0:01

We're going to segue from our infectious etiologies of

0:06

extradural disease into the neoplastic category.

0:10

You've seen the discussion of

0:12

nerve sheath tumors before,

0:14

both when we were dealing with intradural intramedullary

0:17

lesions, as well as intradural extramedullary lesions.

0:20

I just want to refresh your memory that in 15% of cases,

0:25

the nerve sheath tumor in the spine may be completely

0:28

extradural and in another 15%, it may be the so called

0:33

dumbbell lesion, which has both an intradural compartment

0:37

as well as an extradural component.

0:40

Here, for example,

0:41

is a patient who has a cystic schwannoma in the lumbar spine.

0:46

It is causing enlargement of the neuroforamen on the

0:50

right side and is displacing the

0:52

thecal sac to the left side.

0:55

Do not be confused by the bright signal

0:58

on the T2-weighted scan.

0:59

Remember that we've seen lesions that are bright on

1:03

T2, which still shows avid contrast enhancement.

1:07

So this is not a cyst.

1:09

This is in fact a tumor.

1:12

And in this case, a schwannoma in the neuroforamen.

1:15

Here it is on the pre-contrast T1-weigghted scan.

1:19

Contrast that with this case that was also shown when

1:23

discussing intradural extramedullary lesions.

1:27

Here we have the schwannoma, which is extending from the

1:32

intradural extramedullary location into an extradural

1:37

location in the left neuroforamen.

1:40

So again,

1:41

if we look at this purely on the T2-weighted scan,

1:45

it is very bright. We might say, well,

1:47

could that just be a big cyst?

1:49

As you note on the post-gadolinium enhance scan, however,

1:53

this lesion is solidly enhancing. And right

1:56

about here is our border with the dura.

1:58

So we have a component that is intradural extramedullary,

2:02

as well as the component that is extradural

2:06

and extending out into the far neuroforamen.

2:09

So an intradural extradural dumbbell schwannoma.

2:12

I also showed this slide in the previous talk on

2:16

intradural extramedullary lesions to show that the

2:20

patients who have neurofibromatosis type II might

2:24

have lesions intradural, as well as extradural.

2:26

In this case,

2:28

big lesions in an extradural location, actually,

2:31

intramuscular even, as well as some that

2:34

are intradural but extramedullary.

2:37

And this is part of the neurofibromatosis type II

2:40

syndrome, also known as MISME for

2:43

Multiple Inherited Schwannomas,

2:45

Meningiomas, and Ependymomas.

2:47

Neurofibromas are more characteristically found in patients who

2:52

have neurofibromatosis type I.

2:54

And these lesions as well may be extradural

2:57

or intradural. Sometimes, they may be associated also

3:01

with intramedullary lesions

3:03

like neurofibromatosis type II,

3:05

the latter causing ependymomas, whereas neurofibromatosis

3:09

type I, associated with astrocytomas of the spinal

3:12

cord. The dural ectasias and arachnoid

3:15

cysts and scalloping are also a manifestation

3:18

of neurofibromatosis type I. In children,

3:22

we also consider the neuroblastoma, ganglioglioma lesions that

3:28

occur in a paraspinal location.

3:30

In this case,

3:31

we see them in the anterior paraspinal location.

3:35

However, they may be laterally located or they may extend

3:39

into the neuroforamena. This big lesion,

3:42

although predominantly anterior to the spinal canal, we

3:45

see it goes into the neuroforamena, and in that way, can

3:50

actually cause compression of the thecal sac.

3:54

This, by the way, is the kidney.

3:55

So let's not be distracted by that.

3:57

So neuroblastomas and ganglioneuromas and gangliomas are

4:03

lesions that will vary in the histology depending upon

4:06

the age, with the neuroblastomas being those

4:09

that occur in the youngest age group.

4:11

On the axial scan, we see this big lesion

4:13

here representing the ganglioneuroma.