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124 Cards in this Set
- Front
- Back
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What are 7 aspects that can be used to figure out the etiology of a tumor
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-pt age
-location -CT/MR characterisitic -MR signal characteristic -Enhancement -Mass effect -Multiplicity |
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What 3 aspects about location can help determine what type of tumor
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intra Vs extra
compartment midline crossing |
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What are 3 CT/MR characteristics that can narrow down a tumor type
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fat, cystic, calcification
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What is meant by signal characterisitc
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T1, T2, DWI
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What is the signal characteristic of most brain tumors
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low on T1 and high on T2
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What is the rough approximation of percentage of mets, glioma and non-glial brain tumors
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33% each
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What are the types of glial cells
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astrocytes, oligodendrocytes, ependymal and choroid plexus cells
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What are the main subdivisions of astrocytes
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Astrocytoma is the most common glioma and can be subdivided into the low-grade pilocytic type, the intermediate anaplastic type and the high grade malignant glioblastoma multiforme (GBM)
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What is the most common astrocyte
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GBM is the most common type (50% of all astrocytomas).
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What is the most common glial cell
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astrocytoma
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What is the most common non-glial cell
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meningioma
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What are 3 tumors that tend to occur under 2 years of age
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Specific tumors occur under the age of 2, like choroid plexus papillomas, anaplastic astrocytomas and teratomas
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What are the tumors by age
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What tumors are common during the first decade of life
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In the first decade medulloblastomas, astrocytomas, ependymomas, craniopharyngeomas and gliomas are most common,
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What is rare during the first decade of life
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mets
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What is the MC mets in the first decade of life
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When they do occur at this age, metastases of a neuroblastoma are the most frequent
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What makes up 50% of all CNS lesions in adults
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mets (notice how since it is less in children it balances out and is 33% overall)
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What are the common tumors of adults
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Other common tumors in adults are astrocytomas, glioblastoma multiforme, meningiomas, oligodendrogliomas, pituitary adenomas and schwannomas.
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What is tumor that will occur at any age
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Astrocytomas occur at any age
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What is a tumor that tends to occur in older adults and elderly
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mets
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What is the 3rd most common cancer after leukemia and lymphoma in children
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primary brain tumors (as a group)
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Where do most tumors occur in children
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Most of the tumors in children are located infratentorially
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What are the common infratentorial tumors in children
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Juvenile pilocytic astrocytoma
PNET (meduloblastoma) Ependymoma Brainstem Astrocytoma |
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What are the common supratentorial tumors that occur in children
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astrocytoma
pleomorphic astrocytoma PNET DNET Ganglioglioma |
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Do the mets make up 50% of adult brain tumor of which 50% are solitary
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yes
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Where do mets MC appear
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infratentorial
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What are the 2 MC infratentorial cancers in adults
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hemangioblastoma
mets |
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What are the MC supratentorial cancers in adults
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mets
gliomas (fibrillary astrocytoma, anaplastic astrocytoma, GBM, oligodendroglioma) |
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What 2 tumors make up 80% of extra-axial tumors
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meningioma and schwannoma
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What percent of intra-axial tumors in an adult are mets or astrocytoma
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75%
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Name 6 signs of an extra-axial tumor
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CSF cleft
Displaced subarachnoid vessels Cortical gray between mass and white matter Displaced and expanded SA space Broad dural tail Bony reaction |
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What extra-axial tumors tend to cause bony changes
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Bony changes are seen in bone tumors like chordomas, chondrosarcomas and metastases
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Can bony change occur from secondary change by a meningioma
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yes
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Why do most extra-axial tumors enhance avidly
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Extra-axial tumors are not derived from brain tissue and do not have a blood-brain-barrier, so most of them enhance homogeneously
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How do astrocytomas spread
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Astrocytomas spread along the white matter tracts and do not respect the bounderies of the lobes
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If you see a 4th ventricle tumor in a child extending through the foramina what should you suspect
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ependymoma
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What is a characteristic spread of a oligodendroglioma
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Oligodendrogliomas typically show extension to the cortex
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Some tumors show subarachnoid seeding and form tumoral nodules along the brain and spinal cord. What tumors do this
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This is seen in PNET, ependymomas, GBMs, lymphomas, oligodendrogliomas and choroid plexus papillomas
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What are PNET
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Primitive neuroectodermal tumours (PNET) form a rare group of tumors, which develop from primitive or undifferentiated nerve cells
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What are 2 common types of PNET
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These include medulloblastomas and pineoblastomas
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What tends to have more mass effect; primary or mets
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mets
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What is the ddx of tumors that cross the midline
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GBM
Radiation Necrosis Meningioma Lymphoma Epidermoid Cyst MS |
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What are some common causes of multifocal brain lesions besides Mets
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Lymphoma
Multicentric GBM Gliomatosis Cerebri |
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What are the causes of brain tumors that can seed and therefore be multifocal
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medulloblastomas (PNET-MB), ependymomas, GBMs and oligodendrogliomas
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What condition may result in menigioma and schawnomas to become multible
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NF 2
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What tumors are seen in NF 1
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optic glioma and astrocytoma
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What tumors are seen in NF 2
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meningioma
ependymoma choroid plexus tumors (schwannoma?) |
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What tumors are seen in TSC
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subependymal tubers, intraventricular giant cell astrocytomas, ependymomas
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What tumor is seen in VHL
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hemangioblastomas
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Why does a tumor being located in the gray matter help narrow the differential ddx
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because most tumors are located in the white matter
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What is the ddx of a tumor in the grey matter
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oligodendroglioma, ganglioglioma and Dysembryoplastic Neuroepithial Tumor (DNET)
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What is a DNET and where is it commonly located
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A DNET is a rare benign neoplasm, usually in a cortical and temporal location.
