Sheet 8

Question 1

What are the 3 types of gliomas?

Answer 1

1) Astrocytomas
2) Oligodendrogliomas
3) Ependymoma

Question 2

Oligodendrogliomas account for -% of gliomas.

Answer 2

5-15%

Question 3

Oligodendrogliomas are diagnosed at which ages?

Answer 3

40-50

Question 4

Where are oligodendrogliomas located?

Answer 4

Mostly in the cerebral hemispheres, mainly in the frontal or temporal lobes, white matter.

Question 5

What is diagnostic for oligodendrogliomas?

Answer 5

The presence of IDH mutation AND 1p & 19q co-deletion

Question 6

How do we treat oligodendrogliomas?

Answer 6

With a combination of surgery, chemotherapy, and radiotherapy

Question 7

What is the average survival rate of a grade 2 oligodendrogliomas?

Answer 7

10-20 years (because of infiltration)

Question 8

What is the average survival rate of a grade 3 oligodendrogliomas?

Answer 8

5-10 years (because of anaplastic features)

Question 9

Which grades of oligodendrogliomas don’t exist?

Answer 9

1 and 4

Question 10

Which has a better prognosis(!):

Grade 3 astrocytoma or grade 3 oligodendroglioma?

Answer 10

Grade 3 oligodendroglioma

Question 11

What are the characteristics of grade 2 oligodendrogliomas?

Answer 11

1) Infiltrative tumors
2) +/- cysts
3) Focal hemorrhage
4) Calcification

Question 12

If we see calcifications with a diffuse infiltrating tumor in the radiograph, which tumor is it most likely to be?

Answer 12

Oligodendroglioma

Question 13

What are the histological characteristics of grade 2 oligodendrogliomas?

Answer 13

1) Sheets of regular cells with spherical nuclei containing finely granular chromatin
2) The nuclei are surrounded by a clear perinuclear halo of cytoplasm (Fried-egg appearance).
3) Delicate network of anastomosing capillaries “chicken-wire”.
4) Calcification in 90% of tumors.
5) Low mitotic activity
6) No spontaneous necrosis.
7) No microvascular proliferation.

Question 14

What are the histological characteristics of grade 3 oligodendrogliomas?

Answer 14

1) Increased cellularity
2) Easily identifiable mitotic figures
3) Microvascular proliferation, ± necrosis

Question 15

Where do ependymomas arise?

Answer 15

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

Question 16

Where are ependymomas located?

Answer 16

1) Posterior fossa (60%)
2) Supratentorial (30%)
3) Spinal (10%)

Question 17

At which age do ependymomas appear?

Answer 17

1) In the first 2 decades of life; near the 4th ventricle (posterior fossa)
2) In adults, the spinal cord and supratentorial ependymomas occur with almost equal frequency

Question 18

Which clinical outcome is better for completely resected ependymomas:
Supratentorial & spinal
ependymomas or posterior fossa ependymomas?

Answer 18

Supratentorial & spinal

ependymomas

Question 19

What is the morphology of ependymomas?

Answer 19

Composed of uniform small cells with round to oval nuclei and granular chromatin in a fibrillary matrix and characterized by:

1) Rosette formation
2) Low cell density and a low mitotic count
3) Cilia and microvilli are seen on ultrastructural examination

Question 20

What are the 2 types of rosettes?

Answer 20

1) Ependymal rosettes: diagnostic hallmark of ependymoma (25%)
2) Perivascular pseudorosettes: not specific for ependymoma.

Question 21

What are rosettes?

Answer 21

Tumor cells arranged like a

circle around a central structure

Question 22

What are ependymal rosettes?

Answer 22

Tumor cells arranged around central canal or lumen that resemble the embryologic ependymal canal, with long, delicate processes extending into a lumen.

Question 23

What are perivascular pseudorosettes?

Answer 23

Composed of tumor cells radially arranged around vessels with an intervening anucleated zone containing thin ependymal processes.

Question 24

What is the morphology of anaplastic ependymomas?

Answer 24

1) Increased cell density
2) High mitotic rates
3) Necrosis
4) Microvascular proliferation
5) Less evident ependymal
differentiation

Question 25

What are the neuronal and glioneuronal tumors?

Answer 25

1) Central neurocytoma 2) Ganglioglioma 3) Dysembryoplastic neuroepithelial tumor (DNT or DNET)

Question 26

What is the shared feature of all neuronal and glioneuronal tumors?

Answer 26

All of them show neuronal differentiation = when you stain them with immune stains for neurons, they are going to be positive (synaptophysin positive and neurofilament positive)

Question 27

What is the most common presentation of neuronal and glioneuronal tumors?

Answer 27

Seizures

Question 28

Which are more frequent: | Neuronal tumors or Gliomas?

Answer 28

Gliomas

Question 29

What are neuronal tumors composed of?

Answer 29

Cells with neuronal characteristics and express neuronal markers, such as synaptophysin and neurofilaments.

Question 30

What is a Central neurocytoma, WHO grade 2?

Answer 30

``` Low-grade neuronal tumor within and adjacent to the lateral ventricle(s) and/or the third ventricle affecting young adults (NO glial component). ```

Question 31

What is a Ganglioglioma, WHO grade 1?

Answer 31

Well differentiated glioneuronal tumor affecting children and young adults. composed of a mixture of neoplastic ganglion and glial cells, most commonly in the temporal lobe.

Question 32

What is a Dysembryoplastic neuroepithelial tumor (DNT), WHO grade 1?

Answer 32

Low-grade (well differentiated) glioneuronal tumor affecting the cerebral cortex of children and young adults most commonly in the superficial temporal lobe.

Question 33

What are the 3 oncogenic pathways of medullablastomas?

Answer 33

1) WNT pathway activation 2) Hedgehog pathway activation 3) MYC overexpression

Question 34

What is the most common CNS neoplasm in immunosuppressed individuals?

Answer 34

Primary CNS Lymphoma

Question 35

What is the most common subtype of Primary CNS Lymphoma?

Answer 35

Diffuse large B-cell lymphomas

Question 36

How does Primary CNS Lymphoma present as?

Answer 36

1) Multiple tumor nodules within the brain parenchyma 2) Well-defined 3) Not as discrete as metastases

Question 37

What is the most common primary CNS germ cell tumor?

Answer 37

Germinoma, testicular seminoma

Question 38

Where are primary brain germ cell tumors found?

Answer 38

Along the midline, pineal and suprasellar regions