0:01

Dr. Shupack,

0:02

let's tackle this 52-year-old

0:03

man with a pituitary mass.

0:07

I've got before you a sagittal T1 non-

0:10

contrast MRI and a contrast MRI.

0:14

And this is really a bear of a case.

0:17

So what do you think's going on here?

0:20

Well,

0:20

there's a couple interesting things about

0:22

it because we just went through anatomy.

0:25

Right. And so we were talking about the pars distalis,

0:29

the adenohypophysis, and the stalk.

0:32

And these are really well outlined,

0:34

but not in the usual way because it's pushed

0:37

forward and draped over something.

0:40

Okay.

0:41

And so what is this something that is going to be sort of

0:44

our question that is pushing and creating this mass

0:49

effect and this very peculiar looking thing.

0:52

And it almost looks like remember going to Grandma's?

0:56

The piano stool with the eagle claw and

0:59

the crystal ball? I had one of those.

1:02

Yeah, I have one of those.

1:03

And a grandma, too. Yeah, that's right.

1:05

Chippendale Furniture is what that was called.

1:08

And that's kind of what it looks like.

1:09

Or a claw of some sort.

1:11

Yeah, maybe a bear's claw,

1:12

because it is a bear of a case.

1:14

So what you're saying is this mass is extrinsic to

1:18

the pars distalis, not arising in the pars distalis,

1:21

and the distalis is over here with the stalk draped

1:25

in front of it and the mass is behind it, right?

1:27

That's correct. And also, this is the T2 image.

1:31

And you see there's something sort of right here.

1:34

So there's a really bright portion that's probably

1:37

a cystic portion, but also within it,

1:40

there's an area that looks to me like it

1:43

could be solid, but does not enhance.

1:46

So we have something that is cystic mural nodule,

1:50

which is non-enhancing with mass effect both

1:52

on the stalk and on the pars distalis.

1:56

So I think that leads us to a discussion

1:58

of cystic intrasellar masses. Now,

2:01

the most common intrasellar cystic mass is

2:05

partially empty or completely empty sella.

2:07

And that can produce enlargement of the sella,

2:09

but that would really communicate with the CSF and

2:12

have pure CSF signal, which this does not.

2:15

It doesn't really have CSF signal anywhere.

2:17

Even the cystic component doesn't match the regular

2:20

old CSF. It's just not dark enough.

2:23

And then it has this nodular component.

2:25

Another common cause of intrasellar cystic mass

2:28

would be secondary empty sella from idiopathic

2:31

intracranial hypertension IIH or pseudotumor cerebri.

2:35

Then you get into obstructive hydrocephalus,

2:37

where the third ventricle can actually prolapse

2:40

down and widen the pituitary fossa.

2:44

And I've seen that happen many times,

2:46

especially in aqueductal stenosis.

2:48

Then you get into something called

2:50

a Rathke's cleft cyst,

2:51

which we'll discuss an intrasellar craniopharyngioma,

2:55

and those can calcify. So if you have calcification,

2:58

you never have calcification.

3:00

Patient with a Rathke's cyst.

3:01

So that could help you differentiate those.

3:03

You could have an arachnoid cyst that

3:05

pushes down and when they do,

3:07

they may produce a lobulated appearance

3:09

in the sellar region like this.

3:11

But then they also have little fingers that

3:13

go back this way and then up this way.

3:15

Kind of simulating a third ventricle, if you will,

3:18

an epidermoid which will have a more

3:21

serpiginous character to it.

3:23

Almost never intrasellar in origin,

3:26

rarely things like neurocytoma.

3:29

You've got to think about pituitary apoplexy.

3:31

Of course, the history is going to help you there.

3:33

You're going to have blood, which you don't have here.

3:36

And then finally a sacular thrombosed aneurysm,

3:39

which is rarely in the midline,

3:41

almost always going to be off to the side and

3:43

have some flow mismatching. So of those,

3:46

which one do you like?

3:48

Well, I am kind of going to go with the Rathke's

3:52

cyst for a couple of reasons.

3:54

One is this is a classic so-called

3:57

Chippendale or claw sign.

3:59

That appearance of pushing the enhancing

4:03

stalk and the adenohypophysis,

4:06

but also the presence of a non-enhancing

4:09

mural nodule is also seen with that.

4:12

Not all the time. Now,

4:14

these Rathke's cleft cysts can have a lot of different

4:19

appearances because of the consistency of what's

4:21

in it. They can be very proteinaceous,

4:24

so-called machine oil or cystic.

4:26

So this will be kind of a cystic one mural nodule,

4:29

but the pattern of mass effect.

4:31

Pretty classic, I would say.

4:32

Yeah, and I think one of the first things you want

4:34

to do when you have a situation like this,

4:36

besides the key point that you mentioned,

4:39

where in the sella is it? It's not in the pars distalis?

4:42

And you don't really get tumors of the pars nervosa or

4:45

of the pituitary bright spot, so that would be weird.

4:48

So it almost has to come from the pars intermedia.

4:50

So the key question is if you have a cystic mass

4:53

with a mural nodule or not, where is it arising from?

4:56

Is it arising from within the sella or did it

4:59

come from the suprasellar region and go down?

5:02

And we gave you a pretty good differential

5:04

diagnosis for the latter scenario.

5:07

Now, one other point that you already alluded to,

5:10

some people break these Rathke's cysts or pars

5:14

intermediate cysts down into two types.

5:16

The machine oil type, which can be high on T1 and bright

5:19

on T2 or variable on T2,

5:22

and then the cystic type where they look

5:23

like just kind of almost simple cysts,

5:26

but not quite matching that of cerebrospinal fluid.

5:30

Any other comments on this before we move

5:32

on to the next case?

5:33

Great case.

5:33

It's one of the best claw signs you'll ever see,

5:36

the claw. Let's move on, shall we?