Glioblatomas are either: - PowerPoint Presentation

Slide1

Glioblatomas

are either:

Primary

- The patients develop it from the start

Is the most common type of

glioblastoma

2. Secondary

Progress from lower grades

Note :

Once the

histologic

features of

glioblastoma

appear, the prognosis is very poor; with treatment( resection , radiotherapy , and chemotherapy), the median survival is only 15 months

Slide2

Note:

Infatile

pilocytic

astrocytoma

is called

pilomyxoid

astrocytoma

and it is grade II typically located in the

hypothalamus

Morphology of

pilocytic

astrocytoma

Gross

:

Well circumscribed

Is often cystic, with a mural nodule in the wall of the cyst

Slide3

Tumors that appear on MRI as cyst containing a nodule are:

Pilocytic

astrocytoma

Ganglioglioma

Pleomorphic

Xantho

astrocytoma

Slide4

Microscopically,

pilocytic

astrocytoma

- The

tumor

shows

Hypercellular

areas composed of bipolar

astrocytes

with

with

long, thin "

hairlike

" processes that are GFAP positive

Hypocellular

areas formed of

microcysts

.

c. Rosenthal

fibers

d.

Eosinophilic

granular bodies,

e. Necrosis and mitoses are absent

.

Genetically

Pilocytic

astrocytomas

don’t show mutations in IDH1 and IDH2

Slide5

Pilocytic astrocytoma

Slide6

Pilocytic astrocytoma

Slide7

B

.

Oligodendroglioma

- These

tumors

constitute about 5% to 15% of

gliomas

- Are most common in the fourth and fifth decades.

- Patients may have had several years of neurologic complaints, often including seizures.

- The lesions are found mostly in the cerebral hemispheres,

mainly in the frontal or temporal lobes

- Patients have better prognosis than

astrocytomas

of similar grade

Slide8

Morphology

Gross

Are infiltrative

tumors

may show cysts,

hemorrhage

, and calcification.

Note: Is the most common CNS

tumor

showing calcification

On microscopic examination

,

1. Grade II

oligodendroglioma

:

Is composed of sheets of regular cells with spherical nuclei containing fine chromatin

The nuclei are surrounded by a clear halo of cytoplasm

Slide9

Grade II oligodendroglioma

Slide10

-

The

tumor

typically contains a delicate network of

anastomosing

capillaries.

- Calcification, present in as many as 90% of these

tumors

,

2. Grade III

anaplastic

oligodendroglioma

Characterized by:

Significant mitotic activity(minimum criterion)

And/or

microvascular

proliferation

And/ or

necrosis(geographic or

pseudopalisading

)

Slide11

- Treatment with surgery,

chemtherapy

, and radiotherapy yield an average survival of 10-20 years for grade II and 5-10 years for grade III.

- The most common genetic findings in

oligodendrogliomas

is 1p19q

codeletion

-

Tumors

with just those specific changes have a consistent and long-lasting response to chemotherapy

Slide12

C.

Ependymoma

-

Ependymomas

most often arise next to the

ependyma

-lined ventricular system, including the central canal of the spinal cord.

In

the first two decades of

life

a.

,

they typically

arise from floor of the fourth

ventricle

b. and

constitute 5% to 10% of the primary brain

tumors

in this age group.

In

adults

,

the spinal cord is their most common

location

; and

is considered as the most common type of

glioma

in the spinal cord in adults

Slide13

tumors

in this site (if multiple) are particularly frequent in the setting of

neurofibromatosis type 2

Notes

- May arise in the

supratentorial

region

- The clinical outcome for completely

resected

supratentorial

and spinal

ependymomas

is better than for those in the posterior

fossa

Slide14

Microscopically

:

1. Grade II

ependymomas

Are well circumscribed

gliomas

- Composed of cells with regular, round to oval nuclei

Between the nuclei there is a variably dense

fibrillary

background

Tumor

cells may form:

Round or elongated structures (

True

rosettes,

canals)

that resemble the embryologic

ependymal

canal with long, delicate processes extending into a lumen

Slide15

True Rosettes of ependymoma

Slide16

Are specific to

ependymoma

but are

infrequent

2

.

