Brain by location Flashcards
Posterior fossa mass (PEDS)
- Juvenile pilocytic astrocytoma
- Medulloblastoma / PNET[M>F, superior medullary velum; midline, tend to compress/displace 4th ventricle, calc/hemorrhage<5y, supratentorial 40%, infratentorial 50%, favour over medulloblastoma if it extends to CPA, CT – hyperattenuating, cysts, hemorrhage, vasogenic edema, enhancement variable, T1 iso/hypo, T2 variable, subarachnoid seeding]
Supratentorial mass (PEDS)
- PXA
- Supratentorial PNET [usually <2y)
- Dysembroplastic neuroepithelial tumor (DNET)
- Ependymoma [intraparenchymal when supratentorial]
Posterior fossa mass (ADULT)
• Solitary metastasis o Lung o Breast • GBM • Hemangioblastoma [20% have VHL, 45% w/ VHL have CNS hemangioblastoma, VHL: multiple 40%, cerebellum, retina, medulla, spinal cord; panc, renal, liver, epididymal, ovarian cysts, RCC, pheo; VHL criteria: >1 CNS +/or retinal hemangioblastoma; CNS hemangioblastoma + >= 1 visceral abnormality; >=1 visceral abnormality + fam hx VHL] • Medulloblastoma / PNET • Ependymoma • Cerebellar liponeurocytoma • Dysplastic Cerebellar Gangliocytoma (Lhermitte-Duclos disease) [poorly demarcated, slightly hypoattenuating, calc uncommon, “striated” T1 dark, T2 bright mass, no edema, no enhancement, mild mass effect, thickening of folia -> laminated appearance; assoc Cowden dx]
Supratentorial mass (ADULT)
- Solitary metastasis
- GBM
- Gliosarcoma
- Astrocytoma
- Oligodendroglioma [younger, frontal mc, cortical involvement, calc]
- Oligoastrocytoma
- Anaplastic oligodendroglioma
- Gliomatosis cerebri [peak 20-30s, extensive infiltrative WM abnormality, no necrosis, no circumscribed mass, minimal enhancement, mild diffuse sulcal and ventricular effacement, syx out of proportion to degree of infiltration]
- PXA (frontal 30%]
- Hemangioblastoma [solid usually when supratentorial]
Multiple intra-axial masses
• Metastases o Lung o Breast o Melanoma o RCC o GI • Multicentric astrocytomas • Lymphoma
Corpus Callosum Lesion
• Neoplasm o GBM o Lymphoma o Metastasis • White Matter Disorders o MS o PML o Adrenoleukodystrophy o Marchiafava – Bignami disease o PRES • Trauma o Diffuse axonal injury • Stroke • Lipoma
Temporal lobe mass
- Oligodendroglioma
* PXA (<30y)
Unilateral or Bilateral mesial temporal lobe T2/FLAIR hyperintensity
• Herpes simplex encephalitis Type 1 [mass effect – gyral expansion, sulcal effacement, loss of gray-white, +/- hemorrhage, asymmetric, temporal lobes – typically medial, insula, inferior frontal lobes, cingulate gyrus, cortical gyriform enhancement]
• Paraneoplastic limbic encephalitis [no mass effect, subacute; mc hippocampus, amygdale, insula, gyri; +/- mild enhancement]
o SCLC
o Breast
o Testicular
o Hodgkin’s lymphoma
o Thymoma
o Ovarian CA
o GI CA
o Neuroblastoma [peds]
• Mesial temporal sclerosis [atrophic hippocampus, focally T2 hyper, ipsilat enlargement adj temporal horn; ddx – cortical dysplasia, primary brain neoplasm]
• Infarct [restricted]
• Astrocytoma [mass effect, infiltrating, not restricted, low-grade no enhancement, anaplastic may have heterogeneous enhancement, +/- necrosis, incr choline peak on MRS, decr NAA usually seen but can also be decr with infarction and encephalitis]
• Met [mass effect]
• CO intoxication [GP also involved]
Extra-axial Mass
• Neoplasm o Meningioma Atypical Malignant Radiation-induced Mesenchymal o Hemangiopericytoma [no calc, bone erosion, broad or narrow dural attachment, large >2cm, CT – hyperdense, assoc edema adj brain, MR – T1/T2 iso, heterogeneous, flow voids] o Schwannoma o Metastasis Breast Lung Prostate Melanoma Lymphoma Plasmacytoma Neuroblastoma (ped) Leukemia (ped) o Melanoma Melanocytoma Melanocytosis (ped) o Craniocerebral plasmacytoma [distinct entity from multiple myeloma; arises from crainum or dura; T2 hypointense; avid enhancement] • Sarcoid • Amyloid
