0:01

So now we're going to take a look at another

0:03

example of a vestibular schwannoma.

0:06

And again, this demonstrates the classic spread pattern.

0:08

And on the contrast-enhanced T1-weighted image,

0:11

we can see that a component of this is extending

0:14

deeply through the porus acusticus, to the

0:16

fundus of the internal auditory canal.

0:18

And then we still have this component here that's

0:21

extending into the right cerebellopontine angle.

0:23

Again, notice how there's no evidence of a dural tail.

0:26

But a couple of key points of this particular case,

0:29

is a whole concept of the satisfaction of search.

0:32

So you have a patient that presents

0:34

with right-sided hearing loss,

0:35

or even sometimes you'll have patients that

0:37

present with bilateral hearing loss.

0:39

Specifically, bilateral sensorineural hearing loss.

0:42

And oftentimes it's just ascribed to

0:45

as one gets older, just old age.

0:47

You may have infarcts and so on and so forth.

0:49

And you just lose your hearing as you get older.

0:52

But always remember the satisfaction of search.

0:54

So here we have a schwannoma involving

0:56

the right ear. But on the other hand,

0:58

when we look over to the opposite side,

1:00

now we see another enhancing lesion involving

1:04

the fundus of the internal auditory canal.

1:06

So when we look at the normal anatomy,

1:09

this is the posterior aspect of the porus acusticus.

1:12

There's the anterior aspect.

1:14

So unlike many of the other schwannomas that we've

1:16

seen that extend laterally into the cerebellopontine angle,

1:20

this lesion is really localized to the distal

1:24

half of the internal auditory canal.

1:26

So now we have a patient with bilateral vestibular

1:31

schwannomas. Now, this could just be idiosyncratic,

1:34

if you will,

1:35

where the patient has bilateral vestibular

1:37

schwannomas. But when you see something like this,

1:40

you have to think of syndromic causes

1:43

of vestibular schwannomas.

1:44

And one of those syndromic causes is neurofibromatosis.

1:48

So when we see bilateral vestibular schwannomas,

1:52

remember to look at other parts of the brain.

1:55

So in this particular case,

1:57

when we look at the posterior fossa

1:59

here on this lower left image,

2:01

we can see this enhancing lesion.

2:03

And what this very nicely demonstrates is this

2:06

obtuse angle with the enhancement and the dura.

2:10

And this is the classic dural tail.

2:12

So this is the meningioma.

2:15

When we look at the coronal image,

2:16

we can see another enhancing lesion

2:19

which is located in the left lateral ventricle.

2:22

This is an intraventricular meningioma.

2:25

And again, once you see one, you see two.

2:27

You may see three. And lo and behold,

2:30

here's another lesion right here involving

2:32

the convexity of the right frontal lobe.

2:36

And again, we see this very obtuse angle with the adjacent

2:40

dura, and that's a dural tail.

2:42

And this is another example of a meningioma.

2:44

So in this case, we have bilateral probable schwannomas.

2:48

Could they be neurofibromas? Absolutely.

2:51

There's no way really to tell unless

2:53

they're surgically resected.

2:55

But no one's going to resect these, obviously.

2:56

So we assume that these are bilateral schwannomas.

2:59

In this case,

3:00

there's a meningioma involving the posterior fossa,

3:03

an intraventricular meningioma, and a high

3:06

convexity meningioma, consistent with the diagnosis

3:09

of neurofibromatosis type 2.