Central Nervous System Tumors in Children Flashcards

Question 1

Q

The etiology of pediatric CNS tumors remains largely unknown. Only 2% to
5% can be ascribed to a known genetic predisposition.

Enumerate the conditions with genetic predisposition to develop CNS tumors in children.

Answer

A

NF1
NF2
nevoid basal cell (Gorlin’s) syndrome

familial adenomatous polyposis

Li Fraumeni syndrome.

Question 2

Q

In pediatric CSI, what should be the lower limit of the spine CTV?

Answer

A

The lower limit of the CTV for the spine field should be determined
using MRI.

The lower border of the spinal CTV should include the lower border
of the thecal sac, which can be as high as L5 or as low as S3

Question 3

Q

Give a possible solution to improve the outcomes encountered with the following scenarios/problem in CSI:

Field matching over cervical spine/risk of over- or underdosage

Answer

A

Angle brain fields

use half-beam block for brain fields

use couch rotation or match line wedge

Question 4

Q

Give a possible solution to improve the outcomes encountered with the following scenarios/problem in CSI:

Inhomogeneity along spinal axis

Answer

A

Use compensator, MLC

Question 5

Q

Give a possible solution to improve the outcomes encountered with the following scenarios/problem in CSI:

Irradiation of normal tissues - mandible teeth

Answer

A

Neck extension

Question 6

Q

Give a possible solution to improve the outcomes encountered with the following scenarios/problem in CSI:

Irradiation of normal tissues - thyroid

Answer

A

Care with level of junction

Question 7

Q

Give a possible solution to improve the outcomes encountered with the following scenarios/problem in CSI:

Irradiation of normal tissues - heart

Answer

A

Use lower junction

Question 8

Q

Give a possible solution to improve the outcomes encountered with the following scenarios/problem in CSI:

Irradiation of normal tissues - GI tract

Answer

A

Care with width of spine field

Use protons, IMRT, electrons

Question 9

Q

Give a possible solution to improve the outcomes encountered with the following scenarios/problem in CSI:

Irradiation of normal tissues - gonads

Answer

A

Care with lower limit and width of spine field

Use protons, IMRT, electrons

Question 10

Q

Central Nervous System Tumors in Children

LGA’s account to a third to half of all pediatric CNS tumors.

TRUE or FALSE?

Question 11

Q

Central Nervous System Tumors in Children

Most pediatric CNS tumors are supratentorial.

TRUE or FALSE?

Answer

A

False

Infratentorial

Question 12

Q

Central Nervous System Tumors in Children

What is the most common type of astrocytoma in children?

Answer

A

Pilocytic astroctyoma

Question 13

Q

Central Nervous System Tumors in Children

Describe the histology/pathologic picture of pilocytic astrocytoma.

Answer

A

well circumscribed with an associated cystic component.

biphasic pattern with a varying proportion of compacted bipolar cells with Rosenthal fibers and loose-textured multipolar cells with microcysts and granular bodies.

Rare mitoses, occasional hyperchromatic nuclei, microvascular proliferation, and even infiltration of meninges.

KIAA1549-BRAF fusions have been identified in 75% of patients
with PA using an RT-PCR assay from FFPE tissue.

Question 14

Q

Central Nervous System Tumors in Children

What variant of pilocytic astrocytoma, first described in infants and children with
chiasmatic/hypothalamic tumors, appears to be associated with more aggressive
behavior that may include leptomeningeal seeding?

Answer

A

pilomyxoid astrocytoma

Question 15

Q

Central Nervous System Tumors in Children

Where are the two most common locations of pilocytic astrocytoma, wherein they account for almost all LGAs in those areas?

Answer

A

cerebellum

anterior optic pathway

Question 16

Q

Central Nervous System Tumors in Children

Where are the two most common locations of diffuse astrocytoma?

Answer

A

cerebral hemispheres

pons

Question 17

Q

Central Nervous System Tumors in Children

Describe the histology/pathologic picture of diffuse astrocytoma.

