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I'd like to review this case of a patient who had a left

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sided cholesteatoma that had been treated surgically.

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It's a little bit of a complicated case,

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but I think it's a good one to go over with you.

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So what you're seeing is the affected left side thin section

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images and the right side, which, although not normal,

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is not the side that we're going to be focusing on.

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If we look at the patient's temporal bone,

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I like to start with going from external ear to middle ear.

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And then we'll also discuss the inner ear structure.

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So the external auditory canal cartilage

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portion looks good.

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When we come to the bony portion

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of the external auditory canal,

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you notice that it is misshapen and that there appears

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to be a divot out of it posteriorly.

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When we compare the right side, for example,

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you see that nicely the posterior wall

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of the bony external auditory canal.

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So the loss of that posterior wall of the external canal

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should identify for you that this patient

1:05

has a canal wall down mastoidectomy.

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We're talking the posterior wall of the external auditory canal

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has been taken down, a canal wall down mastoidectomy.

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So this does not look normal.

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This patient has had surgery.

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If you look at the rest of the bony external canal,

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it doesn't look bad until we get to the tympanic membrane.

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Now, this tympanic membrane is a little bit more dense than

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one would normally see with the tympanic membrane.

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And it may have an element of something called

1:35

tympanosclerosis that is a little bit of fine calcification

1:39

associated with this tympanic membrane.

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Deep to the tympanic membrane,

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in the middle ear cavity, we are seeing a mass,

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and this mass is the patient's cholesteatoma.

1:49

So as I'm looking at the patient,

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I've looked at the external canal.

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Now into the middle ear analysis, and of course,

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we want to look for the ossicles.

1:58

In this case, we're seeing

2:00

something that's very dense,

2:02

but does not look like our ice cream cone and

2:05

parallel lines that we would see on the normal side.

2:08

Here's our ice cream cone and then the parallel

2:13

lines of the neck of the malleus and the

2:15

long process of the incus.

2:17

Instead,

2:18

what we have is something that is clearly an ossicular

2:22

replacement prosthesis. Now, the question is,

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is this a total ossicular replacement prosthesis or TORP,

2:30

or is it a partial ossicular replacement prosthesis,

2:34

what we call PORP? And the key here is,

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is there an intact stapes?

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And although it's surrounded by soft tissue,

2:43

what we can see is that the stapes is a natural stapes.

2:47

Here's the core of the stapes.

2:49

Here, maybe you can be a little bit more convinced of it.

2:52

And this is a partial ossicular replacement prosthesis,

2:57

which articulates with the capitulum of the stapes.

3:00

So this is an ossiculoplasty, a PORP.

3:06

So looking at the additional findings in the middle ear

3:10

cavity, you see this big mass that has eroded bone.

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What bone has been eroded?

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So if we look at where this soft tissue is,

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we see this very unusual erosion here of the bone,

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which is communicating with the cochlear aqueduct.

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This down here is the cochlear aqueduct.

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Just above it is the internal auditory canal.

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So below the internal auditory canal,

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the thing that looks a little bit like a small internal

3:41

auditory canal is the cochlear aqueduct.

3:44

And you see that this cholesteatoma

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has taken an unusual path to erode the bone

3:50

around the cochlear aqueduct.

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And it comes even here to a portion of the internal

3:59

auditory canal, posterior wall. Normally,

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the areas that we look for cholesteatoma,

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dehiscence, and erosion are along the facial nerve.

4:08

So let's look at that.

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So here's the facial nerve canal.

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Here's the tympanic portion of the facial nerve,

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which looks pretty good coming through here.

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However,

4:18

this is an unusual case in that the descending portion of the

4:23

facial nerve seen here ultimately shows an area of dehiscence

4:28

right here by this inferiorly growing cholesteatoma.

4:34

With this inferior and posterior growing cholesteatoma,

4:38

we're more likely to suggest that this

4:40

is a pars tensa cholesteatoma,

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as opposed to the more traditional pars flaccida

4:47

cholesteatoma, which tends to grow up and erode

4:50

the tegmen tympani, the roof of the temporal bone.

4:53

This doesn't have anything up here in the epitympanic space,

4:56

the high space. It's actually eroding down

5:00

and picking off the descending intramastoid portion

5:04

of the facial nerve with an area of dehiscence.

5:08

So, a somewhat complicated case, but one, I think,

5:12

that nonetheless shows you the potential for cholesteatomas

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to erode bone in unusual locations.

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And also the postoperative changes of a canal wall

5:23

down mastoidectomy,

5:25

an ossiculoplasty with a PORP communicating with the native

5:30

stapes in this patient with recurrent cholesteatoma.