense mass (seen here in the posterior left temporal lobe) with a large amount of surrouding T2 hyperintensity suggestive of edema
|
Usually do not display diffusion restriction; hyperintense areas seen on the ADC map here of a left temporal GBM suggest absence of diffusion restriction
|
Thick, irregular enhancement surrounding central necrosis
|
Ill-defined, heterogeneous mass with areas of hemorrhage & necrosis
|
Pleomorphic astrocytes (black arrows) surrounded by regions of necrosis (white arrows) & vascular hyperplasia (arrowheads)
|
Most common of all primary intracranial neoplasms
|
|
|
|
|
|
|
|
|
|
|
|
Lymphoma |
Hyperdense lesion usually located in deep gray matter or periventricular white matter which shows less mass effect than expected given the size of the lesion +/- hemorrhage or necrosis; may be multifocal or irregularly shaped (as in this case, which demonstrates the lesion encasing the right ventricle with surrounding vasogenic edema)
|
Most commonly shows dense homogenous enhancement, but can also display ringlike enhancement or no enhancement
|
Iso- or hypo-intense to surrounding brain
|
Usually iso- to hypo-intense lesions, here seen in the bilateral basal ganglia & thalamus, with extensive adjacent edema
|
|
Image 1 (Diffusion): Frequently shows diffusion restriction
Image 2 (ADC): which is confirmed by ADC mapping on this image
|
Marked enhancement, either homogenous or in a ring-like pattern
|
Single or multiple homogenous circumscribed mass(es) with firm consistency & granular surface
|
Predominately B-cell; see sheets of closely packed cells which surround & cluster around vascular channels
|
Usually in basal ganglia or periventriucular white matter
|
|
|
|
|
|
|
|
|
|
|
|
Mets |
Lesions most frequently at GWM junction; often iso- or hypo-dense to surrounding parenchyma & therefore may not be visualized; hemorrhagic mets (here from malignant melanoma) can be hyperattenuating & more conspicuous
|
Strong enhancement which may be homogenous, nodular, or rim-enhancing; delayed imaging may help bring out more conspicuous mets (a ring-enhancing met is seen here from a renal cell carcinoma primary)
|
Most frequently iso- or hypo-intense lesions at the GWM junction; hyperintensity suggests hemorrhagic metastases or melanoma
|
Variable intensity depending on cellular content of metastasis; multiple hyperintense mets from unknown primary seen here
|
|
Image 1: Variable diffusion characteristics of the non-necrotic components of metastasis (most frequently do not restrict diffusion, as seen on this DWI & corresponding ADC map); necrotic components show suppressed DWI signal & increased ADC values
Image 2: Rim of hyperintensity seen here on DWI shows corresponding high ADC value suggesting T2 shine-through from vasogenic edema
|
Usually intense enhancement
|
Usually well-circumscribed round lesions near GWM junction (no image shown)
|
Displays same histology as primary neoplasm (no image shown)
|
Can arise from malignancies outside the CNS (usually via hematogenous spread) or from spread of primary CNS neoplasms; represent > 50% of all brain tumors
|
|
|
|
|
|
|
|
|
|
|
|
Medulloblastoma |
Hyperdense, well-defined cerebellar mass usually with compression of 4th ventricle (arrowheads), +/- calcifications (10%), +/- heterogeneity from necrosis
|
>90% show enhancement, classically homogenous (no image shown)
|
Hypointense compared to adjacent gray matter
|
Isointense to mildly hyperintense compared to surrounding gray matter
|
|
Mass shows diffusion restriction
|
Intense enhancement
|
Usually round, well-circumsized mass most frequently arising from the floor of the 4th ventricle in the midline cerebellar vermis
|
Four histologic subtypes; most common type displays densely-packed small cells with high nuclear:cytoplasm ratio
|
PNET most frequently arising from midline cerebellar vermis; Peak age <10 years & 2nd most common neoplasm in children; WHO grade IV
|
|
|
|
|
|
|
|
|
|
|
|
Ganglioglioma |
Classically a cystic mass with mural nodule, but often solid of varying density +/- calcifications +/- erosion of adjacent calcarium
|
Variable enhancement pattern (~50% enhance; no image shown)
|
Mass is often iso- to hypo-intense; often cystic with mural nodule (40%)
|
Heterogeneous hyperintense mass or mural nodule without significant surrounding edema
|
|
|
Variable enhancement of mass or mural nodule
|
Well-circumscribed mass, often cystic with mural nodule (image shows bulging of the cortical surface from the tumor)
|
Mixture of neoplastic ganglion cells (arrowheads) & glial cells (often astrocytomas) of varying levels of differentiation
|
80% occur in patients younger than 30 years old. Prediliction for cerebral hemispheres, temporal > frontal > parietal. Low grade (I or II)/well-differentiated. Frequently present with history of seizures.