Answer

A

well-differentiated fibrillary or gemistocytic neoplastic astrocytes on a background of loosely structured, often microcystic, tumor matrix.

moderately increased cellularity.

nuclear atypia is a diagnostic criterion
(mitotic activity, necrosis, and proliferation are absent)

low Ki-67 and MIB-1 labeling indices.

Question 18

Q

Central Nervous System Tumors in Children

What is the syndrome commonly manifested by young children with chiasmatic/hypothalamic tumors that present with the ff:

emaciation with loss of subcutaneous fat despite normal or increased appetite, alert appearance, increased vigor and euphoria, pallor without anemia, and nystagmoid movements of the eyes

Answer

A

diencephalic syndrome

Question 19

Q

Central Nervous System Tumors in Children

Neuroimaging findings in pilocytic astrocytoma

Answer

A

well circumscribed with an associated cystic component.

There is usually little edema or mass effect.
The solid component enhances brightly and uniformly with contrast material.

Question 20

Q

Central Nervous System Tumors in Children

Diffuse or fibrillary astrocytomas are usually not well seen on
nonenhanced CT or MRI and usually show little enhancement with contrast
material.

What sequences usually best demonstrate the extent of disease?

Answer

A

T2-weighted
or
FLAIR

Question 21

Q

Central Nervous System Tumors in Children

For pilocytic astrocytomas and diffuse or fibrillary LGAs, postoperative adjuvant therapy is not indicated after complete resection.

TRUE or FALSE?

Question 22

Q

Central Nervous System Tumors in Children

For pilocytic astrocytomas and diffuse or fibrillary LGAs, postoperative adjuvant therapy observation can be an option.

How frequent is surveillance MRI performed?

Answer

A

every 6 months for 3 years.

Question 23

Q

Central Nervous System Tumors in Children

For pilocytic astrocytomas and diffuse or fibrillary LGAs, postoperative adjuvant therapy observation can be an option.

What are the options at the time of progression?

Answer

A

Second surgical resection.

if not resectable RT (or chemotherapy: for children ≤10 and children of all ages with NF1)

Question 24

Q

Central Nervous System Tumors in Children

What are the indications for RT in LGA?

Answer

A

following incomplete resection in situations when tumor progression would compromise neurologic function (e.g., “threat to vision”)

patients with progressive and/or symptomatic disease that is unresectable.

Question 25

Q

Central Nervous System Tumors in Children

What is the GTV in LGA?

Answer

A

all disease seen on MRI just prior to RT

Question 26

Q

Central Nervous System Tumors in Children

What is the CTV for fibrillary astrocytoma?

Answer

A

GTV as seen on T2 weighted or FLAIR

+ 1 to 1.5 cm margins

Question 27

Q

Central Nervous System Tumors in Children

What is the CTV for pilocytic astrocytoma?

Answer

A

GTV as seen on T1-W with contrast + 0 to 1 cm.

GTV=CTV is acceptable.

Question 28

Q

Central Nervous System Tumors in Children

What is the standard RT total dose?

Answer

A

50 to 54 Gy

Evidence for a dose–response correlation in LGAs in children is scant. Although
the European and North American studies that randomized adult patients with
LGAs between low dose (45 and 50.4 Gy, respectively) and high dose (59.4 and
64.8 Gy, respectively) radiotherapy failed to demonstrate any advantage for the
higher dose, it may be unwise to extrapolate that in children doses of 45 to 50
Gy are as effective as the higher doses of 54 to 55 Gy that until now have
constituted standard practice. There are biologic differences between LGAs in
children and in adults. As well, children who have progressed on chemotherapy
may have tumors that are less sensitive. For now, the recommendation for
children with LGAs would be a “standard” dose of 50 to 54 Gy depending on the
age of the child and the location of the tumor and its relationship to critical
normal structures such as the optic chiasm.

Question 29

Q

Central Nervous System Tumors in Children

Is SRS an option for LGA?

Answer

A

yes.
may be considered for pilocytic but not for diffuse.

10 to 20 Gy to the periphery

Question 30

Q

Central Nervous System Tumors in Children

What are the histopathologic features of anaplastic astrocytoma?

