Neurosurgical Atlas Flashcards
1
Q
Basic description of pilocytic astrocytomas.
A
- Slow growing, well circumscribed tumor arising from astrocytic precursors.
- Most common pediatric primary intracranial neoplasm.
2
Q
Pathology of pilocytic astrocytomas.
A
- Biphasic pattern of astrocytes (Rosenthal fibers and multipolar cells).
- Syndromic or sporadic (optic nerve/chiasm PAs associated with NF1).
3
Q
CT findings of pilocytic astrocytomas.
A
- Mixed solid-cystic mass with minimal surrounding edema.
- May have calcification.
- Strong mural nodular enhancement, non-enhancing cystic component.
4
Q
T1WC+C findings of pilocytic astrocytomas.
A
- Enhancing solid component with/without cyst wall enhancement.
5
Q
Basic description of pleomorphic xanthoastrocytoma.
A
- Supratentorial cortical/peripheral astrocytic tumor.
6
Q
Pathology of pleomorphic xanthoastrocytoma.
A
- Astrocyte pleomorphism and lipid-containing cells.
2. May show anaplastic features (10-15%).
7
Q
General imaging features of pleomorphic xanthoastroctyoma.
A
- Temporal lobe > frontoparietal > occipital.
- Classically cystic with solid mural nodule, often abuts pial surface.
- May have enhancing dural tail of leptomeningeal attachment.
8
Q
CT findings of pleomorphic xanthoastrocytoma.
A
- Hypodense cystic component.
2. Minimal to moderate adjacent edema.
9
Q
T1WC + C findings of pleomorphic xanthoastrocytoma.
A
- Generally strong enhancement, sometimes enhancing dural tail/leptomeninges.
10
Q
Basic description of anaplastic astrocytoma.
A
Infiltrating malignant astrocytoma with ill-defined tumor margins and extensive edema.
11
Q
Pathology of anaplastic astrocytoma.
A
- Usually develops from malignant degeneration of low-grade astrocytoma.
- Commonly dedifferentiates into GMB (-50%) within 2 years.
- Focal or diffuse anaplasia, highly proliferative.
- Increased cellularity and nuclear atypia, usually no necrosis or microvascular proliferation.
12
Q
General imaging characteristics of anaplastic astrocytoma.
A
- Ill-defined, infiltrating white matter mass.
- Location in frontal and temporal lobes most common, brainstem and spinal cord uncommon.
- Spreads along white matter tracts, but may spread via CSF, leptomeninges, and ependymal.
13
Q
CT findings of anaplastic astrocytoma.
A
- Hypodense, ill-defined white matter mass.
2. Usually does not enhance on contrast-enhanced CT.
14
Q
Basic description of GBM.
A
- Malignant, rapidly enlarging astrocytic tumor with microvascular proliferation and necrosis.
- Most common primary intracranial neoplasm.
15
Q
Pathology of GBM.
A
- Necrosis and microvascular proliferation are characteristic features.
- Develops do novo (primary) or from malignant dedifferentiation of AA (secondary).
- Associated with NF-1, Turcot, Li-Fraumeni, and Maffuci syndromes.
16
Q
Clinical features of GBM.
A
- Median survival < 1 year (better prognosis with younger age, greater resection, and MGMT-positive genetics).
17
Q
CT features of GBM.
A
- Irregular hypo-to isodense mass with central hypodensity (necrosis).
- Surrounding vasogenic edema.
- Irregular, heterogenous ring of enhancement on contrast-enhanced CT.
18
Q
T1WI of GBM.
A
- Irregular, hypointense white matter mass, areas of hyperintensity may represent subacute hemorrhage.
19
Q
T2WI of GBM.
A
- Heterogeneously hyperintense, surrounding vasogenic edema, presence of flow voids suggests neovasculatiry.
20
Q
T1WI+C of GBM.
A
- Thick, irregular ring of peripheral enhancement.
2. Enhancement may be ring, nodular, homogenous or patchy.
21
Q
MRS of GBM.
A
- Decreased NAA and myoinositol.
