0:00

You know, Dr. Shupack,

0:01

the neurohypothesis makes up only about one quarter of

0:04

the pituitary mechanism, and it's got three parts,

0:08

as we've talked about before.

0:10

It's got a stalk, it's got a pars nervosa,

0:15

also known as the posterior lobe,

0:17

and it also has a median eminence,

0:20

which is the very tip or base of the stalk,

0:23

the most proximal portion of the stalk,

0:25

which lies below the tuber cinereum.

0:27

So, in this case,

0:28

we've got kind of a weird thing going on.

0:30

We don't have our normal pituitary bright spot,

0:32

which we said before,

0:34

can be absent at a moment in time in 20% of

0:37

the population, but when it's not there,

0:40

you've got to be concerned about a few things.

0:42

So,

0:42

what's going on here in the sagittal T1-weighted image? Right. So, as Dr.

0:44

Pomerance mentioned,

0:47

we're kind of expecting a bright spot here,

0:48

but what happens if it's gone?

0:51

So, if you didn't believe in the neurohypothesis,

0:54

you will in this case, because it's not gone.

0:56

It's just kind of taking a little trip there,

0:59

going up to the east coast.

1:02

Right. So, here's your mammillary body.

1:04

So, this is an ectopic neurohypothesis,

1:06

and it's usually developmental.

1:10

I think most of the cases described as developmental

1:13

but can be associated with head trauma.

1:16

And if you get a history that says that sella

1:19

and the history is diabetes insipidus,

1:23

this could be a really important finding because,

1:26

remember,

1:28

antidiuretic hormone is part of this

1:28

function of this neurohypothesis.

1:31

So they could have abnormalities of serum

1:33

sodium that's correct. Serum sodium.

1:39

And also even up for pituitary surgery.

1:42

I haven't seen this. Exactly.

1:44

But you can have damage.

1:46

DI is another complication of pituitary surgery.

1:49

So if you see that diabetes insipidus, do they have in

1:53

surgery? What's going on with the neurohypothesis?

1:55

Things that come to mind now,

1:57

there are some associations with this.

1:59

There's a differential. Okay,

2:01

so dermoid could be one thing, a lipoma,

2:05

so it's bright on the T1.

2:07

So things that are bright on T1, you can think of.

2:09

And there are some other things that you should

2:11

look for, such as septooptic dysplasia,

2:14

Kallmann syndrome that can be associated with

2:16

this anomaly. Okay, so when you see this,

2:19

it's kind of a gee-whiz thing,

2:20

but there are some other wheels that should be turning,

2:23

looking for associations and providing a little bit of

2:26

a differential and looking at the clinical setting.

2:29

DI? No DI.

2:31

That's what your clinician is wondering.

2:33

Sure. That's probably the most important thing.

2:35

And we both know that trauma can dislodge this.

2:38

And if somebody has it dislodged with trauma,

2:40

you have to look to see if the stalk is transected.

2:44

You mentioned septo-optic dysplasia.

2:46

Pretty self-explanatory.

2:47

Kallmann syndrome would be hypogonadism with disruption

2:51

of the olfactory apparatus. It's a developmental.

2:55

And one other lesion in the differential diagnosis

2:59

would be small suprasellar cranial,

3:01

but it's too far posterior.

3:03

You're usually right above the pituitary gland or stalk.

3:07

So this is an ectopic position of the

3:09

posterior pituitary gland,

3:11

the pars nervosa component of the posterior apparatus

3:15

seen in a supra and retrocellar position.

3:17

Shall we move on? Yeah.