|
|
|
|
|
|
|
|
|
|
|
|
Dysembryoplastic neuroepithelial tumor |
Frequently wedge-shaped hypodense region in a cortical or subcortical location
|
Usually nonenhancing (no image shown)
|
Sharply-marginated hypointense mass
|
High signal intensity; often multinodular or septated
|
|
|
Mass generally doesn't enhance
|
Lesion near the cortex, often with a gelatinous consistency
|
Neuronal elements surrounded by prominent vacuoles, called "floating neurons" (arrows)
|
Most frequently in temporal lobe & strongly associated with seizures; usually in patients <20
|
|
|
|
|
|
|
|
|
|
|
|
Oligodendroglioma |
Mixed density (hypo- or iso-dense) mass usually arising from cortical or subcortical frontal lobe, +/- calcifications (70%); can cross corpus callosum as in this image
|
Variable enhancement pattern (~50% enhance)
|
Hypo- or iso-intense heterogeneous mass, usually cortical or subcortical
|
Hyperintense mass; heterogeneity due to calcium
|
Heterogeneous, hyperintense mass
|
ADC shows hyperintense signal in the region of the mass, which indicates absence of diffusion restriction
|
~50% enhance, usually heterogeneously; no enhancement seen with this image
|
Solid, well-defined, encapsulated mass which causes expansion of the cortex & gyri
|
Two main subtypes:
Well-differentiated oligodendroglioma, which displays rounded homogenous nuclei with clear cytoplasm
Anaplastic oligodendroglioma, which shows increased cellularity & marked atypia
|
Most commonly in frontal lobe of middle-age adults.
|
|
|
|
|
|
|
|
|
|
|
|
Desmoplastic infantile ganglioglioma |
Heterogeneous cystic (c) & solid (s) mass; solid component usually cortically-based
|
Marked enhancement of solid component of mass (no image shown)
|
Hypointense cyst, often multiloculated, with a heterogeneous solid component often abutting the dura
|
High intensity cystic component with heterogeneous low-intensity solid component
|
|
|
Marked enhancement of solid tumor component
|
Cortically-based solid tumor component with adjacent dural thickening associated with large cystic component
|
Dense desmoplastic tissue (arrow) with mix of glial & neuronal cells (arrowheads)
|
Location: Frontal > Parietal > Temporal. Majority of cases reported in children < 1 year old. Usually present due to rapidly increasing head size.
|
|
|
|
|
|
|
|
|
|
|
|
Pleomorphic xanthoastrocytoma |
Cystic supratentorial mass with a mural nodule which is adjacent to the leptomeninges (can also appear solid or heterogeneous)
|
Strong enhancement of the mural nodule or entire tumor mass
|
Solid portions are iso- or hypo-intense to surrounding gray matter
|
Solid portions are iso- or hyper-intense to surrounding gray matter
|
Cystic portion is iso-intense to CSF (no image shown)
|
|
Strong enhancement of solid portion or mural nodule as well as rim enhancement of the cystic portion; may see enhancement of a dural tail
|
|
Pleomorphic astrocytic cells with intracytoplasmic lipid (xanthomatous change, arrow), usually superficial & attached to the meninges
|
Rare tumors occuring in adolescents or young adults, often with a history of seizures. Suratentorial tumor most commonly in temporal lobes.
|
|
|
|
|
|
|
|
|
|
|
|
Gliomatosis cerebri |
Vague hypodense assymetry involving multiple lobes (no image shown)
|
Usually nonenhancing (no image shown)
|
Iso- or hypo-intense infiltrating mass involving at least 3 lobes (no image shown)
|
Hyperintense infiltrating mass involving at least 3 lobes, with expansion of the involved lobes (here seen involving multiple areas of the bilateral periventricular white matter)
|
Hyperintense, involving multiple lobes
|
|
Usually no or minimal patchy enhancement; this image shows no enhancement of a hypointense lesion in the right frontal centrum semiovale & a patchy enhancing area in the left centrum semiovale
|
Blurring of gray-white junctions, heterogeneous discoloration, +/- distinct tumor nodules
|
Glial cells (most commonly astrocytes) which demonstrate pleomorphism & invasion of parenchyma in a parallel orientation to myelinated tracts
|
Infiltrative tumor involving at least 3 lobes; differentiated from multifocal gliomas by lack of clear distinction from adjacent normal brain tissue, as well as by continuity of the cellular infiltration.
|
|
|
|
|
|
|
|
|
|
|
|
Hemangioblastoma |
Isodense mass moss frequently in posterior fossa +/- hypodense cystic component (no image shown)
|
Intense enhancement of solid components (no image shown)
|
Nodule/solid components are iso- or hypo-intense to brain (seen here in the hypothalamus); cystic components mildly hyperintense to CSF
|
Hyperintense mass in posterior fossa; 60% are cystic with mural nodule, both of which are hyperintense on T2
|
Solid components of tumor are hyperintense, cystic components show same signal intensity as CSF (seen here is hippocampal hemangioblastoma in a patient with vHL)
|
|
Strong enhancement of entire solid tumor or mural nodule of a cystic tumor
|
Vascular, well-circumscribed, unencapsulated mass (no image shown)
|
Proliferation of neoplastic fusiform stromal cells (arrow) with adjacent blood material (arrowheads)
|
Classically cystic mass with mural nodule in the posterior fossa (~60% are actually cystic; ~95% are in the posterior fossa); WHO grade I tumors; Strong association with vHL (often occur supratentorially)
|
|
|
|
|
|
|
|
|
|
|
|