- Increased choline, lipid/lactate peak indicating anaerobic metabolism of necrosis.
- Increased relative CBV compared with lower grade astrocytomas.
22
Q
Pathology of posterior fossa ependymoma.
A
- 3 histological subtypes (PF-ependymoma, PF-ependymoma type A, PF ependymoma type B).
- Subtype A highly malignant.
23
Q
General imaging features of posterior fossa ependymoma.
A
- Well-marginated, lobulated mass.
- Majority arise within 4th ventricle and extend through/widen ventricular foramina into adjacent parenchymal and basal cisterns.
- Displaces rather than invades adjacent parenchyma.
24
Q
CT of posterior fossa ependymoma.
A
- Lobulated, often calcified mass arising within inferior portion of 4th ventricle.
25
T1WI of posterior fossa ependymoma.
1. Heterogeneous, often hypointense, areas of calcification and hemorrhage appear hyperintense.
26
T1WI+C of posterior fossa ependymoma.
1. Variable enhancement.
27
MRS of posterior fossa ependymoma.
1. Elevated choline and lactate.
2. Decreased NAA.
3. MRS not generally helpful in distinguishing between posterior fossa medulloblastomas and astrocytomas.
28
Basic description of supratentorial ependymomas.
1. Hemispheric glial-cell tumor arising from ependymal cells.
2. Extraventricular subependymomas may arise from fetal ependymal rests.
29
Pathology of supratentorial ependymomas.
1. WHO I: myxopapillary ependymoma (more often occurring at the conus medulluaris).
2. WHO II: cellular, papillary, clear cell, and tanycytic variants.
3. WHO III: most common in adults, trisomy 19 and anaplastic variants.
30
Histology of supratentorial ependymomas.
1. Perivascular and ependymal rosettes.
31
Imaging features of supratentorial ependymomas.
1. Heterogeneous, mixed solid-cystic supratentorial mass.
2. Often large at presentation (>4cm).
3. Majority are extraventricular.
4. 3rd ventricle most common intraventricular location.
32
CT imaging of supratentorial ependymomas.
1. Heterogeneously iso-to hypodense.
| 2. Calcification common.
33
T2*/GRE/SWI of supratentorial ependymomas.
1. Black signal blooming secondary to calcification and/or hemosiderin deposition from blood products.
34
Pathology of oligodendrogliomas.
1. Arises from malignant transformation of mature oligodendrocytes or glial precursor cells.
2. Calcification and cystic degeneration common.
3. "Fried egg" appearance due to rounded nuclei and clear cytoplasm.
4. Associated with IDH1 or MGMT positive genetics.
35
General imaging features of oligodendrogliomas.
1. Usually supratentorial location (frontal lobe >> temporal, parietal, and occipital lobes).
2. Calcification present in 40-80%.
3. Usually minimal to no peritumoral edema.
36
MRS of oligodendrogliomas.
1. elevated choline, decreased NAA, absent lipid/lactate peak (unlike anaplastic oligodendroglioma).
2. Unique characteristic of elevated relative CBV in spite of lower grade due to pathologic feature of "chicken-wire vascularity".
37
Pathology of atypical/malignant meningiomas.
1. WHO grade II (atypical) and WHO grade III (malignant).
2. Most likely arise from dedifferentiation of traditional meningiomas.
3. Increased mitoses, nucleus-to-cytoplasm ratio, necrosis, and nuclear atypia compared to traditional meningioma's.
38
General imaging features of atypical/malignant meningiomas.
1. Dural based, extra-axial mass with necrosis, invasion of adjacent brain, and extensive peritumoral brain edema.
2. May arise within any location in the neuraxis. (AMs: CPA cistern, tentorium most common; MM: parasagittal or cerebral convexity).
39
CT findings of atypical/malignant meningiomas.
1. Ill-defined, hyperdense mass extending intra-and extra cranially.
2. Minimal calcification compared to traditional meningiomas.
3. Extensive hypodense peritumoral edema.
4. Avid enhancement on contrast-enhanced CT.
40
FLAIR imaging of atypical/malignant meningiomas.