Perivascular

pseudo-rosettes

More frequently present

Not specific to

ependymomas

-

Tumor

cells are arranged around vessels with an intervening zone containing the

ependymal

processes

.

Slide17

Ependymoma

Slide18

Perivascular pseudo rosettes

Slide19

2.

Anaplastic

ependymomas

(grade III) show

:

Microvascular

proliferation

Pseudopalisading

necrosis

Note:- Presence of geographic necrosis can be seen in grade II

ependymomas

and

doesnt

upgrade

3.

Myxopapilllary

ependymoma

( grade I )

Arises in the

filum

terminale

and has good prognosis but tends to recur if not completely excised

Slide20

II.

Neuronal

Tumors

1. Central

neurocytoma

(grade II)

- Is a low-grade neuronal neoplasm

Found

within and adjacent to the ventricular system (most commonly

at the level of foramen of Munro)

2

.

Gangliogliomas

- Are

tumors

with a mixture of

glial

elements (looking like a low-grade

astrocytoma

) and mature-appearing neurons.

Most

of these

tumors

are

slowly

growing

,

- These lesions often present with seizures

Slide21

Embryonal

primitive

neoplasms

- The most common is the

medulloblastoma

,

accounting for 20% of

pediatric

brain

tumors

.

Medulloblastoma

(WHO grade IV)

occurs

predominantly in children

and

exclusively in the cerebellum.

-

The

tumor

is highly malignant,

The

prognosis for untreated patients is

dismal

- It is radiosensitive

- With total excision and radiation, the 5-year survival rate may be as high as 75%.

Slide22

.

-

Tumors

of similar histology can be found elsewhere in the nervous system (called CNS primitive

neuroectodermal

tumor

, or CNS PNET

)

Morphology

- In children,

medulloblastomas

are located in the midline of the cerebellum (

vermis

) but may extend to the surface of the

cerebellar

folia and involving the

leptomeninges

- Lateral

tumors

(in

cerebellar

hemispheres) occur more often in adults.

Slide23

Microscopically

a. Are extremely cellular, with sheets of

anaplastic

("small blue") cells

b. Individual

tumor

cells are small, with little cytoplasm and

hyperchromatic

nuclei;

Mitoses

are abundant.

May show Homer-

wright

rosettes

as evidence of neuronal differentiation

Slide24

Medulloblastoma

Slide25

medulloblastoma

Slide26

IV. Primary Central Nervous System Lymphoma

Accounts for 1% of intracranial

tumors

.

A-

It is the most common CNS neoplasm in

immunosuppressed

individuals (including transplant recipients and persons with AIDS); under these circumstances the CNS lymphomas are nearly all driven by Epstein-Barr

virus and show

necrosis

B. In

non-

immunosuppressed

populations, the age spectrum is relatively wide, with the incidence increasing after 60 years of age

;

- Most of these

tumors

are diffuse large B-cell

lymphomas

Slide27

- Regardless of the clinical context, primary brain lymphoma is an aggressive disease with relatively poor response to chemotherapy as compared with peripheral lymphomas

- Individuals with primary brain lymphoma often have multiple sites of

tumor

within the brain parenchyma;

-. Lymphoma arising outside the CNS rarely involves the brain parenchyma; when it does occur, there is usually

tumor

within the CSF and around

intradural

nerve roots

-

Slide28

V

. Germ cell tumors

- Primary brain germ-cell tumors occur

commonly

in:

A. Pineal region

B.

suprasellar

region

- 90% occur during the first two decades of life

- CNS involvement by a

gonadal

germ-cell tumor is not uncommon

Slide29

VI.

Meningiomas

:

- They occur in adults

- A

re

predominantly

benign tumors that arise from

arachnoid

cap cells and attached to the

dura

.

