Lesion/tumors Flashcards
Astrocytomas can be put in 2 catagories
Diffuse and circusmscribed
Circumscribed astrocytomas (2)
JPA (pilocitic). Subependymal giant cell tumor
Name the entity.
imaging characteristic, enhancement, syndrome)
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Juvenile pilocytic astrocytoma
cerebellar cyst w/ a enhancing nodule. Will enhance even if low grade. Optic glioma in NF1
Name the entity
(where does it arise? Association? WHO classification
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Subependymal giant cell astrocytoma
Large lobulated, vividly enhancing mass. Usually at foramen of monro. rises from lateral wall of ventricles.
a/w Tuberous sclerosis
WHO grade 1
Fibrillary astrocytoma - describe and name the 3 types
Infiltrative tumors that can occur anywhere in CNS. 3 types are Low grade (WHO2), anaplastic (WHO 3), and GBM (WHO4).
Low grade is a T2 bright thickened cortex, GBM is an irregular enhancing lesion.
Fibrillary astrocytoma - low grade type - imaging.
Hyperintense T2 w/ no enhancement. Thickened cortex
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Fibrillary astrocytoma - Anaplastic type - imaging
WHO3 - between low grade and gliomatosis cerebri. From thickened cortex to irregularly enhancing mass.
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GBM characteristics
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WHO4 Heterogenous RIM enhancement, classic for crossing midline, can restrict, peritumoral spread leads to underestimation of size (spreads though white matter, CSF and subependymally)
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Name the entity
parameters for diagnosis
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Gliomatosis cerebri
WHO 2-3, Diffuse glioma with extensive infiltration, involves at least 2 lobes and extracortical involvement (basal ganglia, corpus callosum, brainstem, cerebellum. extensive T2 hyperintensity and little mass effect. May not enhance.
Things that cross midline (4) (2 tumors, a disease, and an iatrogenic thing)
GBM, Lymphoma, Tumofactive MS plaque, radiation
Tumors that classically restrict diffusion (3)
Lymphoma (homoenous), GBM (heterogenous), medulloblastoma
Name
Benign or malignant?
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Choroid plexus xanthogranuloma.
Totally benign cyst. Restricts diffusion.
Lesion characteristics (enhancement, diffusion, nuc medicine finding (thallium or gallium?)
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CNS lymphoma
Periventricular. Dense on CT. Homogenous enhancement, can cross midline, Restrict diffusion, thallium positive.
Usually B-cell lymphoma. “melts” away w/ chemo treatment.
immunocompromised patient: enhancing periventricular mass that crosses midline.
Immunocompetent: enhancement without central necrosis.
Ddx for diffuse T2 hyperintensity in brain (4)
Gliomatosis cerebri, PML, HIV encephalopathy, Lymphoma
Tumors that calcify (Old elephants age gracefully is a mneumonic that goes in order of frequency)
Oligodendroglioma, ependymoma, astrocytoma, GBM.
Classic tumor that calcifies
Oligodendroglioma
Tumor name
demographics
imaging
location
prognostic factor
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oligodendroglioma
Young to middle aged patient with seizures
Calcifies, cortically based, expands cortex
likes frontal lobe
Important prognostic factor is 1p.19q deletion.
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Ddx Cortical based tumors (DOG)
Dysembryoplastic neuroepithelial tumor (DNET), Oligodendroglioma, Ganglioma
Name the lesion
Demographics
Imaging
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Dysembryoplastic neuroepithelial tumor (DNET)
Kid w/ refractory seizures.
Bubbly, cortical, T2 bright lesion in temporal lobe.
Name the lesion:
epidemiology, imaging, enhancement
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Bimodal (1-5 years (in posterior fossa) or >40 years (in spine)), soft/plastic tumor (toothpaste), low cellularity, Avidly enhances. Calcium and hemorrhage in 50%, origniate from floor of 4V)
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Name the lesion
(Official name, WHO grade, association, histologic composition)
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Corduroy/tiger striped lesion in cerebellar hemisphere
Lhermitte-Duclos (AKA dysplastic cerebellar gangliocytoma). T1 hypointense/nonenhancing. T2 - Tiger stripes.