1. often marked hyperintense peritumoral edema.
41
T1WI+C of atypical/malignant meningiomas.
1. Avid enhancement with enhancing margins invading adjacent structures.
42
DWI of atypical/malignant meningiomas.
1. Reduced diffusivity (bright DWI, dark ADC).
43
Basic description of craniopharyngiomas.
1. Benign tumor arising from Rathke pouch epithelium.
| 2. Most common pediatric nonglial-origin tumor.
44
Pathology of craniopharyngiomas.
1. Two histological types (adamantinomatous - partially cystic mass in children, papillary - solid mass in adults).
2. Cysts with viscous "crankcase oil" or "motor oil" contents.
45
Age distribution of craniopharyngiomas.
1. Adamantinomatous - ages 5-15 years.
| 2. Papillary - > 50 years.
46
General imaging features of craniopharyngiomas.
1. Multilobulated or multicystic mass.
2. Location may be suprasellar, supra and intrasella, or completely intrasellar.
3. Adamantinomatous - mixed solid-cystic or predominantly cystic.
4. Papillary - predominantly solid.
47
CT of adamantinomatous craniopharyngiomas.
1. Cystic components are hypodense, solid components are isodense.
2. 90% with calcifications.
3. 90% enhance (nodule or rim enhancement).
48
CT of papillary craniopharyngiomas.
1. Isodense solid tumor.
| 2. Calcification much more rate.
49
T1WI of craniopharyngiomas.
1. Often hyperintense due to proteinaceous material.
| 2. Isointense or heterogenous solid tumor component.
50
T1WI+C of craniopharyngiomas.
1. Enhancement of cyst wall and solid tumor components.
51
Basic description of vestibular schwannomas.
1. Benign peripheral nerve sheath tumor arising from Schwann cells of CN 8 (vestibular portion) within the CPA-IAC.
52
Pathology of vestibular schwannomas.
1. CN 8 superior vestibular branch > inferior branch.
| 2. Variable hpercellular (Antoni A) and more hypocellular (Antoni B) areas are characteristic.
53
General imaging features of vestibular schwannomas.
1. Well-marginated, enhancing mass within the CPA or CPA-IAC with "ice cream on cone" morphology.
2. Expansion of the IAC (in contrast to meningiomas).
3. Calcification, cystic degeneration may be seen.
54
T2WI of vestibular schwannomas.
1. High resolution sequences (SPACE, CISS, or FIESTA) optimize visualization.
2. Appears as a hypo-to isointense CPA-IAC filling defect.
55
Basic description of pineocytomas.
1. Slow-growing pineal parenchymal tumor.
56
Pathology of pineocytomas.
1. Arises from pineocytes or pineocyte precursors.
2. Well-differentiated tumor without mitoses or necrosis.
3. Small, uniform cells arranged in sheets with intervening septae are typical microscopic features.
57
General features of pineocytomas.
1. Peripherall-calcified, well circumscribed pineal region mass.
2. Calcifications and cysts are often present.
3. Rare intraventricular extension, CSF dissemination or parenchymal invasion.
58
CT findings of pineocytomas.
1. Well-circumscribed, iso to hypodense pineal mass.
| 2. +/- peripheral calcification.
59
Basic description of pineoblastomas.
1. Malignant, invasive pineal parenchymal tumor arising from embyronic pineocyte precursors (PNET).
60
Pathology of pineoblastomas.
1. Invades adjacent structures often including the cerebral aqueduct.
2. CSF dissemination common.
3. Hypercellularity and increased mitoses are characteristic features.
4. Associated with germline DICER1 mutations (DICER! syndrome) and RB1 (bilateral retinoblastomas and pineoblastoma).
61
General imaging features of pineoblastoma.
1. Lobulated, poorly marginated pineal mass.
2. Often larger and more invasive than pineocytomas.
3. Peripheral ("exploded") calcifications common.
4. Commonly invades adjacent structures including cerebral aqueduct, corpus callosum, thalamus, brainstem and vermis.
5. May see superior displacement of cerebral veins and mass effect on the tectum.
62
CT findings of pineoblastoma.