CPA mass (VMEN)
• Vestibular schwannoma [60-90%, NF-2 bilat, IAC widening, isodense to cerebellum, T1 iso/hypo, T2 hyper, intense enhancement, no dural tail, calc & hemorrhage rare, may have cystic degeneration; NF-2: bilat vestibular schwannoma OR 1 vestibular schwannoma + 1st deg relative with NF-2 OR 2 schwannoma, meningioma and/or ependymoma + 1st deg relative with NF-2; look for MISME, choroid plexus or cortical calc]
• Meningioma [3-7%, broad dural base, obtuse angle, hyperostosis, hyperdense, T1 iso to GM, T2 variable, IAC involvement uncommon 16%]
• Neuroepithelial cyst
o Epidermoid cyst [2-6%, T1 mildly hyperintense to CSF, T2 isointense to CSF, typically heterogeneity detectable, mildly hyperintense on FLAIR, no enhancement, restricted, lobulated, scalloped, insinuating, tends to encase vessels, CPA cistern, suprasellar cistern, cistern magna, peripineal region]
o Arachnoid cyst [follow CSF on all pulse sequences, no restriction, tends to displace vessels]
• Non-vestibular schwannoma [1-5%, V, VII]
CPA mass (others)
o Ependymoma o Lymphoma o Medulloblastoma o Pilocytic astrocytoma o Paraganglioma o Lipoma o Dermoid o Teratoma o Choristoma o Metastasis • Melanoma [T1 hyper, T2 hypo, ill-defined margins, lack of cystic degeneration, lack of IAC expansion, enhancement]
Pineal region mass [elevation of internal cerebral veins, compression of tectal plate and aqueduct of Sylvius]
• Germ cell origin
o Germinoma [mc pineal region tumour,»_space;F, engulf calc, NCCT hyperdense, avid enhancement, T1 hetero, T2 iso]
o Teratoma [<7y is suspicious; difficult to ddx btwn small natural calc and calc in tumour matrix]
o Pineocytoma [any age but usually adult]
• Astrocytoma
• Pineal cyst
Sella mass that is T1 bright
- Rathke cleft cyst [usually centered within sella although can extend into suprasellar region, usually T1/T2 bright but variable, no enhancement or mild peripheral enhancement]
- Hemorrhagic pituitary adenoma
- Craniopharyngioma [calc, assoc ST mass, +/- areas of solid enhancement]
- Neuroenteric cyst
- Epidermoid cyst
- Traumatized arachnoid cyst
Suprasellar mass
• Germinoma (<30y)
Suprasellar mass DDx (SATCHMO)
- Pituitary macroadenoma [mc, >1cm, suprasellar extension, gland and mass can’t be separated, cystic, hemorrhagic changes]
- Meningioma [usually lateral, thin black line of diaphragm sellae separates mass from pituitary, dural tail sign]
- Aneurysm [arise from COW, partial/complete thrombosis common, occasionally basilar artery aneurysm can project into suprasellar cistern]
- Craniopharyngioma [90% calc, 90% cystic, cystic and solid, 90% enhance (rim +/- nodule), mc suprasellar mass in child, 2nd peak 40-50s, variable signal]
- Astrocytoma [2nd mc in peds, rare adults]
- AVM
- Arachnoid cyst
- Teratoma [contains fat and calc, midline, looks the same as dermoid cyst, risk of rupture]
- Dermoid cyst [fat-like +/- droplets, +/- peripheral calc, near midline, also frontal, basal surface of brain, quadrigeminal cistern, 4th ventricle; risk of rupture]
- Germinoma [stalk +/- gland]
- Rathke’s cleft cyst [usually centered within sella although can extend into suprasellar region, usually T1/T2 bright but variable, no enhancement or mild peripheral enhancement]
- Choristoma
- Hypothalamic glioma
- Hamartoma of the tuber cinereum [floor of 3rd ventricle, ant to mamillary bodies, precocious puberty, gelastic sz; T1 iso to GM, T2 iso/hyper, no enhancement; if >1.5cm or marked T2 hyper, consider possibility of hypothalamic glioma -> f/u imaging b/c hamartoma shouldn’t grow]
- Histiocytoma
- Sarcoidosis [thickened stalk, dural based masses]
- LCH [thickened stalk, child with DI]
- Lipoma
- Metastasis
- Optic glioma