WHO1
a/w cowden syndrome
Part hamartoma, part neoplasm.
Embryonal tumors. What are they. 2 types
WHO grade 4 Primitive neuroendocrine tumors.
ATRT, medulloblastoma
Atypical teratoid/rhabdoid tumor
WHO4, aggressive, looks like medulloblastoma but occurs in younger patients and is more aggressive
Medulloblastoma (age, CT characteristics, MR (T2, ADC,enhancement), classic enhancement pattern. Location. Difference in location if it arises in adult.
75% < 10yo, spherical, highly cellular which means it is slightly higher density on CT, hyperintense on T2, low on ADC. homogenous calcium, arises from medullary velum (roof of 4V), but it may arise eccentrically in cerebellum in an adult.
Cyst w/ a nodule (4)
JPA, hemangioblastoma, Pleomorphic xanthoastrocytoma, ganglioma
Cyst w/ nodule - breakdown by location
JPA (kid) and hemangioblastoma (adult) are infratentorial, PXA and ganglioma is supratentorial
Hemangioblastoma (WHO1), syndromic association, where, appearance, when in spinal cord, what is it associated with.
VHL, cerebellum, medulla, or spinal cord. Cystic mass with mural nodule. Vascular. When in spinal cord, a/w syrinx
PXA vs. ganglioma imaging distinction
PXA has dural tail, ganglioma has no dural tail
PXA (WHO2) (pleomorphic xanthroastrocytoma), location, appearance. Demographics/clinical presentation. What is an identical entity, but seen only in infants?
Temporal lobe, invades leptomeninges. Dural tail. It occurs in childhood and adolescents, a/o epilipsy. In infant it would be called a Desmoplastic infantile ganglioglioma
Ganglioma imaging.
Cyst w/ nodule. Variable appearance, but nodule usually enhances. in temporal lobe. Presents in adolescent w/ seizures.
Intraventricular tumors (5)
Central neurocytoma, chroroid plexus papilloma/carcinoma, intraventricular meningioma, subependymal giant cyst astrocytoma (SEGA), subependymoma
Central Neurocytoma (epidemiolgy/prognosis, typical imaging)
Low grade, good prognosis. Lobulated mass attached to septum pellucidum w/ numerous intratumoral cystic areas. Frequently calcified.
Choroid plexus papilloma(WHO1)/Carcinoma (WHO3) - epidemiology, MRI imaging. Most common location in Children and adults.
Papilloma is most common brain tumor in babies <1year old. T2 intense/heterogenous, enhances. In children it occurs in atrium and lateral ventricle. In adults ints in 4th ventricle. Choroid plexus carcinoma is not distinguishable.
Intraventricular meningioma - where? Epidemiology?
Trigone. Older patients.
Subependymoma, epidemiology, location/imaging.
Benign (who 1), adult, often incidental. Inferior aspect of 4th ventricle. Nonenhancing. (Subependymoma is not related to ependymoma or SEGA. And its pretty benign and found incidentally, like a substitute)
Tumor that occurs supratentorially in kids, and infratentrially in adults (opposite of rule)
Choroid plexux papilloma/carcinoma. Pediatric = lateral trigone. In adult = 4th ventricle. High enhancing. Calcified, hydrocephalus.
CNS lymphoma (etiology, general apperance)
Large B cell lymphoma. Lymphoid from cerebral blood vessels (because brain does not have native lymphoid), Periventricular highly cellular mass. Further imaging details depend on immune status)
CNS lymphoma in immunocompetent patient
Enhancing periventricular mass (no necrosis). Can cross midline
CNS lymphoma in immunocompromised patient.
Periventricular ring-enhancing lesion in basal ganglia. Ring enhancement due to central necrosis.