6. Learning objectives
Basic appearances of pediatric brain tumors
(focus on brainstem and cerebellum)
What’s new … and what we need to know as
rediologists
Pitfalls & mimics
10. Patient 1
Patient 2
• multiple enhancing
nodules and presence of
cystic components
• Nodular or desmoplastic
SHH !!!
CAVEAT: ADC not always dark (lower
cellularity)
11. Sonic Hedgehog Medulloblastoma (SHH)
cerebellar granule neuron progenitors
(CGNPs)
Purkinje Cells
SHH
1 proliferation
2 migration
Tumorigenesi
s
Huang S and Yang J. 2015 Hatien M and Heintz N. 1995
12. D’Arco F and Bisdas S. 2018 (in press)Perrault et al 2014
14. Medulloblastoma group 3 and 4 (non-SHH / non-WNT)
Genetic basis of this forms and embryological origin are not known.
• Considered pure midline/4th ventricle tumours.
• Poor prognosis (metastatic dissemination)
• Sometimes do not enhance
21. Other embryonal tumors : ↑DWI ; ↓ADC
Embryonal tumours with
multilayered rosettes (ETMR)
• Previously known as ETANTR or CNS
PNET.
• C19MC amplification
• Children < 2
• Large mass with poor enhancement
23. Pilocytic Astrocytoma
• Slow growing tumour in the cerebellar hemisphere or
brainstem.
• Absence of relevant diffusion restriction
• Marked enhancement and presence of cystic
component
27. Diffuse Midline Glioma (DMG)
-aka: Diffuse intrinsic pontine gliomas
• Tumour centered in the pons which is expanded with
effacement of the surrounding CSF spaces
• Typical encasement of the basilar arteries
• Usually do not enhance; localized areas of enhancement are
possible
• H3 K27 mutant, variable histology
30. Diffuse Midline Glioma (DMG)
-supratentorial and spinal locations
Midline vs off-midline
Patay Z. 2016
31. Ependymoma
• Posterior fossa mass with plastic extension through the
outlet foramina of the IV ventricle and ponto-cerebellar
angle (toothpaste appearance).
• Heterogeneous: calcium, haemorrhages, cysts (“the
ugly”)
• Generally ADC values are intermediate between PA and
embryonal (areas of low ADC = anaplastic)
36. Tumour like lesion: resemble a tumour but is
not…
• Presence and pattern of enhancement
• Mass effect
• Infiltration
• Edema
• Signal characteristics
37. Tumour like lesion
• Optic neuritis
• Muscle weakness
• Bladder problems
• Complete recover
NMO-SD ; MOG Ab +
• Problems with
eye movements
• Facial drop
DIPG
• Optic glioma
• Cafè-au-lait spots
NF1 related FASI
• Acute hearing
impairment
• Unilateral leg
weakness and
numbness
Pontine stroke
Don’t forget that you are
clinical radiologists !!!
38. Case : 16 y M, high fever and cerebellar signs
Muccio C, D’Arco F et al
2014
39. Case : 7 y, intractable vomiting. MRI shows brainstem
lesion. Consideration for proton therapy
Biopsy?
Piloid gliosis, a type of chronic gliosis characterized
by […] varying degrees of hypercellularity and glial
atypia and associated with Rosenthal fibers, may be
very difficult to distinguish from a monomorphous
densely fibrillated PA.
-Collins et al Acta Neuropathol 2015
40. “Given the radiographic findings in the
setting of a prolonged clinical course
and near normal neurologic
examination, a diagnosis of low grade
glioma was considered. However, the
unusually symmetric appearance of
the lesion prompted other
“mutation analysis of the glial fibrillary
acidic protein (GFAP) gene mutation
was performed and ultimately revealed
a novel pathogenic GFAP gene
mutation”
41. Case : 7 y, mulifocal seizures
TSC !
