0:01

This is an adolescent with neurofibromatosis type 2.

0:04

You see the bilateral vestibular schwannomas with

0:07

filling the internal auditory canals,

0:09

extension through an enlarged porus acusticus,

0:11

effacement of the cerebellopontine angle on the left,

0:14

partial effacement of the cerebellopontine angle on the right.

0:19

If we go a little bit lower, we can actually see a right

0:24

sided schwannoma along the cranial nerve, either 9 or 10,

0:31

The cisternal segment of either cranial nerve 9 or 10,

0:33

going from the lateral aspect of the

0:36

medulla oblongata towards the jugular foramen.

0:39

We see here,

0:42

this tentorial meningioma.

0:46

We see a meningioma

0:50

adjacent to the superior sagittal sinus near the vertex.

0:55

And anteriorly, we see a parafalcine meningioma.

1:00

So, this patient has multiple intracranial manifestations

1:04

of neurofibromatosis type 2, beyond just the more

1:09

characteristic bilateral vestibular schwannomas.

1:12

Looking at spine imaging,

1:15

we see likely intradural lesions

1:19

of spinal cord ependymomas.

1:20

But we're also seeing intradural extramedullary lesions,

1:26

likely schwannomas and possibly

1:29

this one representing a meningioma.

1:33

We see more inferiorly as we go to the lumbar

1:38

portion, we see innumerable enhancing lesions

1:43

along the nerve roots of the cauda equina.

1:45

These are multicentric schwannomas.

1:49

Again, multicentric.

1:52

Because of the germline mutation in chromosome 22,

1:57

this patient is predisposed to developing lesions.

2:01

So, with the two-hit hypothesis going with one of

2:07

the copies of the gene being abnormal, all you need

2:13

is a single mutation in the normally functioning

2:17

version of the gene to result in a tumor.

2:19

In individuals without neurofibromatosis type 2,

2:23

even a single mutation in one of the two copies of this

2:26

gene does not result in a tumor because the other version

2:32

of the gene still functions normally.

2:35

In a patient with

2:36

neurofibromatosis type two, one of the copies of the gene

2:40

is not working properly to begin with, then a mutation

2:44

in the other copy will end up resulting in a tumor.

2:48

So, that happens in each one of these separate spots.

2:51

So these are not metastatic lesions.

2:52

This is multicentric disease.

2:55

That's an important concept to

2:57

recognize for inherited tumors.

3:00

The difference between metastatic spread,

3:03

versus multicentric disease.

3:06

So, this patient has neurofibromatosis type 2

3:09

with bilateral vestibular schwannomas, multiple

3:11

intracranial meningiomas, multiple spinal schwannomas

3:15

and also likely at least one spinal ependymoma.