0:00

Now moving on to second type of tumor

0:03

that pediatric patients might get is the

0:05

diffuse midline glioma.

0:07

So these are tumors that are

0:10

disorders primarily of a histone.

0:13

And I think some of you know

0:14

that each human cell DNA is about 1.8 meters,

0:17

but thanks to histone, which winds down the, um,

0:22

DNA into 90 micrometers.

0:25

But you could see that if there is a histone related

0:29

abnormality, it could lead

0:30

to just devastating tumors like this,

0:33

particularly the histone H three

0:36

K 27 M locus tends to cause tumors of this

0:41

gigantic midline glioma.

0:43

So comes the name of diffuse midline glioma,

0:47

H three K 27 M alter.

0:49

So this is, um, in 2021 version change its name

0:54

and it affects these midline structures

0:57

and they look like this, uh,

0:59

just terrible tumor in the midline.

1:02

Patient is sometimes very minimal symptomatically altered,

1:06

but it's a tough tumor.

1:08

Surgical resection is not a possibility

1:10

because they tend to involve the deep

1:12

thalamic nuclei like this.

1:14

It's just an awful tumor.

1:17

But here's the six different patients

1:19

with the same awful diagnosis.

1:21

And they're all,

1:22

even though histologically they may look very different,

1:25

but they have histone H three K 27 M altered,

1:30

and they tend to occur in the midline.

1:33

And hence the name diffuse midline glioma

1:36

and some of these spinal cord tumor.

1:39

And most of them now are called a diffuse midline glioma.

1:43

Only when they could,

1:45

our pathologist can actually definitively identify

1:49

the histone alteration, particularly H three K 27 m.

1:55

And here's an example of a spinal cord.

1:58

We used to call this spinal cord astrocytoma

2:01

or glioblastoma, and that's, that's not wrong.

2:04

But once they get a tissue

2:06

and our pathologists look for this particular mutation,

2:10

that's how we know that this is a diffuse midline glioma.

2:14

H three K 27 M altered.

2:16

Here's a patient I saw,

2:18

but what does it mean for radiologists?

2:20

So we're not the one who's gonna diagnose H three K 27 M

2:24

molecular features, but I want you to remember

2:27

that these are really terrible tumors they sneak around.

2:31

They actually can spread all along the CSF

2:34

as if they are metastatic pineoblastoma

2:38

or mesoblast stomachs.

2:39

And keep an eye on brain.

2:42

Any lesions in the brain cannot be ignored.

2:45

So let me show you, this is one of our patient

2:48

for many years ago, uh, when we first, uh,

2:51

our pathologist started to test for the H 20, um,

2:56

H three K 27 m after radiation

2:59

Therapy. Our radiation

3:00

oncologist did a great job.

3:02

Uh, some of these enhancing tumor looks better,

3:05

the flare looks better too.

3:07

But remember this original flare imaging of the brain,

3:11

we were not sure whether this was really a real finding

3:14

or is that a tumor?

3:16

But five months later, you could see all

3:18

of those areas are now nodular and patient recurred.

3:23

And unfortunately the real, um, down, uh, the tumor

3:28

that they couldn't control was not the spinal cord

3:31

diffuse midline glioma.

3:33

It was the CSF ependymal, lepto leptomeningeal spread

3:37

of the original tumor.

3:39

And this is how diffuse midline glioma, H three K 27

3:44

m alter tumor behave on follow-up imaging.

3:48

So please make sure you get brain imaging

3:50

to make sure we don't miss this very subtle, uh, lesions

3:54

that show up on flare imaging alone.

3:57

These areas may not enhance at all.