• Cerebellar tubers : 1/3 cases of TSC
• Wedge shaped and folia distortion
• Enhancement : 30%
• Retraction of the cerebellar margin : 75%
• 20% increase in size and enhancement
overtime
Daghistani R, Rutka J, Widjaja E. 2015
42. Case : 15 y, 2 wks history of fever, low back pain and focal seizures
I am sure
these are
metastases
!
TBC !
43. Companion Case : child from Egypt, ongoing treatment for TBC
Diffuse leptomeningeal glioneuronal tumor
44. Case : 2 y, perinatal history of difficulty in swallowing
Briguglio M, Pinelli L et al 2014
Pontine
Tegmenta
l Cap
Dysplasia
45. WHO CNS 2016: A couple of tips…
Removal of the term primitive neuroectodermal
tumor or PNET: if C19MC- altered pathologist
call them ETMR
We should call them: “in keeping with embryonal
tumour”
Removal of the term Gliomatosi Cerebri (no
longer an entity)
We still use as a descriptive term representing
a growth pattern found in many gliomas.
46. Take Home Messages
New tumor classification including
histological and molecular data
Imaging can be used as a surrogate for
molecular diagnosis
Location – location –location ! (…but not
only)
Clinical context and careful analysis of image
characteristics helps in DDX with tumor-like
lesions
Same image characteristics…. What about the location? Different right? These are exactly the same tumour.
Despite similar location and appearances they are completely different
different location…. Same imaging characteristics …they are in the same moment the same entity (medulloblastoma) and completeyl different tumors (two different subgroup with different prognosis)
These examples are to show that in the last few years the classification of brain tumours become much more complicated buth also more precise, and you need to read papers on the new classification to have an overview.
Let’s start with cerebellar embryonal tumours
CT findings: Hyperdense mass in the posterior fossa (often in fourth ventricle), due to high cellularity (e-Figure 1). Possible presence of calcification/haemorrhages (1/5 of the cases) and small cystic/necrotic areas (up to half of the cases). Often associated with hydrocephalus
Typical appearances in T2 (hypo) ADC (low values- restriction ) enhancement. We see something like that in the child and we think of Medulloblastoma… but the thinks are not so easy.
4 groups with different demographics, histology , progonsis and genetics …now can we distinguish groups using images…maybe yes…let’s start with something easy.
As you can see an histological variant (desmoplastic / nodular) is always SHH subtypes so when we have typical nodular/desmoplastic appearance we are sure that this is a SHH….meaning good prognosis in infant and intermediate in older children…
Remeber not all the SHH have nodular/desmoplastic appearance, but it is also peripheral
different location…. Same imaging characteristics …they are in the same moment the same entity (medulloblastoma) and completeyl different tumors (two different subgroup with different prognosis)
Why only 2/3 cases? Red: EGL
Similar location but more heterogeneoity in comparison to WNT
Despite similar location and appearances they are completely different
Descrizione delle immagini
Both are H3 K27 mutant, again is important location but the focus is not supra , infratentorial or brain vs spine but more midline vs off-midline
We are not dealing with only one tumour this is just the tip of the iceberg
stregithforward
In questo caso le caratteristice di impregnazione , il poco effetto massa in confronto alla enorme
abscess
Alexander: c’e simmetria e non tanto effetto massa della lesione (nonostante enhancement). La testa del bambino e’ grande.. A volte anche una biopsia puo essere problematica ....
Vomiting!!
Tubero sclerosis cerebellar enhancement , Dale, Samuel
893205 she happened to do a plain film pre op : «There are multiple centrilobular lung parenchymal nodules with extensive infiltrate in the dependent pulmonary lobes tending to confluence in the dependent lung in keeping with haematogenous (miliary) infection. There is bilateral bibasal pleural change, in keeping with either pleural thickening or pleural fluid. There is a large pericardial fluid collection. The oesophagus is intimately involved with the para vertebral soft tissue mass and it would be important to assess the swallowing mechanism in this patient.”
The same as disseminated oligodendroglial-like leptomeningeal tumor of childhood