1. Heterogenous density, irregular pineal mass.
| 2. Peripheral calcification.
63
T1WI+C of pineoblastoma.
1. Heterogenous enhancement.
64
MRS of pineoblastoma.
1. Elevated choline.
| 2. Decreased NAA.
65
Basic description of germinoma.
1. Intracranial germ cell tumor often occurring in the pineal region.
66
Pathology of germinoma.
1. WHO grade II(pure germinoma) or grade III (syncytiophoblastic giant cells).
2. Associated with Down's, Klinefelter, and NF-1 syndromes.
3. Polygonal primitive germ cells and lymphocytic infiltrates are common microscopic features.
67
Gender predilection for germinomas.
1. Marked male gender predilection in pineal region germinomas.
2. Females more commonly afflicted with suprasellar germinomas.
68
Lab findings for germinomas.
1. Increased serum/CSF B-hcg.
69
CT findings for germinomas.
1. Lobulated, hyperdense mass.
2. +/- cysts, hemorrhage.
3. Avid, homogeneous enhancement on contrast enhanced CT +/- CSF dissemination.
70
T1WI of germinomas.
1. Iso to hyperintense.
| 2. Normal posterior pituitary "bright spot" may be absent in suprasellar germinoma.
71
DWI of germinomas.
1. Diffusion restriction due to hypercellularity.
72
T1WI+C of germinomas.
1. Avid, homogeneous enhancement including areas of CSF dissemination and parenchymal invasion.
73
MRS of germinomas.
1. Elevated choline.
| 2. Decreased NAA.
74
Basic description of teratomas.
1. Midline intracranial tumor arising from mulitpotential germ cells.
75
Pathology of teratomas.
1. Contains tissue from all germ cell types: ecto, meso and endoderm.
2. Three types:
Mature - well differentiated, WHO grade 1, often with cystic tumor component.
Immature - intermediate differentiation.
Malignant - malignant degeneration of immature teratoma, may contain somatic tumors.
76
Clinical features of teratomas.
1. Arises during fetal development due to aberrant formation of the primitive streak.
2. Mean patient age at diagnosis is 15 years.
3. Majority are lethal in utero or during 1st week of life.
77
Lab findings for teratomas.
1. Increased serum CEA +/- alpha fetoprotein.
78
CT findings of teratomas.
1. Heterogeneous and containing very low density fat, hyperdense calcification, intermediate density soft tissue, and low-density cysts.
79
T1WI of teratomas.
1. Heterogeneous hyperintensity due to fatty components and calcification.
80
Basic description of arachnoid cysts.
1. Intracranial, extra-axial, CSF containing cysts without communication with the ventricular system.
81
Pathology of arachnoid cysts.
1. Originates from embryonic meninges that fail to fuse during Sylvian fissure development.
2. CSF contents may arise from unidirectional inflow (ball-valve mechanism) vs secretion by cells lining AC wall.
3. Rare association with Aicardi and Pallister-Hall syndromes.
4. Associated with temporal lobe hypoplasia, subdural hematomas, foramen of Monro/aqueductal stenosis.
82
General imaging features of arachnoid cysts.
1. Well-marginated extra-axial cyst which follows CSF density/signal intensity.
2. Mass effect and displacement of adjacent cortex.
83
Common locations for arachnoid cysts.
1. Middle cranial fossa >> CPA, suprasellar cisterns.
84
DWI of arachnoid cysts.
1. No diffusion restriction.
85
Basic description of AT/RTs.
1. Aggressive, infiltrative pediatric rhabdoid tumor with highly variable appearance and histology.
86
Pathology of AT/RTs.
1. WHO grade IV.
2. Involves mesenchymal, neuronal, glial, and epithelial cell lines ("teratoid").
3. Mutations of SMARCB1/hSNF5 and loss of INI1 protein is diagnostic of AT/RT.
87
Clinical features of AT/RTs.
1. Most commonly affects children < 3 years and usually in the posterior fossa.
2. No gender predilection.
3. Treatment involves resection +/- adjuvant chemoradiation.
4. Overall 5-year survival < 30%.
88
General imaging features of AT/RTs.
