0:01

We're going to finish our discussion of benign

0:03

neoplasms of the middle ear with this final case.

0:07

This was a patient who also had

0:09

conductive hearing loss.

0:11

And when the otoscopists looked through the

0:14

external ear at the tympanic membrane,

0:17

all they saw was opacification behind the tympanic

0:20

membrane in what appeared to be fleshy

0:23

tissue as well as fluid.

0:25

So the MRI scan was performed to assess the mass

0:29

that was suspected in the middle ear cavity.

0:33

This is a T2-weighted scan,

0:35

and what we see is what looks like fluid signal

0:37

intensity in the external auditory canal.

0:40

And then it converts to an intermediate signal

0:43

intensity lesion with possible expansion.

0:46

On the T2-weighted scan,

0:48

we see that the mastoid air cells are opacified.

0:51

And this almost looks like it's extending along the

0:55

tympanic portion of the facial nerve to the

0:58

geniculate ganglion. So a little bit confusing.

1:01

The internal auditory canal.

1:03

Is there some soft tissue in there as well?

1:06

So we rely on the post gadolinium-enhanced

1:09

scan to further characterize this lesion.

1:12

Here we have the post-gadolinium axial scan,

1:15

and indeed,

1:15

we see that there is enhancement of

1:18

the right internal auditory canal.

1:22

So there is soft tissue that's enhancing

1:24

in the internal auditory canal.

1:26

And this soft tissue that was behind the tympanic

1:29

membrane also shows contrast enhancement.

1:32

So maybe it was not fluid.

1:34

All this tissue seems to be enhancing.

1:36

And it does look like instead of

1:38

going on the facial nerve,

1:39

this is going on the eustachian

1:41

tube to the nasopharynx.

1:44

So our differential diagnosis would include a

1:46

nasopharyngeal carcinoma growing backwards along

1:49

the perineural spread to the facial nerve,

1:51

and then filling the middle ear cavity,

1:54

and then extending from there and the Geniculate

1:58

ganglion into the intracanalicular portion of

2:01

the facial nerve. So that's one possibility.

2:05

However, as we go further superiorly,

2:08

we have this unusual contrast enhancement.

2:11

And this contrast enhancement is associated

2:14

with bony thickening.

2:16

This is extraaxial tissue which is along

2:20

the middle cranial fossa floor,

2:21

as well as the Tegmen tympani with associated

2:26

hyperostosis. On the coronal imaging,

2:30

it gets even more fascinating because we have this

2:34

dural-based enhancement associated with

2:37

blistering of the Tegmen tympani bone.

2:40

You compare that to the contralateral side,

2:42

some of which is enhancing,

2:44

and then we see a tongue of tissue which is

2:48

extending inferiorly into the middle

2:50

ear cavity and then growing,

2:53

probably bulging the tympanic membrane outward.

2:57

All of this tissue shows contrast enhancement

3:00

at the same time that we also see the enhancement

3:02

in the internal auditory canal.

3:04

So if I was just describing this to

3:07

someone over the phone and said,

3:09

I have a lesion which looks like it affects the

3:12

floor of the middle cranial fossa with associated

3:14

bony blistering and dural enhancement with a dural

3:18

tail that extends into the internal auditory canal.

3:22

Well,

3:22

most people would conclude that this is meningioma.

3:26

And this is indeed an unusual meningioma with spread

3:30

into the temporal bone and middle ear cavity

3:34

from the middle cranial fossa floor.

3:37

So this ends our discussion with an unusual

3:42

benign neoplasm of the middle ear cavity,

3:45

that of an intracranial meningioma

3:48

extending inferiorly.