Primary Glial Tumors

Question 1

Juvenile Pilocytic Astrocytoma

Answer 1

Usually posterior fossa in children

cystic mass with an enhancing mural nodule

if along optic pathway then can be associated with NF1

Question 2

Low grade astrocytoma

Answer 2

T1 iso, nonenhance

T2 hyperintense

Question 3

Anaplastic astrocytoma

Answer 3

can appear like low grade astrocytoma or like GBM

Question 4

GBM

Answer 4

T1 iso/hypo
T2 hyper w/ lots of adjacent edema

Best imaging clue: Thick, irregularly enhancing rind of neoplastic tissue surrounding necrotic core

Question 5

gliomatosis cerebri

Answer 5

T2/FLAIR hyperintense involvement of at least two lobes + extracortical involvement (bg, corpus callosum, brain steam, or cerebellum)

no enhancement

Question 6

Oligodendroglioma

Answer 6

cortical based mass with tendency to calcify.

CT: Mixed density (hypo-/isodense) hemispheric mass that extends to cortex. Enhancement varies

T1: heterogeneously iso/hypo intense
T2/FLAIR: heterogenously hyper
C+: heterogeneously enhance when it does.

Question 7

Ependymoma (infratentorial)

Answer 7

“toothpaste tumor” fills the 4th ventricle and squeezes thru foramen of magendie or luschka to basl cisterns

NECT: 4th ventricle mass, Ca++ common (50%); ± cysts, hemorrhage, Hydrocephalus common

T1: iso/hypo, part solid, part cystic, hyperintense foci due to Ca or blood common

T2: heterogenous hyper. cystic components hyper. hypointense foci due to Ca or blood common

C+ heterogenous enhance.