0:01

When looking at inner ear pathology,

0:03

the neoplasms are a relatively small amount of

0:06

the pathology that affects the inner ear.

0:09

I would say less than 5%.

0:11

This is if we're excluding the internal auditory canal

0:14

where we have our vestibular schwannomas,

0:16

and that would be considered a posterior fossa

0:21

intracranial lesion as opposed to

0:23

an inner ear lesion. However,

0:24

there are some neoplasms that can occur in the inner

0:27

ear, and we'll first start with the benign ones.

0:30

Here we have a patient who has an area of

0:34

enhancement within the vestibule of the semicircular

0:39

canals and labyrinthine structure.

0:41

So the internal auditory canal is seen anteriorly.

0:45

We have the cochlea,

0:47

but we have this focal area of enhancement on this

0:50

post-gad T1-weighted and fat-suppressed scan

0:53

provided to me by Azito Horsandi.

0:55

If you look on the Fiesta T2-weighted scan,

0:58

you see that within the normal bright

1:01

signal intensity of the vestibule,

1:04

you have a soft tissue mass,

1:05

and this represents that schwannoma.

1:08

Here's another example.

1:11

On this case,

1:12

we see that there is enhancement of the basal

1:16

turn of the cochlea on the right side,

1:19

which is obliterated on the CISS image.

1:23

Here is the normal side on the left side,

1:26

where you have the complete turns of the cochlea

1:28

and absence of contrast enhancement.

1:31

And this is an example of a cochlear schwannoma.

1:35

It's a type of labyrinthine schwannoma affecting

1:38

the basal turn of the cochlea.

1:40

Now, how do I know that this is not a labyrinthitis?

1:44

How do we know that this is not enhancement

1:46

secondary to an inflammatory process?

1:48

It's difficult to tell if you don't have expansion

1:52

of the cochlear turns or, as in this case,

1:55

the vestibule itself.

1:57

So what one does is you may treat for the

2:02

labyrinthitis and then do a follow-up scan.

2:04

And if there is persistent enhancement

2:06

and persistent symptoms,

2:08

that would suggest that this represents a schwannoma

2:10

as opposed to inflammatory enhancement.