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What is the MC presentation in patients with cortically based tumors
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seizures
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An infiltrative mass with calcification that extends to the cortex
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oligodendroglioma
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What are the most common brain tumors that contain fat
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lipomas
dermoid cysts teratomas |
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Name 3 tumors that may have high density on CT
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lymphoma, colloid cyst and PNET-MB (medulloblastoma).
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Do oligodendrogliomas always have calcification
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yes
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What is the ddx of a calcified intra-axial brain mass
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oligodendroglioma
astrocytoma mets ependymoma choriod plexus papilloma ganglioglioma |
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What are the 3 most commonly calcified brain tumors
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oligo...
ependymoma ganglioglioma |
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Does a pineocytoma calcify
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No, A pineocytoma itself does not calcify, but instead it 'explodes' the calcifications of the pineal gland.
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Calcified mass in the suprasellar region
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craniopharngioma (not in previous ddx)
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Describe a craniopharyngioma
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Craniopharyngiomas are slow growing, extra-axial, squamous epithelial, calcified, cystic tumors arising from remnants of Rathke's cleft
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What are 5 lesions that are cystic and can simulate a CNS tumor
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These include epidermoid, dermoid, arachnoid, neuroenteric and neuroglial cysts
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What is a way to differentiate an arachnoid cyst from a necrotic (cystic) tumor
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Tumor necrosis may sometimes look like a cyst, but it is never completely isointense to CSF.
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Do craniopharyngiomas have an enhancing rim
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yes
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Can a high protein cyst be bright on T1
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yes
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What are 2 reasons brain tumors tend to have increased signal on T1
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hemorrhage or melanin in the case of mets
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Why are most tumors bright on T2
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due to a high water content
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What cause tumors to be dark on T2
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When tumors have a low water content they are very dense and hypercellular and the cells have a high nuclear-cytoplasmasmic ratio.
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What are 2 examples of tumors that are dark on T2 because of high cellularity
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CNS lymphoma and PNET
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Do cns lymphoma and PNET appear bright on CT
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yes
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What is the usual appearance of calcification on T2
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dark
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What is the appearance of hemosiderin on MRI
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dark
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Can protieinacious material be dark on T2 imaging
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yes
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What is an example of a proteineous cyst that is dark on T2
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colloid cyst
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What is an example of a tumor that has flow voids (dark on T2)
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hemangioblastoma (VHL)
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What are causes of tumors with low signal on T2
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hypercellular
flow void melanin certain proteinaceous material certain phases of hemorrhage calcification mucinous mets |
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Does mucinous mets have low signal on T2W images
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yes
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Can meningiomas be either high or low signal on T2
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yes, depending on cellularity and amount of calcification
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What does high intensity on DWI indicate
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fluid restriction
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Name 3 causes of restricted diffusion in the brain
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abscesses, epidermoid cysts and acute infarction (due to cytotoxic edema).
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What is the cause of restricted diffusion of an abscess
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In cerebral abscesses the diffusion is probably restricted due to the viscosity of pus, resulting in a high signal on DWI.
