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This is a 77-year-old female who's got a visual problem.

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And there is a mass near the right orbital apex.

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We've got a T1 without contrast,

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T1 with contrast, all axial,

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and a T2 axial.

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Let's scroll up and down a little bit so that our viewing

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audience gets a feel for what we're looking at.

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Might not be a bad idea to pull up the coronal projection.

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And you can see a dural attachment,

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a flat dural attachment along the planum sphenoidale,

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and this is a more on plot growth pattern of

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meningioma involving portions of the sphenoid, but also,

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most importantly, involving the orbital apex.

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So when the orbital apex is involved, as it is here,

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you can still see it going into the back of the orbit.

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You have to be concerned about compromise of the optic nerve.

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And if you go and look inside an eye like this,

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you may actually see nerve pallor because the

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nerve is subjected to extremes of ischemia.

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On the other hand,

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if this lesion is pretty big and it grows backwards,

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and gives you obstructive hydrocephalus.

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You may have pallor due to vascular compromise on

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this side, but papilledema on the other side.

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That's weird.

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So one pale and one hot, one swollen,

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and that's known as the Foster Kennedy syndrome.

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And it's very typical of meningiomas that cross the

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midline or go back in and obstruct the third ventricle,

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yet involve the orbital apex.

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This one is involving the orbital apex.

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Now, another characteristic of meningiomas in this region,

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especially the onclock ones,

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is that they like to kind of grow and

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wrap themselves around vessels.

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And that can be very problematic because it makes them

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very difficult to get out of there and they

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can even cause vascular occlusions.

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Do you want to make any other comments about how

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meningiomas relate to the skull

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base and the onclock type?

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So I think...

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actually, everything you said

1:49

was exactly what you want to look for.

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Important things to look for are the arteries,

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what is the lesion doing to the arteries?

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Is it narrowing the arteries?

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Is it obstructing the arteries?

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And then what is it doing to the cranial nerves?

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I think in dislocation,

2:00

that is probably the most important thing to discuss.

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So, you might want to have an MRA or a dynamic

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CTA or a dynamic MRA in a case like this,

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just so you map out the vascular anatomy before you go

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tackle a lesion like this because you're trying

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to save the patient's vision on one eye.

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By the way, for those of you that are detail-oriented,

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the optic lens is hyperintense,

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and that's typically what you see when

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somebody has done a lens replacement.

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So this patient has had cataract surgery.

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So, in summary,

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this is an example of an optic nerve meningioma

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that's involving the apex.

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Now, it probably came from the sphenoid ridge

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and then went into the apex

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or the anterior clinoid and went into the apex

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as opposed to the primary optic nerve meningioma,

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in which you'll have a nerve.

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And then along the course of the nerve,

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you'll have what's known as the tram track of the meningioma.

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So you'll actually see the nerve inside.

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You may see a little cleft between the

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meningioma and the nerve itself.

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I'll draw the cleft with another color.

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Cleft maybe here in yellow.

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And then you'll have the meningioma as a more

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solid structure on the outside.

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That's gray.

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And the nerve itself will also be gray.

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So that's what gives you this railroad track

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or tram track sign.

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More typical of primary optic nerve meningioma,

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as opposed to one that has

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grown in from the back.

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Let's move on.