1. Highly variable, nonspecific morphology and imaging characteristics.
2. Mixed solid-cystic mass.
3. +/- calcification, hemorrhage, and necrosis.
4. Leptomeningeal/CSF dissemination common (>30%).
89
CT findings of AT/RTs.
1. Hyperdense mass.
| 2. Hyperdense calcification and hemorrhage or hypodense cysts may be seen.
90
MRI findings of AT/RTs.
1. Heterogenous signals due to cystic or hemorrhagic components.
91
DWI for AT/RTs.
1. Demonstrates restricted diffusion in hypercellulr regions of tumor.
92
MRS of AT/RTs.
1. Elevated choline.
2. Decreased NAA.
3. +/- lactate/lipid peaks.
93
Basic description of carotid body glomus tumor (carotid body paraganglioma).
1. Benign, hypervascular neuroendocrine tumor of neural crest origin.
94
Pathology of carotid body glomus tumor (carotid body paraganglioma).
1. Glomus caroticum arise from glomus bodies within the carotid body at the carotid bifurcation.
2. Composed of chemoreceptor cells of neural crest origin.
3. Arterial supply from ascending pharyngeal.
4. Associated with NF-1, MEN-2, and VHL.
5. Chief cells rests (zellballen) and sustentacular cells within fibromuscular stroma are characteristic microscopic features.
95
Clinical features of carotid body glomus tumor (carotid body paraganglioma).
1. Pulsatile, painless mass at the angle of the mandible with gradual enlargement.
2. CN X and XII neuropathies.
96
Treatment of carotid body glomus tumor (carotid body paraganglioma).
1. Surgical resection based on Shamblin classification: tumor size and degree of contact with ICA.
2. Higher classification predicts surgical morbidity (CN neuropathy).
97
General imaging features of carotid body glomus tumor (carotid body paraganglioma).
1. Lobulated, enhancing mass centered within the carotid bifurcation.
98
Basic description of central neurocytoma.
1. Well-marginated, usually benign intraventricular neuroepithelial tumor.
99
Pathology of central neurocytoma.
1. WHO grade II.
2. Round cells with stippled nuclei are characteristic microscopic features.
3. Synaptophysin positive.
100
General imaging findings of central neurocytoma.
1. Supratentorial, intraventricular mass with cystic or bubbly appearance.
2. Often located with lateral ventral frontal horn or body near the foramen of Monro.
3. Frequently shows calcification.
101
CT findings of central neurocytoma.
1. Heterogeneous density intraventricular mass due to solid and cystic components.
102
T1WI+C of central neurocytoma.
1. Heterogenous enhancement.
103
MRS of central neurocytoma.
1. Increased choline.
2. Decreased NAA.
3. Glycine peak at 3.55.
104
Basic description of choroid plexus carcinoma.
1. Malignant, rapidly growing intraventricular tumor arising from choroid plexus epithelium.
105
Pathology of choroid plexus carcinoma.
1. Hypercellularity, pleomorphism, and increased mitosis are characteristic microscopic features.
2. Increased Ki-67 index.
3. Hemorrhage, cysts, calcification and necrosis are common.
4. Invasion of adjacent ependyma.
5. High association with SV40 virus.
6. Associated with Li-Fraumeni and Aicardi syndromes.
106
General imaging features of choroid plexus carcinoma.
1. lobulated or irregular, enhancing intraventricular mass with ependymal invasion.
2. Lateral ventricle was complication.
107
CT findings for choroid plexus carcinoma.
1. Iso to hyperdense.
| 2. +/- Calcification.
108
FLAIR imaging of choroid plexus carcinoma.
1. Heterogeneous signal intensity, periventricular bright signal suggests invasion and/or transependymal CSF flow from hydrocephalus.
109
MRS of choroid plexus carcinoma.
1. Elevated choline.
2. Elevated lactate.
3. Absent NAA.
110
Basic description of choroid plexus papilloma.