Answer

A

nuclear atypia
increased cellularity
significant proliferative activity.

Question 31

Q

Central Nervous System Tumors in Children

What are the histopathologic features of glioblastoma multiforme?

Answer

A

mitotic activity
nuclear atypia
microvascular proliferation
necrosis
cellular pleomorphism
vascular thrombosis

Question 32

Q

Central Nervous System Tumors in Children

Where is the most common locations of HGA in children?

Answer

A

cerebral hemispheres (2/3)

remainder equally divided between deep midline structures and cerebellum.

Question 33

Q

Central Nervous System Tumors in Children

What is the standard of care for HGAs?

Answer

A

maximal safe resection + PORT

Question 34

Q

Central Nervous System Tumors in Children

GTV and CTV in HGAs

Answer

A

GTV = tumor plus any T2-weighted MRI abnormality.

CTV = GTV + 1.5 cm

Question 35

Q

Central Nervous System Tumors in Children

RT dose (HGA)

Answer

A

59 to 60 Gy

may consider volume reduction to CTV1cm after 50 to 54 Gy

Question 36

Q

Central Nervous System Tumors in Children

Children younger than age 3 with HGAs fare better than older children

TRUE or FALSE?

Answer

A

True

In contrast to most other tumor types, children
younger than age 3 with HGAs fare better than older children, with overall
survival at 3 to 5 years in the 33% to 50% range in the North American and
United Kingdom Children’s Cancer Study Group/International Paediatric
Oncology Society (UKCCSG/SIOP) baby studies.

The prognosis may be
even better for children younger than age 1.

Question 37

Q

Central Nervous System Tumors in Children

p53 overexpression and a high MIB-1 labeling index appears to be a favorable prognostic factor.

TRUE or FALSE?

Answer

A

False

p53 overexpression and a
high MIB-1 labeling index appear to identify patients with a particularly adverse
prognosis

Question 38

Q

Central Nervous System Tumors in Children

What are the three types of optic pathway gliomas?

Answer

A

anterior tumors

confined to optic nerve
optic chiasm +/- nerve

posterior tumors
-chiasmatic/hypothalamic

Question 39

Q

Central Nervous System Tumors in Children

One third of optic pathway gliomas are associated with what genetic condition, where bilateral involvement of the optic nerves is pathognomonic?

Question 40

Q

Central Nervous System Tumors in Children

What is the usual presentation of a patient with optic nerve glioma without NF-1?

Answer

A

proptosis, long-standing

Question 41

Q

Central Nervous System Tumors in Children

MRI findings in optic nerve gliomas?

Answer

A

small, well-circumscribed, with bright enhancement typical for pilocytic astroctyoma.

Question 42

Q

Central Nervous System Tumors in Children

in optic nerve gliomas “and” optic chiasm gliomas, biopsy is necessary to make a diagnosis.

TRUE or FALSE?

Question 43

Q

Central Nervous System Tumors in Children

What is the preferred treatment for optic nerve glioma patients predicted to not have functional vision?

Answer

A

surgical resection

Question 44

Q

Central Nervous System Tumors in Children

What is the preferred treatment for optic nerve glioma patients with functional vision for patients with NF-1?

Answer

A

chemotherapy

Question 45

Q

Central Nervous System Tumors in Children

What is the preferred treatment for optic nerve glioma patients with functional vision for infants and patients up to age 5?

Answer

A

chemotherapy

Question 46

Q

Central Nervous System Tumors in Children

What is the preferred treatment for optic nerve glioma patients with functional vision for older patients?

Answer

A

chemotherapy.

RT may be considered.

Question 47

Q

Central Nervous System Tumors in Children

MRI findings in optic chiasm gliomas?

Answer

A

small and well circumscribed and enhance uniformly and brightly with contrast
material, suggestive of pilocytic histology

Question 48

Q

Central Nervous System Tumors in Children

What is the appropriate initial step in the management of chiasmatic gliomas in patients with NF-1?

