0:00

I'd like to make sure that everyone is comfortable with the

0:03

pathognomonic feature of an endolymphatic sac tumor,

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which may grow into the middle ear cavity or may stay within

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the mastoid and petrous portions of the temporal bone.

0:15

Here on this T1-weighted scan,

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what are we looking for?

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We're looking for a lesion which goes along parallel to the

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endolymphatic sac and has high signal intensity on

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in pre-gad T1-weighted scans.

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So as we look,

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we come upon the lesion, has bright signal intensity in

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its periphery as well. Speckled areas centrally.

0:35

It's oriented along the expected orientation of the

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endolymphatic sacro vestibular aqueduct. And as you can see,

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this one is encroaching upon the internal auditory canal.

0:48

It may end up growing into the middle ear cavity.

0:52

This one is very close.

0:53

Here's our external auditory canal coming into the middle

0:55

ear cavity. Maybe it would have been seen at otoscopy.

1:00

This lesion should show contrast enhancement.

1:03

So here on our post-contrast scan,

1:06

we see that there is a lesion which

1:08

is showing contrast enhancement.

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Compare the pre-gad to the post-gad and there's a tiny little

1:17

portion which appears to be growing

1:18

and eroding into the mastoid bone.

1:21

Probably a small portion that might have been evident at

1:24

otoscopy. Here the growth into the middle ear cavity.

1:29

So this is an example of an endolymphatic sac tumor.

1:33

And for those of you who listen to me carefully,

1:36

you should know what should I be looking at on that post-gad

1:40

scan? The cerebellum. Well, let's look at the cerebellum.

1:44

Here you go.

1:45

Solid enhancing lesion in the left peripheral cerebellum.

1:52

Another enhancing lesion in the anterior right cerebellum.

1:58

Are there any more? The next place to look is the orbits.

2:01

Because remember that you can have orbital hemangioblastomas

2:06

or angiomas associated with von Hippel-Lindau disease.

2:09

I'd be a little bit concerned about the amount of

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thickening and enhancement in the right globe.

2:15

It's a little bit irregular, a little bit more enhancement.

2:18

This is indeed a patient who has von Hippel-Lindau disease

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with multiple cerebellar hemangioblastomas

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as well as an endolymphatic sac tumor.