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Do tumors usually have restricted diffusion
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no
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Can perfusion imaging play an important role in malignancy grade
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yes
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What is perfusion dependent on
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the vascularity of the tumor and not the blood brain barrier
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What shows greater association with the grade of malignancy; enhancement or perfusion
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perfusion
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What is the only way contrast leaks into the brain
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if the blood brain barrier is broken down when a tumor destroys it
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Why do extra-axial tumors tend to enhance
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they are not from the brain tissue and therefore do not have a BBB
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What intra-axial tumors commonly enhance
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high grade glioma
low grade glioma (ganglioma, pilocytic astrocytoma) lymphoma mets |
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What low grade gliomas enhance
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gangliolioma
pilocytic astrocytoma |
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What non-tumours lesion enhance
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infections, demyelinating diseases (MS) and infarctions.
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Does contrast enhancement illustrate the full entension of a tumor
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no, it wont tumor cells will be found beyond the enhancing margins
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In gliomas does enhancement usually indicate a higher degree of malignancy
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yes
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What is a sign of malignant transformation of a low grade glioma
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enhancement of followup imagin
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What is the optimal timing for delay on contrast in brain tumors
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The optimal timing is about 30 minutes and it is better to give contrast at the start of the examination and to do the enhanced T1WI at the end
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What tumors do not enhance
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low grade astrocytomas
cystic (dermoid, epidermoid, arachnoid cyst) |
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What type of tumors tend to have homogenous enhancement
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Metastases
Lymphoma Germinoma and other pineal gland tumors Pituitary macroadenoma Pilocytic astrocytoma and hemangioblastoma (only the solid component) Ganglioglioma Meningioma and Schwannoma |
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What tumors tend to have patchy enhancement
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Metastases
Oligodendroglioma Glioblastoma multiforme Radiation necrosis |
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Do GBMs have variable enhancement and heterogeneity on both T2WI and FLAIR.
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yes
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What brain tumors will have ring enhancement
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Ring enhancement is seen in metastases and high-grade gliomas.
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What are the causes of ring enhancement
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mets
abscess glioma infection chronic hematoma demyelating disease radiation |
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Is leptomeningeal enhancement easy to see on T2
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NO, only possible to see with T1 plus gad
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What are the common skull base brain tumors
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chordoma
chondrosarcoma esthesioneuroblastoma lymphoma mets myeloma paraganglioma sinonasal carcinoma |
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What is a good way to differentiate a skullbase chordoma from a chondrosarcoma
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Chordomas will be midline where as chondrosarcomas will be off midline
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Is a metastatic lesion a common skull base lesion
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yes
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What would cause lytic destruction of the skull base off midline by the jugular bulb
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a paraganglioma
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Is the normal clivus (bone) bright or black on T1W images
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bright because of the fatty bone marrow
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What are the common sella/suprasellar masses
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S
Schwannoma sphenoid sinus tumor A aneurysm / adenoma of pituitary T teratoid lesion C craniopharyngioma H hypothalamic glioma / histiocytoma M meningioma / mets O optic glioma |
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Beside SATCHMO what other tumors can be found in the sella/suprasellar region
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Dermoid
Epidermoid Germinoma Rathkes Cyst Hamartoma Arachnoid Cyst Chordoma |
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What is the MC suprasellar lesion
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craniopharyngioma
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Do craniopharyngiomas have a cystic component and variable amounts of peripheral enhancement and calcifications
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yes
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What is a common complication of a suprasellar lesion
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hydrocephalus
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Would you expect to see an inferior displaced normal appearing pituitary gland in a patient with a pituitary macroadenoma
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no
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What are 6 common CP angle tumors
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schwannoma
meningioma epidermoid arachnoid cyst paraganglioma mets |
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Can a schwannoma be cystic
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yes
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What are the common pineal region tumors
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pineocytoma
GCT PNET Tectal Glioma Meningioma Dermoid Arachnoid cyst |
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What are the common intraventricular tumors
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Ependymoma
Subependymoma Choroid Plexus Papilloma Central Neurocytoma Colloid Cyst Meningioma Giant cell astrocytoma |
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What are the most common tumors of the 4th ventricle in children
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astrocytoma
medulloblastoma ependymoma brainstem glioma with dorsal exophytic extension |
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What are the MC adult 4th ventricle tumors
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Metastases are most frequently seen, followed by hemangioblastomas, choroid plexus papillomas and dermoid and epidermoid cysts.
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What percent of ependymomas are supratentorial
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1/3 supratentorial, majority periventricular WM
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Is calcification of a ependymoma common
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yes they can calcify(50%)
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Can ependymomas have cyst and hemorrhage
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yes
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Ependymoma signal
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MR: iso to hypo T1, iso to hyper T2
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Ependymoma enhancement characteristics
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Enhances heterogeneously
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