0:01

This is another example of a patient who had

0:03

pulsatile tinnitus and was found to have

0:05

a retro-tympanic vascular mass.

0:08

As we look at the temporal bones of this CTA,

0:12

the CTA was performed to identify

0:15

why he had pulsatility.

0:17

And what one sees is a soft tissue mass which is

0:21

showing minimal contrast enhancement and extends

0:24

along the surface of the cochlear promontory

0:27

and extends even into the round window.

0:30

This mass was read on otoscopy,

0:34

and therefore the most likely diagnosis,

0:37

given the location and the clinical history,

0:40

is a glomus tympanicum. Now,

0:42

the differential diagnosis, as I mentioned,

0:45

includes glomus jugularis growing upward.

0:48

In this case, once again,

0:50

we have a good-looking jugular foramen.

0:52

Here's the carotid artery and here's the jugular

0:55

foramen on the ipsilateral side.

0:57

The other thing to look at is the posterior

0:59

wall of the internal carotid artery,

1:03

the carotid canal. If this wall is missing,

1:07

one has to be concerned about the potential

1:10

for an aberrant internal carotid artery,

1:12

which can extend into the middle ear cavity.

1:17

So always watch and make sure you're seeing that

1:20

posterior wall of the internal carotid artery

1:24

when you're making a diagnosis

1:25

of glomus tympanicum.

1:27

The other thing that can occur here is a

1:29

diverticulum off of the jugular bulb and that

1:33

can extend and look like a glomus tympanicum.

1:37

The importance of these vascular anomalies is

1:39

that if you make a mistake and the surgeon goes

1:43

in via a tympanotomy that is going through the

1:47

tympanic membrane and encounters the internal

1:50

carotid artery, inadvertently,

1:53

what you have is pulsatile.

1:55

Blood coming through the tympanic membrane at

1:57

the otoscope and no way of controlling the

2:00

internal carotid artery. Or, for that matter,

2:03

if it was a jugular aneurysm.

2:06

The venous side of things as well.

2:10

So important differential diagnosis in this case.

2:13

Retrotympanic vascular mass overlying

2:15

the cochlea, glomus tympanicum.