0:01

I'd like to finish up this brief pediatric section

0:04

with just a few comments about non glioma tumors

0:09

that are highlighted in the 2016

0:13

and 2021 revisions

0:16

of the WHO classification of tumors.

0:20

So with regard to medulloblastomas, remember

0:23

that we have now separated these into four different

0:27

molecular genetic types

0:29

and those types include the WNT, um,

0:34

Sonic Hedgehog type three and type four tumors.

0:38

And there are some imaging features

0:41

that suggest the wing type and the um, sonic hedgehog

0:45

and the type three and type four.

0:47

So those medulloblastomas that are off midline

0:51

and can actually be extra axial in the cerebellar

0:54

pontin angle cistern.

0:56

That is the imaging appearance of the WNT type

1:00

of medulloblastoma.

1:02

Used to be that some of these were called desmoplastic

1:05

medulloblastomas, that was back in the histologic days way

1:08

back in, you know, dinosaur era Sonic Hedgehog

1:12

is a tumor which is in the hemisphere again in the

1:16

periphery, but not necessarily extra axial.

1:19

The way the WNT may be,

1:22

it's multinodular typically enhances.

1:25

So these hemispheric mesoblast stomas tend

1:29

to be the s shh variety.

1:31

Then we have two types that are in the midline,

1:34

which is the more classic appearance of medulloblastomas.

1:37

In fact, type three and type four are more common than the

1:41

WNT and SHH varieties of mesoblast.

1:45

So type three is a midline lesion as we typically expect

1:49

with medulloblastomas potentially off the

1:52

inferior superior medullary vem, it enhances.

1:55

Whereas type four is one that is in the midline,

2:00

but in general does not enhance.

2:02

So based on the imaging features, we could predict which

2:06

of these is the wing type versus sonic hedgehog versus type

2:09

three versus type four.

2:11

Not a hundred percent, but not bad actually.

2:15

So that's somewhat reassuring.

2:18

Similarly, we have different classifications

2:20

of the appendamoma.

2:21

Now remember the appendamoma,

2:23

while I'm putting them in a pediatric category here, uh,

2:27

many of these appendamoma occur in adults

2:31

and remember that we have a sort of a different appearance

2:34

of appendamoma is in the super tentorial space versus those

2:38

that are in the posterior fossa.

2:41

In the super tentorial space,

2:42

they usually are intraparenchymal,

2:45

not necessarily in the ventricle.

2:47

You have some in the ventricles,

2:48

but more commonly super tentorial adult

2:52

appendamoma are in the parenchyma

2:55

and they are characterized by this

2:58

ZFTA relay fusion genetic profile.

3:03

It's a very aggressive profile.

3:06

It's a tumor that often recurs

3:08

and when it recurs, it may recur in the subarachnoid space

3:12

or along the Dora

3:13

and you know, can be a very aggressive uh, tumor.

3:18

So that is one of the genetic markers

3:21

for the super Tentorial Intraparenchymal Appendamoma.

3:26

The posterior fossa appendamoma are those

3:29

that we see more commonly in the children.

3:31

So back to the pediatric age group,

3:34

and there are two different types.

3:37

PF, A and PFB

3:39

and PF, let's just say refers to posterior fossa.

3:43

And with the A type Sumi CHA uses the mnemonic

3:47

that the A refers to asymmetrical.

3:50

Those are usually tumors

3:52

that are gonna be growing out the frame of lushka

3:54

and they aggressively invade the subarachnoid space.

3:58

They have an a awful prognosis

4:01

and they tend to occur in infants.

4:05

Those that are in the PFB category

4:08

are the more typical benign appearing append omas

4:11

that we hope for that are central in the fourth ventricle.

4:16

They have a ball shaped as well-defined as opposed

4:19

to ill-defined in PFA and they have a much better prognosis.

4:24

And while these can occur in children,

4:26

they may also be the variety

4:27

that we see in the posterior fossa in adults.

4:30

So I just wanted to round out our discussion

4:34

of pediatric brain tumors with a little snippet here

4:39

about non gliomas tumors, those being the myoblasts

4:43

and the pomas.

4:44

I hope that's helpful for you. Thank you for your attention.