1. Benign, lobulated, intraventricular mass arising from choroid plexus epithelium.
2. Made disseminate via CSF.
111
Pathology of choroid plexus papilloma.
1. Fibrovascular connective tissue covered by cuboidal or columnar choroid plexus epithelium.
2. WHO grade 1 (typical CPP) or II (atypical CPP).
3. Cysts and hemorrhage may be seen.
4. Rare necrosis or invasion of adjacent brain parenchyma.
5. Associated with Li-Fraumeni and Aicardi syndromes.
6. Associated with SV40 infection.
112
Clinical features of choroid plexus papilloma.
1. Usually arising in lateral or 4th ventricles.
2. Lateral ventricle: majority of cases < 20 years old.
3. 4th ventricle: adults more commonly affected.
113
General imaging features of choroid plexus papilloma.
1. Lobulated, frond-like, and avidly enhancing intraventricular mass.
2. Arising in regions of choroid plexus.
3. Lateral ventricle atrium or trigone > foramen of Luschka or posterior medullary velum of 4th ventricle > 3rd ventricular roof.
4. Hemorrhage and calcification common.
114
T1WI+C findings of choroid plexus papilloma.
1. Avid, homogenous enhancement most common.
115
Basic description of colloid cysts.
1. Mucin-containing, unilocular third ventricular cyst often located near the foramen of Monro.
2. Synonymous terms: paraphyseal or neuroendodermal cyst.
116
Pathology of colloid cysts.
1. Congenital abnormality due to ependymal encystment or persistence of the paraphysis.
2. Thin fibrous capsule of simple or pseudostratified epithelium with goblet and ciliated cells.
3. Center filled with mucin, cholesterol, and desquamated epithelium.
117
General imaging features of colloid cysts.
1. Well-marginated hyperdense unilocular cyst arising within anterior third ventricle near the foramen on Monro.
2. Forniceal pillars elevated over cyst.
118
CT findings of colloid cysts.
1. Majority are hyperdense due to high proteinaceous content.
119
T1WI of colloid cysts.
1. Iso to hyperintense due to cholesterol content.
120
T1WI + C of colloid cysts.
1. No enhancement.
121
Basic description of dysplastic cerebellar gangliocytoma.
1. AKA Lhermitte-Duclos, the neurologic manifestation of multiple hamartoma and neoplasia syndrome or Cowden syndrome.
2. Benign cerebellar lesion of uncertain etiology.
122
Pathology of dysplastic cerebellar gangliocytoma.
1. Benign cerebellar mass with thickened, irregular cerebellar folia.
2. Pathogenesis unclear: hamartomatous, neoplastic, or congenital.
3. WHO grade I.
4. No malignant potential.
123
Microscopic features of dysplastic cerebellar gangliocytoma.
1. Absence of cerebellar Purkinje cells, abnormal ganglion cells, and hypertrophic granule cell layer.
124
General imaging features of dysplastic cerebellar gangliocytoma.
1. "Corduroy", striated, or tigroid appearance of cerebellar hemisphere due to thickened, irregular folia.
2. Most commonly unilateral cerebellar hemisphere involvement +/- vermis.
125
CT findings of dysplastic cerebellar gangliocytoma.
1. iso to hyperdense lesion with thickened, irregular, and tigroid folia.
126
MRS of dysplastic cerebellar gangliocytoma.
1. Decreased NAA.
2. Decreased choline.
3. Decreased MI.
127
MR perfusion of dysplastic cerebellar gangliocytoma.
1. Increased relative blood volume.
| 2. Increased relative cerebral blood flow may be present.
128
Basic description of epidermoid cyst.
1. Benign, ectodermal inclusion cysts of congenital or acquired etiology.
129
Pathology of epidermoid cyst.
1. Congenital: arise from ectodermal epithelium in the 3rd-5th weeks of embryogenesis during the process of neural tube closure.
2. Rare acquired lesions are thought to be post-traumatic in etiology, often spinal in location when secondary to LPs.
3. Gross pathologic features include shiny or "pearly" appearance within an outer connective tissue wall.
4. Cysts contain solid cholesterol crystals and keratin.
130
General imaging features of epidermoid cyst.
