0:00

Dr. Laser,

0:01

this is a 59-year-old woman with blurred vision.

0:04

We're not really in the visual area at all.

0:07

We're up high in the frontal region,

0:09

involving the middle and,

0:12

to a lesser extent,

0:13

the inferior frontal gyrus,

0:14

and we have a mass here that looks extra axial,

0:18

doesn't it?

0:19

Correct.

0:19

It's got a very,

0:20

very sharp interface with the underlying brain parenchyma,

0:24

and it's interesting that it does not

0:27

generate much, if any, vasogenic edema.

0:30

There was also a curious-looking area of tissue

0:33

thickening around it that looks separate from it

0:36

that that may be some additional

0:38

tissue in the dura.

0:40

It may be a small hemorrhagic or proton

0:42

suffusion or it may simply be tumor.

0:45

We don't have a contrast enhanced study.

0:46

If I had to bet, I'd bet on tumor.

0:49

And the reason I would is because it's still gray

0:51

over here, it's not fluid like on the T two.

0:54

So I like it a lot for just a strange

0:56

continuation of the same lesion.

0:59

And then when you look at the calvarium,

1:01

the diploic space signal is just completely

1:03

wiped away on the T one.

1:05

I like to have a true T one in almost every

1:08

skeletal study that I ever do. Now,

1:09

granted this is a neural study,

1:11

but there's a skull here involved

1:13

and that is sket at all.

1:15

So I like a true t one as opposed

1:17

to opposed to a proton density,

1:18

and look at how thick the calvarium is.

1:21

And then on the outside of the calvarium,

1:23

we have another layer.

1:25

So this is like an incredible club sandwich.

1:27

You know, you've got the Galia,

1:28

you've got the outer table here and on top of

1:32

the outer table, subgaleal is this mass.

1:34

You've got the diploic space which is abnormal.

1:37

You've got the inner table which is thick and

1:39

you've got a band-like area of tumor and then

1:42

you've got a lentiform area of mass and or

1:46

tumor and then you've got the brain.

1:48

So that's how I would dissect the signals.

1:50

In this case, it's a low field study.

1:52

The patient moved a little bit but still

1:54

the teaching is there axial T one,

1:57

axial T two coronal flare.

1:59

So the take-home message here is what

2:00

do you do with this lesion?

2:02

What's the differential diagnosis?

2:04

And let's throw out some differential diagnoses.

2:07

I mean, I would, you know, I would consider,

2:09

you know,

2:10

something like a primary bone tumor of the skull,

2:12

including a sarcoma.

2:15

I'll start out with some weird things like sarcoid

2:17

and even tuberculosis. And you know what I like,

2:20

especially when I have very gray signal.

2:23

Not a lot of high signal because there's

2:25

not a lot of cytoplasm in lymphoma,

2:27

seeing lymphoma do this and kind of sweep

2:29

its way right across the calvarium.

2:32

And even though it wipes out the calvarium,

2:35

it's surprising how little surrounding

2:37

reaction it generates.

2:38

What are some other things

2:39

you would consider here?

2:40

What would you think about a Chloroma in this

2:42

case? I'd like Chloroma a lot. The only,

2:44

the only thing I would say is,

2:46

uh I wrote the first Chloroma paper,

2:48

an MRI back in 1990 in the Jurassic period is that

2:51

they're kind of, they're kind of nodular,

2:53

they're kind of round. They tend not to be,

2:56

not to be flat but,

2:58

but they are bulky and they come from patients

3:01

that have acute myelogenous leukemia.

3:03

So they're nests of myeloid cells

3:05

and that could occur at any age,

3:07

any age that you can get AML you can get

3:09

a chloroma. So that's a great thought.

3:12

Anything else? So look all things being common.

3:15

One thing that I would consider

3:16

obviously extra-axial lesions,

3:18

men would be included in there and then down the

3:21

spectrum of aggression of meningioma

3:23

all the way to Parma. Yeah.

3:25

And hemangiopericytoma used to be

3:28

in the family of meningioma.

3:29

It was considered kind of the ultimate aggressive

3:31

meningioma in the type three category. Now,

3:34

it's been reclassified as a fibroid

3:37

tumor all by itself.

3:38

But let's talk about meningioma types

3:40

while we're at it. You know,

3:42

you've got the grade one meningioma,

3:44

which is meningioma.

3:47

the fibrous or fibroplastic type.

3:49

More common in the skull base and sphenoid

3:52

transitional mixed simo angios microcystic

3:57

secretory lymphocyte-rich and metaplasia and some

4:00

of these may generate exuberant vasogenic

4:03

edema as we've discussed before,

4:05

due to the production of the vascular endothelial

4:09

growth factor. Grade two. Fortunately,

4:12

there aren't as many there to memorize.

4:14

There's only, there's only three.

4:15

And what are those typically clear cell

4:17

cordo and then atypical by histology.

4:21

And then you know,

4:22

those will behave a little more aggressively.

4:24

It's not possible by MRI to select

4:27

out the individual histology.

4:28

But it is possible to say if it's low grade or,

4:31

or high grade,

4:32

grade three and the grade three ones,

4:34

what are theologies there?

4:36

Papillary and also anaplastic,

4:38

right would be your grade three.

4:39

And then they used to say hemangiopericytoma,

4:41

they would grade that as either a two,

4:43

a low grade hemangiopericytoma or a three.

4:46

And as we said,

4:47

that's been taken out of the Meningioma World

4:51

Health Organization grading system,

4:52

which we just gave you and it's been reclassified

4:55

as it should be in the musculoskeletal

4:58

tumor group, the fibrohistoid group.

5:01

So this is an aggressive lesion.

5:03

We've given you an extensive

5:05

differential diagnosis.

5:05

I left one thing out actually one very important

5:08

thing and that is melanotic lesions of the dura.

5:12

They're kind of gray. They may be pigmented,

5:15

they may not when they are pigmented,

5:17

they're pretty dark on T two.

5:19

They're intermediate to bright on T one.

5:22

You can not only have melanoma of the dura,

5:24

you can have melanosis or hypermelanosis of ito.

5:27

And that's one that people often overlook and

5:30

the melanoma lesions are very aggressive.

5:33

They go through bone.

5:34

So that's got to be in your

5:36

differential diagnosis.

5:37

Whenever you have one of these lesions that's

5:39

going from one compartment to the other and

5:41

destroying the calvarium or skull. Let's move on.

5:45

Shall we, Lazar? Out, out, out?