Interactive Transcript
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Dr. Shupack.
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This is a 14-year-old man who
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was playing a football game,
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American football, and had a contact
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injury and now has a headache.
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So this case really had nothing to do with the pituitary
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gland, although we saw something kind of strange.
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I just want to touch on some of the variations and
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summarize a few of those that we have discussed
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previously. We said that the pituitary gland,
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which kind of has a U shape, also has a stalk.
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The stalk can be sloped.
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Normally the stalk can deviate to either side.
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We said that the stalk is a little chubbier
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up top and it tapers as you go down low.
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That's fine. That's not a variation, that's normal.
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We also said that in the sagittal projection the back of
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the pituitary gland will have a pituitary bright spot.
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But occasionally,
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in about ten to 20% of the population at a moment
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in time, that bright spot can be missing.
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We said sometimes the top of the gland is flat or
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sometimes the top of the gland is
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a little bit convex upward.
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We also said the gland can physiologically hypertrophy
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at various stages in life, pregnancy,
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during puberty.
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And then we have an interesting variation here.
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We've got slight asymmetry in the amount of marrow in
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the left anterior clinoid compared to the right.
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But on occasion, I've had individuals with hugely aerated
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clinoids so that you have a big black spot right
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here and it can simulate an aneurysm.
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We talked about that in our pitfalls book
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that we generated many years ago.
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But this sagittal projection is kind of strange-looking.
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It's a young guy, and he's got this low signal intensity
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abnormality or pseudo abnormality within the gland.
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So what is going on?
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Right, well,
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actually, I have that pitfall book
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and I'm glad I do because
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it's going to come in handy on this one.
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So this one was something totally unrelated, and then I
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was showing it to one of my colleagues looking at the
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ventricles and stuff like that, and he said, "Well yeah,
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what about that pituitary cyst?"
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I better take another look at that one.
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But this is where the pitfalls book comes in handy.
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So we do see this abnormality here.
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But if we correlate the images, and that's one of the
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themes here, figure out where we are in the gland,
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you can see that that happens to be the medial border
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of the carotid. Okay, so what we're saying,
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and this is also in your pitfalls book, you showed it to
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me my first year here when I missed this problem that
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we're averaging the carotid. And this person,
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if we look at the coronal image,
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it's pretty narrow there. Okay,
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so there's something called kissing carotids
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where the carotids have a variation.
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They can be far apart or narrow, and in this case,
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that's about 5 mm. They're pretty narrow.
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It's pretty narrow. What should they be?
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Well, in order to do a transsphenoidal surgery,
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you need about a centimeter.
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So I hope this guy never needs that,
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because this is another thing that you need to report.
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If you're talking about a sellar or suprasellar lesion that
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the surgeon is going to be thinking about because if
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you try to go in here and there are kissing carotids,
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there's a good chance of ending up with a carotid
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injury and not getting your tumor out.
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I mean,
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I'm a little embarrassed about that because until I met
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you, I knew about the entity, I knew about the pitfall,
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but I did not know about the surgical significance
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of it. Right. So thank goodness we met.
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Right? Well, yeah,
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that's something you don't ever want
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to experience if you can avoid it.
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We talked earlier about aeration of the sphenoid.
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You have to get access to the sellar
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through an anterior approach.
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But you also have to have a sella that's wide
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enough if you actually work through,
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particularly if you have a suprasellar portion.
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Okay.
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So the size and shape of the sella and the structures
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around it are going to be sort of one of the themes of
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our case review. I want to make one other point.
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This is a great pitfall because many of you out there
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are wondering, well, the carotid has a flow void.
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It's black. Why isn't this thing black?
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And the reason is you're right in the wall of the
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carotid. You're not actually imaging the lumen.
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You're along the free wall of the carotid
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volume averaging with the adjacent pars,
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the stalks of the pituitary gland.
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Then you keep going over to the other side
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and you've got the exact same thing.
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You're along the inner free wall of the carotid,
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not in the lumen.
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If you're in the lumen, volume averaging the lumen,
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then it'll be a black spot.
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But this time it's a gray spot because it's volume
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averaging of the kissing carotid walls.
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