1. Most cases (90%) are intradural and located within the basal cisterns (CPA, 4th ventricle, parasellar).
2. Minority of cases (10%) are extradural and may arise within the bony calvarium or spine.
131
CT findings of epidermoid cyst.
1. Well-defined, usually hypodense mass similar in density to CSF.
132
T1WI of epidermoid cyst.
1. Signal intensity typically greater than CSF, but less than brain parenchyma.
133
T1WI + C of epidermoid cyst.
1. Typically non-enhancing.
134
DWI of epidermoid cyst.
1. Demonstrates often markedly increased signal (restricts) with corresponding ADC value near that of brain parenchyma (in contrast to an arachnoid cyst which will not restrict).
135
Basic description of ganglioglioma.
1. Slow-growing, well-differentiated, and cortically based neuroglial tumor.
136
Pathology of ganglioglioma.
1. WHO grade I or II.
2. Anaplastic gangliogliomia (WHO III) rare.
3. Dysmorphic ganglion and glial cells.
137
Clinical features of ganglioglioma.
1. Most common tumor-related cause of temporal lobe epilepsy.
2. Associated with NF-1, NF-2, and Turcot syndrome.
138
General imaging features of ganglioglioma.
1. Mixed solid-cystic, enhancing, and cortically based (cyst with mural nodule).
2. Temporal lobe >> frontal and parietal lobes.
3. Associated with adjacent cortical dysplasia, expansion of adjacent cortex.
139
CT findings of ganglioglioma.
1. Variable density and enhancement on contrast enhanced CT.
| 2. Calcification commonly present, hemorrhage rare.
140
T1WI of ganglioglioma.
1. Iso to hypointense relative to gray matter, +/- cortical dysplasia.
141
T2WI of ganglioglioma.
1. Usually hyperintense or heterogeneous, lacks adjacent edema.
142
T1WI + C of ganglioglioma.
1. Moderate, heterogeneous enhancement or non-enhancing.
143
Basic description of glomus jugulare paraganglioma.
1. Benign, neuroendocrine tumor of neural crest origin arising near the jugular foramen.
144
Pathology of glomus jugulare paraganglioma.
1. Arises from glomus bodies which function as chemoreceptors.
2. Located within jugular bulb, CN IX tympanic branch, and CN X auricular branch.
3. Classically spreads through the middle ear in a superior-lateral vector (may involve CN VII mastoid segment).
4. Arterial supply from the ascending pharyngeal artery.
5. Associated with MEN-1, NF-1 and multiple myocutaneous neuromas.
6. Patients are at increased risk of thyroid malignancy.
145
Clinical features of glomus jugulare paraganglioma.
1. Pulsatile tinnitus.
| 2. CN neuropathies (9-12).
146
General imaging features of glomus jugulare paraganglioma.
1. Lobulated solid mass of variable size.
2. Hallmark "salt and pepper" MRI appearance.
3. Involvement of middle ear common, may invade jugular vein or sigmoid sinus.
147
CT findings of glomus jugulare paraganglioma.
1. Soft tissue mass centered near the jugular foramen.
| 2. +/- adjacent permeative-destructive bony changes.
148
T1WI findings of glomus jugulare paraganglioma.
1. Hyperintense "salt" due subacute hemorrhage, hypointense "pepper" due to arterial flow voids.
149
T11WI+C of glomus jugulare paraganglioma.
1. Avid enhancement.
150
MRV of glomus jugulare paraganglioma.
1. May show jugular vein and/or sigmoid sinus involvement/occlusion.
151
PET/CT of glomus jugulare paraganglioma.
1. Avid FDG uptake which may be useful in metastatic evaluation or evaluating treatment response.
152
Basic description of glomus vagale paraganglioma.
1. Benign, hypervascular neuroendocrine tumor of neural crest origin.
2. Less common than glomus caroticum (carotid body tumor) and glomus jugulare.
153
Pathology of glomus vagale paraganglioma.
