0:01

I've referred to the ependymomas of the

0:04

intradural extramedullary space.

0:07

These are typically called the filum terminale

0:10

ependymomas or myxopapillary ependymomas.

0:13

And they are not in the spinal cord,

0:16

but in the little fibrous tissue at the end

0:18

of the spinal canal, the filum terminale.

0:22

These are grade 1, low-grade tumors,

0:26

generally considered benign,

0:27

that can be removed surgically.

0:30

There's a slight male predilection.

0:32

They're very slow growing.

0:34

These may have calcification or hemorrhage

0:36

or cystic change within them.

0:39

This lesion looks almost exactly like our cystic

0:43

schwannoma that we referred to previously.

0:46

However, this was a myxopapillary ependymoma.

0:50

The features of it that would be suggestive of that

0:54

are the cystic nature of the lesion, as well as

0:57

its occurrence here at the filum terminale.

1:00

So the filum terminale lesions generally are more

1:04

centrally located than nerve root lesions.

1:07

Nerve roots are going to be in the

1:08

periphery of the thecal sac.

1:10

The filum terminale would be in the center of the thecal sac.

1:14

It is not uncommon for them to have mixed signal

1:17

intensity because of the possibility of cysts or

1:21

hemorrhage, or occasionally even calcification.

1:24

The location in the center of the thecal sac, as opposed to

1:27

the periphery, would also be a feature that would

1:31

suggest a filum terminale ependymoma.

1:34

These lesions are very slow growing.

1:37

They may remodel bone. And in point of fact, on this sagittal scan,

1:41

you might wonder about whether there's a little bit of

1:45

posterior scalloping of L4 associated with

1:49

the ependymoma. Most of these ependymomas,

1:51

when they're discovered,

1:52

are large lesions because they are relatively

1:56

asymptomatic and they're slow growing tumors.

1:59

Sometimes you will see them erode through the bone and

2:03

infiltrate the sacrum quite widely

2:06

and, actually, extend extradurally.

2:09

So this is yet another of the intradural extramedullary

2:12

tumors that can occasionally become extradural

2:16

outside the thecal sac. And here's an example.

2:20

This is a myxopapillary ependymoma, and frankly,

2:26

it looks very aggressive, right?

2:29

So let's look at this T1-weighted scan in the center here.

2:33

Notice that there is scalloping of the bone.

2:36

So, it's maybe some features that suggest slow growing.

2:39

But look at the sacrum.

2:41

This is the S1 bone and this is the S2 bone.

2:44

So this is an example of an intradural extramedullary

2:48

benign tumor that is infiltrating the sacrum

2:54

in a very aggressive fashion.

2:55

You can see the...

2:57

actually, on the T2-weighted scan, this bright signal intensity

3:00

of sacral bone invasion by a benign

3:05

myxopapillary ependymoma.

3:07

And you see also that it does show contrast enhancement.

3:11

So an intradural extramedullary lesion that is growing

3:14

extradurally and is yet a benign tumor.

3:19

On the axial scan,

3:20

you can see that there also was growth posteriorly

3:23

through the posterior elements,

3:24

which you're seeing here by this mass.

3:27

Now, this mass presented at this size.

3:31

So, it just goes to show how these lesions are relatively

3:35

asymptomatic slow growing and present

3:38

as a very large lesion.

3:39

This lesion is going to be still operated on surgically

3:43

because it can still be resected and

3:47

have a relatively good outcome.