Answer

A

surveillance

Question 49

Q

Central Nervous System Tumors in Children

What is the role of RT in the management of chiasmatic gliomas?

Answer

A

reserved for
salvage after chemotherapy

definitive treatment of older children without
NF-1

Question 50

Q

Central Nervous System Tumors in Children

What is the most common optic pathway glioma?

Answer

A

posterior tumors
-chiasmatic/hypothalamic

(70%)

Question 51

Q

Central Nervous System Tumors in Children

What is the role of RT in the management of posterior optic pathway gliomas?

Answer

A

progressive disease on chemotherapy
for children younger than 10

progressive disease at diagnosis or after
surgery for older patients

Question 52

Q

Central Nervous System Tumors in Children

RT dose, posterior optic pathway gliomas

younger children ≤5 years

Answer

A

45 to 50 Gy

Question 53

Q

Central Nervous System Tumors in Children

RT dose, posterior optic pathway gliomas

older than 5 years

Answer

A

50 to 54 Gy

Question 54

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

MRI findings in focal tumors

Answer

A

well circumscribed

without evidence of infiltration and edema

may be cystic

uniform bright enhancement with contrast material, which correlates with pilocytic histology

absence of peritumoral hypodensity

Question 55

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

Most common location of focal tumors

Answer

A

midbrain and medulla

Question 56

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

treatment of choice for focal tumors

Question 57

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

role of RT in focal tumors

Answer

A

same as in other LGAs

Question 58

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

Most common location of dorsal exophytic tumors

Answer

A

floor of the fourth ventricle

Question 59

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

MRI findings in dorsal exophytic tumors

Answer

A

sharply delineated

hypointense on T1W
hyperintense on T2
enhance uniformly

Question 60

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

treatment of choice for dorsal exophytic tumors

Answer

A

surgery

maximal safe resection

Question 61

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

treatment of choice for dorsal exophytic tumors with residual after surgery

Answer

A

observation.

routine RT is not indicated.

Question 62

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

role of RT in dorsal exophytic tumors

Answer

A

high-grade lesion

progressive disease (<9 months postop)

inoperable disease

Question 63

Q

Central Nervous System Tumors in Children
Brainstem Gliomas

treatment of choice for dorsal exophytic tumors with later recurrence postop

Answer

A

second surgery

Question 64

Q

Central Nervous System Tumors in Children
DIPG

DIPG accounts for the majority of brainstem gliomas.

TRUE or FALSE?

Answer

A

True

70% to 80%

Answer 60

A

On CT, DIPGs are isodense or hypodense, with little enhancement after contrast
injection, similar to diffuse fibrillary astrocytomas at other sites. They are best
seen on T2-weighted or FLAIR MRI. The presence of ring enhancement is
suggestive of high-grade histology.

Answer 61

A

GTV = T2W or FLAIR abnormality

CTV 1-1.5 cm

Answer 62

A

39/3/13

45/3/15

Answer 63

A

solid portion (including intratumoral cysts)
margin of 1 to 1.5 cm

(at least 1.5 for HGAs)

Answer 64

A

50.4/1.8/28

same for both LGA and HGAs, unlike in adults where HGAs are treated to 54

Answer 65

A

filum terminale

Answer 66

A

back pain

Answer 67

A

macroscopic residual + cc margin 1.5 cm (or one vertebral body)

Answer 68

A

CSI curative intent + boost to primary site

Answer 69

A

ependymal lining of the fourth ventricle

Answer 70

A

(a) patients with ependymoma of the spinal cord who have undergone complete resection for whom disease-free survival in contemporary series approaches 100%

and (b) selected patients
with supratentorial ependymoma, such as those with intraventricular tumors or
with extraventricular tumors that are solid and located in noneloquent areas and
can be resected with a wider margin.