1. Arises from glomus bodies within CN X nodose ganglion.
2. Composed of chemoreceptor cells of neural crest origin.
3. Arterial supply from the ascending pharyngeal artery.
4. Chief cells rests (zellballen) within fibromuscular stroma are characteristic microscopic features.
154
Clinical features of glomus vagale paraganglioma.
1. Pulsatile, painless lateral neck mass.
| 2. CN IX-XII neuropathies.
155
General imaging features of glomus vagale paraganglioma.
1. Lobulated, enhancing mass centered within the nasopharyngeal/suprahyoid carotid space about 2cm below the jugular foramen.
2. Displaces the ICA anteromedially, jugular vein posterolaterally, and parapharyngeal fat anterolaterally.
3. Hallmark "salt and pepper" MRI appearance.
156
Basic description of hemangioblastoma.
1. Usually benign, vascular, and slow-growing adult cerebellar tumor.
157
Pathology of hemangioblastoma.
1. WHO grade I.
2. Well-circumscribed, highly vascular mass composed of stromal cells and small blood vessels.
3. Associated with VHL (up to 40% of all hemangioblastomas are in patients with VHL).
4. Often multiple, including retinal hemangioblastoma.
158
General imaging features of hemangioblastoma.
1. Posterior fossa mass (supratentorial and retinal HGBLs in VHL patients).
2. Cyst with enhancing mural nodule common morphology but sometimes solid withotu cyst.
3. May have surrounding edema, particularly in the setting of hemorrhage.
159
CT findings of hemangioblastoma.
1. Hypodense cyst.
| 2. Iso to hyperdense solid nodule.
160
T1WI of hemangioblastoma.
1. Isointense nodule +/- flow voids.
161
T2WI of hemangioblastoma.
1. Hyperintense cyst and nodule, possible surrounding hyperintense edema.
162
T1WI +C of hemangioblastoma.
1. Avidly enhancing nodule, nonenhancing cyst, usually without cyst wall enhancement.
163
DWI of hemangioblastoma.
1. Possible DWI-bright, ADC-dark diffusion restriction in cystic component.
164
MRS of hemangioblastoma.
1. Elevated choline.
2. Decreased NAA.
3. +/- lactate/lipid peaks.
165
Basic description of intracranial lipomas.
1. Fat containing developmental or congenital abnormalities of neural crest origin.
2. Rarely neoplastic.
166
Pathology of intracranial lipomas.
1. Arise secondary to abnormal differentiation of the meninx primitiva.
2. Associated with other neural crest congenital anomalies in 60% of cases, often agenesis of the corpus callosum or underdevelopment of the inferior colliculus.
3. Location: pericallosal region or within the quadrigeminal, suprasellar, or CPA cisterns.
167
General imaging characteristics of intracranial lipomas.
1. Well marginated, low attentuation or high signal intensity mass (fat density).
168
CT findings of intracranial lipomas.
1. Hypodense +/- peripheral calcification.
169
T1WI findings of intracranial lipomas.
1. Hyperintense.
170
T1WI+C findings of intracranial lipomas.
1. No enhancement.
171
Basic description of medulloblastoma.
1. Malignant, invasive primitive neuroectodermal tumor usually arising within the posterior fossa.
2. Most common pediatric malignant posterior fossa tumor.
172
Pathology of medulloblastomas.
1. Divided into 4 molecular subtypes which originate in different locations:
- Wingless (WNT): cerebellar peduncles, CPA
- Sonic hedgehog (SHH): cerebellar hemispheres
- Group 3: 4th ventricle, midline
- Group 4: 4th ventricle, midline
173
General imaging features of medulloblastomas.
1. Solid, rounded 4th ventricular mass most common.
2. +/- 4th ventricular effacement and distortion (in comparison with ependymoma, which often expands/enlarges the 4th ventricle).
3. Calcification and cysts occasionally present.
4. Hemorrhage uncommon.
5. CSF dissemination common, including drop mets within the spinal canal (15-50%).
174
Basic description of ADEM (acute disseminated encephalomyelitis).
1. Autoimmune mediated demyelination typically occurring shortly after immunization or upper respiratory tract infection.
