0:01

So what are we to do with this abnormality?

0:03

We're at the T9 level in a 42-year-old male,

0:06

and we see on this sagittal reconstruction of

0:09

the axial scan, a calcification which

0:13

appears to be within the thecal sac.

0:16

So rarely, you can get disc herniations,

0:20

which will calcify and occasionally

0:24

perforate the thecal sac.

0:25

But that would be two unusual things.

0:27

You have a calcified disc and you have one

0:29

that's perforating the thecal sac and then

0:31

presenting as if it was an intradural extramedullary lesion.

0:34

Doesn't make a lot of sense. When we look

0:37

at this lesion, it's kind of cute,

0:39

but it does look like there is a dural

0:42

tale of calcification, if you will.

0:45

So you'll note that there is this little

0:47

hyperdense area which is emanating from the

0:50

lesion and going superiorly along the dura.

0:53

This might be the clue that this is indeed

0:57

an intradural extramedullary calcified

1:00

meningioma of the thoracic spine.

1:03

Most meningiomas of the thoracic spine

1:05

occur along the posterior dura,

1:07

not the anterior dura.

1:10

The other clue that this is not a disc

1:12

herniation is that on the axial scans, we don't

1:14

really see it attaching to the disc.

1:17

We seem to have intervening disc between the

1:21

lesion and therefore it's not an extradural

1:24

disc herniation. It's really an intradural mass,

1:27

a meningioma. Let's look on MRI.

1:31

So this is a different patient with a more

1:33

characteristic appearance of a meningioma.

1:37

T1-weighted scan.

1:39

Let's just review the anatomy real quickly.

1:41

We have the vertebral body, we have the disc.

1:44

We have the CSF space anterior to the spinal

1:48

cord. We have the spinal cord.

1:50

We have the CSF space posterior to the

1:53

spinal cord. We have epidural fat.

1:55

An epidural fat may be very thickened in

1:59

patients who have epidural lipomatosis.

2:02

Then we come into the spinous processes back

2:06

here. And between the spinous processes,

2:08

you have some fat as well.

2:10

Let's look at the lesion.

2:11

The lesion is in the thecal sac.

2:14

There is a meniscus sign which is better seen

2:16

on the T2-weighted scan where the

2:18

CSF space is, if anything,

2:20

widened at the level of the tumor

2:23

as opposed to being narrowed.

2:25

And it's clearly along the posterior dura.

2:28

Not only that,

2:29

but we have some accentuation of

2:32

the dark signal of the dura,

2:34

suggesting that it is thickened

2:36

and possibly even calcified.

2:38

This would identify the lesion as most

2:40

likely representing a meningioma.

2:43

The spinal cord is displaced anteriorly.

2:46

It's important for us to make a comment about

2:49

the spinal cord signal intensity.

2:51

If we think that the spinal cord

2:52

signal intensity is bright,

2:54

it may correlate with clinical symptoms

2:57

of a myelopathy. It may encourage

3:00

the neurosurgeons to remove this

3:02

tumor more readily and more quickly,

3:05

as opposed to waiting for the lesion

3:08

to demonstrate interval growth.

3:11

So even when you have an intradural

3:14

extramedullary lesion,

3:15

you do want to make a comment as to whether

3:17

or not it is leading to cord edema,

3:21

which might precipitate a more aggressive

3:24

stance by the neurosurgeons

3:26

to remove the lesion.