Answer 71

A

The GTV is a composite of the
tumor bed, including any extension caudal to the foramen magnum and taking
into account any anatomic shifts because of surgery plus any residual tumor

CTV 1 cm (SJCRH)
CTV 0.5 (COG)

Answer 72

A

54 to 59.4

54 if limited by OARs

Answer 73

A

By definition, an anaplastic ependymoma is a malignant glioma of ependymal
differentiation that is characterized by high mitotic activity, often accompanied
by microvascular proliferation and pseudopalisading necrosis. There are no
histopathologic features that can reliably differentiate anaplastic ependymomas
from the more slowly growing and more favorable ependymomas

Answer 74

A

tumor bed and any
macroscopic residual disease with a margin for the CTV of 1 cm

dose similar to WHO grade II

CSI was abandoned as standard of care

Answer 75

A

Rosette formation

from adult CNS chapter

Answer 76

A

(from adult CNS chapter)

Historically, for posterior fossa tumors, the entire posterior fossa has been irradiated.
However, Paulino has shown that the pattern of failure to be “local,” i.e., within the tumor bed itself.

In 9 patients who received RT to the tumor bed + a 2 cm margin, the two failures in this group were within the tumor bed (i.e., there were no failures within the PF outside the tumor bed).

Answer 77

A

Myxopapillary

Answer 78

A

when the cauda is involved

taken from spinal chapter

Answer 79

A

Papilloma (CPP) (WHO I)

Answer 80

A

atypical (WHO II)

Answer 81

A

delicate fibrovascular
connective tissue fronds covered by a single layer of uniform cuboidal columnar
epithelial cells with round or oval basally situated monomorphic nuclei.

low mitotic activity

Answer 82

A

carcinoma (CPC) (WHO III)

Answer 83

A

lateral ventricles

causing CSF flow obstruction.

Answer 84

A

usually hyperdense,

contrast-enhancing masses

Answer 85

A

ganglioglioma and central neurocytoma

Answer 86

A

Parinaud syndrome

Answer 87

A

The target volume is local, consisting of macroscopic residual disease with a margin for the CTV of 1 cm, and the dose, 50 to 55 Gy over 6 weeks.

Answer 88

A

enlarging head circumference

signs of short duration increased ICP.

Answer 89

A

CSI and chemotherapy

Answer 90

A

Medulloblastoma

Answer 91

A

WNT-activated

SHH (TP53 mutant/wild tyep)

non WNT/non-SHH (3)

non WNT/non-SHH (4)

Answer 92

A

<1.5 cm2 residual on MRI 48-72 hours post op.

no evidence of CSF dissemination

Answer 93

A

prior to surgery or at least 2 weeks post-op to avoid artifacts

Answer 94

A

CSI 23.4 Gy with a boost to the tumor bed to a total dose of 54.0 Gy, followed by eight cycles of chemotherapy with vincristine, CCNU, and cisplatin.

Answer 95

A

deletion and/or mutation of the INI1 locus on chromosome 22

Answer 96

A

Pineal gland

suprasellar region

Answer 97

A

germinoma

Answer 98

A

*obstruction to csf flow

signs of increased ICP
hydrocephalus
parinaud syndrome

Answer 99

A

long history of neuroendocrine deficits

later, increased ICP

Answer 100

A

pure germinomas

Answer 101

A

choriocarcinoma

Answer 102

A

yolk-sac tumor

Answer 103

A

choriocarcinoma

Answer 104

A

whole brain (whole ventricular RT) + margin with concurrent platinum based chemotherapy.

Answer 105

A

There is less controversy now with regard to the radiotherapy dose and dosefractionation
schedule for germinoma. Results are excellent with a CSI dose as
low as 21 Gy even in patients with leptomeningeal spread. The total dose to the
primary site has typically been 40 to 45 Gy but probably can be safely reduced
to 30 Gy or even to 24 Gy in patients treated with a combined
chemotherapy–radiotherapy regimen who have had a complete response to
chemotherapy. Finally, because germinoma is a very radiosensitive tumor, a
fraction size of 1.5 Gy can be used, which, in theory, further reduces the risk of
injury to normal structures.

Answer 106

A

The usual dose to the whole ventricle volume or CSI is 30 to 36 Gy and to the primary site, 54 Gy. Patients who have less than a complete response to chemotherapy fare poorly.

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Central Nervous System Tumors in Children Flashcards

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