2 Course ECONR

Pilocytic Astrocytoma
Subependymal Gaint Cell Astrocytoma
Pleiomorphic Xanthoastrocytoma

Most common glioma in children
Corresponds to WHO grade I
Most frequent locations are:
- Cerebellum: 85%
- Hypothalamic/third ventricular region
- Optice neve/chiasm
- Dorsal brain stem
*

Cerebellar
large cyst with mural nodule
nodule enhances strongly
Midline tumours
solid mass
diffuse enhancement, possibly heterogeneous
small cysts possible

Mostly associated with tuberous sclerosis
Other signs of tuberous sclerosis (cortical
tubers, subependymal calcifications)
present
Rounded, calcified and strongly enhancing
mass near the foramen of Monro
Frequently (acute) hydrocephalus

Rare tumors of children and young adults
Cerebral hemispheres, mostly temporal
Can be malignant
Can present as:
- cyst with a mural nodule which is
attached to the leptomeninges
- solid mass
Enhancement is intense and represents
hypervascularity

siehe Bild

Is considered essential:
For characterising a new lesion as
malignant
For diagnosing malignant
transformation of a previously benign,
non-enhancing lesion

Non-enhancing tumors are
considered grade II

40% (obwohl eine nicht anreicherung für gewöhnlichs Grad II angebenen wird

Slow-groing tumor with propensity to
involve the cortex
Very heterogeneous tumor making
histologic grading difficult
Mixed oligo-astrocytoma is frequent

Genetics are very important. Loss of 1p and
19 q dramatically changes (improves) the
prognosis of the patiënt
Oligodendroglioma: 1p

Most important imaging hallmarks are:
Cortical location or extension
Streaky calcifications imaging characteristics
- are not mandatory
- can have a very misleading appaerence on MR
Patchy or more diffuse enhancement that
does not necessarily represents
malignant transformation!!
*

Infratentorial: mostly in children
fourth ventricle
calcification frequent
platicity: lateral extension through foramen of
Luschka
inhomogeneous enhancement

Is mostly supratentorial
If totally intraventricular: to be
differentiated from central neurocytoma,
meningioma, astrocytoma
If not totally intraventricular
(70 % in adults) : can be indistinguishable
from malignant astrocyoma
Calcification frequent
*

Arise from choroid plexus epithelium
Comprise benign papilloma (grade I)
and carcinomas (grade III)
Lateral ventricle: 80 % children
Can produce CSF with hydrocephalus

Cauliflower-like intraventricular mass
Calcification frequent
Marked enhancement

Young patients with chronic focal
epilepsy
Well-delineated cortically based
cystic neoplasm with enhancing nodule
Temporal or occipital location

Neuronal tumor of young adults
In lateral ventricles, attached to the
septum pellucidum
Multicystic masses possibly calcified with
variable enhancement
Despite of the obvious benign character, seeding in venble

Meningiomas
Schwannomas

Metastases
 Lymphomas
Maldevelopmental cysts and tumors
 Osseous lesions
 Sellar and parasellar lesions

ossär

lipoblastisch

subcortical

Benign,slow growing
5-10% of all CNS Tumors
F > M (Intracranial)
30's - 60's

Sensory Nerves (usually):
– CNS VIII (Sup.Vestibular), V, X
 Majority (>90%) are Sporadic
 Multiple in NF-2, 10’s – 30’s, Bilat.VIII pathognomonic

Vast majority intracerebral non-Hodgkin

intracerebral (64%) ,dural (20%)

Arachnoid cysts
Epidermoids
Dermoids
Colloid cysts
 Neurenteric cysts
 Neuroglial cysts

Lipoma

•Congenital endodermal cysts.
•Lined by mucin-producing epithelium
•Ventral to spinal cord (craniocervical junction)

• Not tumors, malformations
• Incidental findings
• Locations: Corpus callosum, supravermian
region, CPA, hypothalamus

• Chordoma
• Chondrosarcoma
• Eosinophilic granuloma

Epidermoid

•Belongs to the group of histiocytosis X
•Skull is frequent location (25%)
•Lytic lesion with "beveled edges"

•Off midline mass at the petro-occipital fissure

•Congenital inclusion of ectoderm in the diploic space
•Round, frequently lobulated lytic lesion
•Displacement of inner and outer tables
•Thin well defined sclerotic border
•MRI: On T1 and T2 iso- or slightly hyperintense. DWI

Hemangiopericytomas
Solitary fibrous tumors (SFT)
Meningeal melanocytomas
 Gliosarcomas
Meningeal fibrosarcomas

Endolymphatic sac tumor
Rosai Dorfman disease
Plasmacytoma
Sarcoidosis

1. susceptibility contrast-enhanced (DSC) MR
2. perfusion dynamic contrastenhanced (DCE) MR perfusion.
3.  arterial spin labeling (ASL) MR

• Allows quantitative assessment of the bloodbrain barrier and microvascular permeability
• more complete assessment of brain tumor angiogenesis

Advantages:

most commonly used to evaluate brain
tumors
easier to use
available post-processing software
 

Limitations
Quantification
susceptibility artifacts (i.e., blood product,
calcification, metal, air, and bone)
user dependence

Low-grade gliomas with rCBV>1.5 are more likely
to evolve into high-grade gliomas than those with
lower rCBV values

A low-grade glioma with detectable areas of high
permeability (micro-vascular leakage) presents a two-fold
risk of recurrence

Perfusion MRI in the peritumoral area of metastases can differentiate them
from HGG.

• Different perfusion profile from HGG due to peritumoral pathophysiology:
• No histologic evidence of tumor beyond the outer contrast-enhancing margin of the metastasis.
• Peritumoral region represents reaction of the surrounding intrinsically normalbut edematous brain parenchyma.