0:00

Okay, so this was a patient that had right ear and jaw pain.

0:05

So the abnormality here

0:09

is this diffuse thickening and enhancement involving the right external auditory

0:14

canal. And uh, when we give contrast,

0:19

uh, uh,

0:20

when we give contrast the lesion this abnormality diffusely enhances.

0:24

So we have all of this enhancement right here.

0:26

Now what I didn't tell you on this one is that the patient had a fever and I,

0:30

I didn't, and I didn't tell you,

0:31

I don't think I put in the history of the patient was diabetic 'cause I didn't

0:34

want to give it to give it away. So what really, what I'm more interested in is,

0:37

is your differential diagnosis.

0:40

So the main differential when you see something like this really is gonna be

0:43

without the history, is gonna be a diffuse otitis externa,

0:48

malignant otitis externa or potentially squamous cell carcinoma.

0:53

So anyway,

0:53

if I told you the patient was diabetic or some type of immunocompromised or

0:57

immunodepression, you can suggest a diagnosis of malignant otitis externa.

1:02

Also, we can call it skull-based osteomyelitis. Now,

1:06

one point that I want to make on this, um, is that when you look at the,

1:11

and see if I can do this correctly here,

1:14

I'm gonna go from the left side to the right side.

1:16

And this is a little bit subtle, but everyone see this right here.

1:20

You see the temporomandibular joint?

1:21

You see the condyle right here and you see the fat plane right here.

1:26

Notice how on the right hand side,

1:30

see how this flat plane's obliterated here. So I haven't written this up there.

1:35

I kind of call this the stripe sign because um,

1:39

in general when we look at areas here adjacent to the skull base,

1:43

you normally should see some nice stripes here.

1:45

I always call 'em my tiger stripes. So you can see the cortex right here,

1:48

the bone, and you can see the fat and then you can see the condyle,

1:51

the mandible.

1:53

And on the opposite side you can see how that's kind of all grayed out.

1:56

So that really is a very,

1:58

very early finding of extension of the skull base osteomyelitis

2:04

into, uh, a malignant otitis externa into the deep skull base.

2:09

Now Howard, it gets there and hopefully this was gonna show up.

2:13

So just gimme a second, is I'm gonna show you, um,

2:18

a couple of cases, uh, from one of my talks.

2:22

So when we look at, uh, malignant otitis externa,

2:26

the patients that are at risk or diabetic patients with poorly controlled

2:30

glucose, um,

2:31

you can have patients that are immunosuppressed and I actually would prefer

2:36

to use the term immuno depressed because, you know, if you're in a, in,

2:41

in a hospital setting, you typically see this with uncontrolled diabetics.

2:45

But one thing that I have seen, you know,

2:47

over the last few years is that the patients that actually,

2:50

that I've seen get this more commonly in the community are actually immuno

2:55

depressed. So what I mean, immuno depressed, they still may have diabetes,

2:59

But they still could be controlled. They may be,

3:01

they may have some type of rheumatologic abnormality that depresses their immune

3:05

system. So just realize you can see this, um,

3:08

in patients that are otherwise relatively healthy.

3:11

And you can also see this in patients that have chronic otitis externa,

3:15

the organisms that are most at risk are pseudomonas and, uh,

3:19

in patients with invasive fungal diseases,

3:21

predominantly mucor mycosis or actin mycosis.

3:25

And the symptoms are otalgia fever and purulent errea.

3:29

So these arrows here point at a patient that has really bad malignant otitis

3:34

externa.

3:34

This is the case that I just showed and this is what it looks like on Mr.

3:38

So you can see diffuse enhancement here of the external auditory canal.

3:42

Now this is an example also malignant otitis externa.

3:46

Here we can see this diffuse enhancement. We can also see some bone erosion.

3:50

Now if you see this bone erosion,

3:52

this erosion could be due to aggressive skull-based infection such as

3:57

malignant otitis externa.

3:59

But this by itself could also be seen in squamous cell carcinomas and it can

4:04

also be seen in patients that have external auditory canal cluster stomas.

4:09

So just based on this appearance, you're just not gonna be able to to tell.

4:13

So that's why you do need a little bit more history.

4:17

So how do these infections extend from the external auditory canal

4:22

inferiorly into the spaces around the nasal pharynx or just below the skull

4:26

base? Well, you can have these little fissures right here,

4:30

which are these fissures in the membranous external auditor canal,

4:33

and they're referred to as the fissures of Santorini.

4:36

So what you could have is that these,

4:38

this infection extends inferiorly through the fissures of Santorini and then

4:42

ends up into the, uh, the, uh, area below the skull base.

4:47

And there's another little fissure that's located more medially. So this is, uh,

4:51

the frame of huske named after Emile Kin, who is a German anatomist.

4:56

And here we can see this little for,

4:57

and it's also known as the freeman to panicum.

5:00

So if you have infection extending through frame of, of husk or tum,

5:05

then this ends up involving the temporomandibular joint and these green arrows

5:08

here point at the diffuse flagon involving the temporal mani joint.

5:14

So that's a summary of this case, which is um, malignant otitis externa.