0:01

Yet another patient with retrotympanic vascular mass.

0:04

I'm not sure why all these are occurring on the right,

0:07

on the right-hand side.

0:08

But here we have our high-resolution temporal bone CT.

0:12

And as we go from the external auditory canal

0:18

and we look into the middle ear cavity,

0:21

from there, we see that there is a mass which is

0:25

bubbling up from the medial inferior posterior wall.

0:32

And it is this lesion that was seen at otoscopy.

0:37

So here we can

0:39

faintly see the tympanic membrane.

0:42

And what they saw was a retrotympanic vascular mass

0:47

along the posterior aspect of the tympanic cavity.

0:50

So this is different.

0:52

This is not located overlying the cochlear promontory

0:56

which is this bony edge here.

1:00

However,

1:02

it does get just below, here is our round window niche.

1:06

And just below it is where this lesion is coming from.

1:09

As we course further inferiorly on the CT scan,

1:14

we see that there is erosion of the bone associated

1:18

with the jugular foramen. So here's our jugular foramen,

1:21

and we don't even see that rounded nature to

1:23

it anymore because it's been expanded.

1:26

Not only that,

1:27

but it looks as if this jugular foramen mass has taken out

1:31

the posterior wall of the internal carotid artery.

1:35

So here's our cavernous carotid artery

1:36

and our posterior carotid canal,

1:39

and the wall there has been eroded by this

1:43

infiltrated mass. And here, again,

1:46

you can see portions of the mastoid

1:48

bone have been eroded as well.

1:50

So this is, indeed, a glomus jugulotympanicum.

1:54

It was centered in the jugular foramen

1:57

on the right side, however,

1:58

it grew superiorly and anteriorly to enter the middle

2:03

ear cavity and present as a retrotympanic vascular

2:07

mass, a red mass. These lesions, again,

2:10

generally cause some element of pulsatile

2:13

tinnitus, as well as hearing loss.

2:17

And they will present in the same way a glomus

2:23

tympanicum and a glomus jugulare and a glomus jugulotympanicum. The glomus jugulare, however,

2:27

has the potential for erosion of other cranial nerves.

2:34

So as we look up further superiorly here,

2:38

we can see that there is involvement at

2:40

the level of the endolymphatic sac.

2:43

We see the jugular foramen eroded,

2:46

and therefore, one can have 9th, 10th,

2:49

11th cranial neuropathies.

2:51

And sometimes it even erodes the hypoglossal canal.

2:55

This hypoglossal canal,

2:56

if we look on it and compare side to side,

3:00

right and left hypoglossal canals,

3:02

we might suggest that this one is

3:05

expanded compared to this one.

3:08

And therefore, we may have a tumor even down

3:10

affecting the 12th cranial nerve.

3:13

So let's look at the MRI scan of this case.

3:17

We'll skip to the post-gadolinium enhanced images.

3:21

These are post-gadolinium VIBE images.

3:26

And as you can see,

3:28

the thickness by slice location is 0.8 mm thick.

3:32

So, very thin sections. And even down here,

3:36

we can immediately tell that there is soft tissue which is

3:41

growing into the jugular vein here

3:46

through the skull base.

3:47

This is not a normal flow of a jugular vein.

3:50

This is soft tissue in that jugular vein.

3:53

And we can also see the soft tissue

3:54

growing into the sigmoid sinus.

3:56

So here's our jugular foramen growing

3:59

into the sigmoid sinus distally.

4:01

This portion of the sigmoid sinus looks good,

4:03

and the transverse sinus looks fine.

4:05

But this is what glomus jugulare can do.

4:08

They can grow into the venous structures, both

4:11

inferiorly into the jugular vein and

4:14

superiorly into the sigmoid sinus.

4:17

You notice that the concern we had for the hypoglossal

4:21

canal is well-founded, and that there is soft tissue

4:24

just adjacent to there that might be

4:26

affecting the 12th cranial nerve.

4:28

And here is the portion that is growing up into

4:31

the mastoid and the small portion right here,

4:34

that's growing into the middle ear cavity.

4:37

External auditory canal, middle ear cavity region here.

4:40

So let's see if we can look at the jugular

4:46

vein on the coronal images.

4:50

Here's our carotid canal, our carotid artery,

4:53

and we're not really seeing a good jugular flow void.

4:58

And on our CIS images, again, expanded jugular vein.

5:06

Compare the flow void of the jugular vein over

5:10

here versus that of the affected side,

5:13

and you see this big wall of soft tissue

5:16

extending even into the sigmoid sinus.

5:19

So confirming our suspicion of a glomus

5:23

jugulotympanicum with erosion of the jugular

5:26

foramen and likely involvement

5:29

here, you can see the hypoglossal nerve coming through

5:33

the hypoglossal canal and then getting caught up in the

5:36

soft tissues with infiltration also

5:39

of the right jugular vein.