- May be found along any of the external surfaces of the brain as well as within the ventricular system, where they arise from the

arachnoid

cells of the choroid plexus.

- Clinically they either present with vague non-localizing symptoms, or with focal findings referable to compression of adjacent brain.

Slide30

- Although most

meningiomas

are easily separable from underlying brain, some may infiltrate the brain, a feature that is associated with an increased risk of recurrence

- The overall prognosis is determined by the location, surgical accessibility, and

histologic

grade.

- When a person has multiple

meningiomas,with

bilateral vestibular

schwannomas

or spinal

ependymoma

, the diagnosis of NF2 syndrome should be considered

Slide31

- About half of

meningiomas

not associated with NF2 have acquired loss-of-function mutations in the

NF2

tumor suppressor gene on the long arm of chromosome 22 .

- These mutations are found in all grades of

meningioma

,.

-

NF2

mutations are more common in tumors of certain patterns (fibroblastic, transitional,

psammomatous

).

Slide32

Gross-:

WHO grade I grow as well-defined

dura

-based masses that may compress the brain but do not invade it and

extension into the overlying bone may be present and does not upgrade the tumor to grade II.

Microscopic :

Oval cells with indistinct borders and

Intranuclear

pseudoinclusions

arranged in

syncytia

with

whorling

Slide33

Meningioma

Slide34

Meningeoma

Slide35

Grade I

No more than 3 MF/10HPF

2. Grade II

meningeoma

are recognized by either:

A. Mitotic figures of more than 3 but less than 20 per 10 HPF(high power fields)

B. Or presence of 3 of the following 5 atypical features

1. Small cells,

2. Prominent nucleoli ,

3. Sheeting

4.

Hypercellularity

,

5. Spontaneous necrosis not induced by

embolization

Slide36

C. Or Brain invasion

D. Clear or

chordoid

variants

- These tumors are more aggressive with a higher rate of recurrence and may require radiation therapy in addition to surgery

3.

Anaplastic

(malignant)

meningiomas

(WHO grade III)

- Are highly aggressive tumors characterized by either:

a. They resemble a high-grade sarcoma or carcinoma or melanoma

b. Or Mitotic figures of 20 or more per 10HPF(high power fields)

c. Papillary or

rhabdoid

variants

Slide37

VII. Metastatic Tumors

- The most common primary sites are lung, breast, skin (melanoma), kidney, and gastrointestinal tract-

- Metastases form sharply demarcated masses, often at the gray-white junction, and elicit marked edema

- The boundary between tumor and brain parenchyma is sharp at the microscopic level as well

Slide38

CNS

manifestaions

of Familial Tumor Syndromes

I. Tuberous Sclerosis :

- Is an

autosomal

dominant syndrome characterized by

a. The development of CNS

hamartomas

consist of: Cortical tubers which are associated with seizures and can be difficult to control with antiepileptic drugs.

b. Benign brain

neoplasms

such as

subependymal

giant cell

astrocytoma

and because of their proximity to the

Slide39

foramen of

Monro

, they present acutely with obstructive hydrocephalus, which requires surgical intervention

2

. v

on

Hippel-Lindau

Disease:

- An

autosomal

dominant

- The CNS tumor is

hemangioblastoma

(grade I)

Hemangioblastomas

insporadic

cases occur in the

cerebellar

hemispheres and spinal cord

In

v

on

Hippel-Lindau

Disease:

, tend to occur as multiple lesions

in the

spinal cord

Slide40

Paraneoplastic

syndromes affecting the brain

1.

Subacute

cerebellar

degeneration

- Resulting in ataxia, with destruction of Purkinje cells,

2. Limbic encephalitis

:

- Causing a

subacute

dementia,

-

Charcterized

by

perivascular

inflammatory cells, some neuronal loss, and

gliosis

, in the medial temporal lobe

Slide41

3.

Syndrome of rapid-onset psychosis, epilepsy, and coma

- Associated with ovarian

teratoma

and antibodies against the

N

-methyl-d-

aspartate

(NMDA) receptor