Peds Radiology Case - Benign Brain Tumors

Question 1

List 3 common benign brain tumors.

Answer 1

1. Meningioma
2. Pituitary Macroadenoma
3. Craniopharyngioma

Question 2

Most common intracranial benign tumor?

Answer 2

Meningioma

Question 3

Features of a meningioma (anatomy and appearance on MRI)

Answer 3

Extra-axial
Dural-based
Often calcified
Enhances intensely
Occur along the dura, falx, and tentorium

Question 4

Presentation of a dural based meningioma over the convexity of the brain?

Answer 4

Can be asymptomatic and incidentally discovered

Often slow growing and do not require resection unless symptomatic

Presents a a mass lesion with symptoms related to its location

Question 5

Appearance of meningioma on CT?MRI?

Answer 5

Sharply defined extra-axial tumors with calcifications (20-25%) and intensely enhancing like a light bulb when viewed on post-contrast CT/MRI

Question 6

Calcified tumors are better appreciated on what imaging?

Answer 6

Non-contrast CT image (area of increased density) rather than on pre-contrast T1 weighted MRI

Question 7

Features of a craniopharyngioma?

Answer 7

Suprasellar cystic tumor

Question 8

Pathogenesis of craniopharyngioma?

Answer 8

COmmon in children
Located in suprasellar region
Derived from remnant of Rathke pouch secondary to maldifferentiation of the epithelium
May compress optic chiasm
Can increase ICP due to obstructive hydrocephalus
Usually cystic, often contains calcium

Question 9

Hallmark appearance of craniopharyngioma?

Answer 9

Suprasellar calcified tumor with cystic and enhancing components

Cyst content usually has the same intensity as CSF

Capsule enhances with contrast

Question 10

Systematic approach to evaluating brain tumors in imaging studies - age?

Answer 10

First decade: medulloblastoma, astrocytoma, ependymoma, craniopharyngioma, glioma

Adults: mets (most common), astrocytoma, glioblastoma multiforme, meningioma, schwanoma, pituitary adenoma

Question 11

Systematic approach to evaluating brain tumors in imaging studies - location?

Answer 11

Intra-axial: mets or astrocytoma
Extra-axial: meningioma or schwanoma
Pituitary fossa: craniopharyngioma
Cerebellopontine angle: schwanoma
Ventricles: ependymoma

Question 12

Systematic approach to evaluating brain tumors in imaging studies - number?

Answer 12

Single: primary, solitary mets
Multiple: mets, phacomatoses

Question 13

Systematic approach to evaluating brain tumors in imaging studies - tissue characteristics?

Answer 13

Fat: lipoma, dermoid, teratoma
Calcium: meningioma, oligodendroglioma, astrocytoma, craniopharyngioma
Cystic: non-tumoral cysts

Question 14

Systematic approach to evaluating brain tumors in imaging studies - signal intensity?

Answer 14

T1 - low signal intensity, high signal intensity in melanoma or with hemorrhage

T2 - bright due to water content

DWI

Fat suppression

Question 15

Systematic approach to evaluating brain tumors in imaging studies - enhancement with contrast?

Answer 15

Most enhance due to loss of BBB

Low: low grade astrocytoma, non-tumoral cystic lesion
Homogenous: mets, lymphoma, pilocystic astrocytoma, meningioma
Patchy enhancement: mets, oligodendroglioma, glioblastoma multiforme
Ring: mets, high grade glomas

Question 16

Common location of medulloblastoma?

Answer 16

Posterior to the 4th ventricle involving the vermis

Question 17

DDx of tumor in the 4th ventricle in a child?

Answer 17

Medulloblastoma (more common, roof of ventricle) and ependymoma (floor of ventricle)