Interactive Transcript
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So what are we to do with this abnormality?
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We're at the T9 level in a 42-year-old male,
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and we see on this sagittal reconstruction of
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the axial scan, a calcification which
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appears to be within the thecal sac.
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So rarely, you can get disc herniations,
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which will calcify and occasionally
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perforate the thecal sac.
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But that would be two unusual things.
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You have a calcified disc and you have one
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that's perforating the thecal sac and then
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presenting as if it was an intradural extramedullary lesion.
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Doesn't make a lot of sense. When we look
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at this lesion, it's kind of cute,
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but it does look like there is a dural
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tale of calcification, if you will.
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So you'll note that there is this little
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hyperdense area which is emanating from the
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lesion and going superiorly along the dura.
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This might be the clue that this is indeed
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an intradural extramedullary calcified
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meningioma of the thoracic spine.
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Most meningiomas of the thoracic spine
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occur along the posterior dura,
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not the anterior dura.
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The other clue that this is not a disc
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herniation is that on the axial scans, we don't
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really see it attaching to the disc.
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We seem to have intervening disc between the
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lesion and therefore it's not an extradural
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disc herniation. It's really an intradural mass,
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a meningioma. Let's look on MRI.
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So this is a different patient with a more
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characteristic appearance of a meningioma.
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T1-weighted scan.
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Let's just review the anatomy real quickly.
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We have the vertebral body, we have the disc.
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We have the CSF space anterior to the spinal
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cord. We have the spinal cord.
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We have the CSF space posterior to the
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spinal cord. We have epidural fat.
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An epidural fat may be very thickened in
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patients who have epidural lipomatosis.
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Then we come into the spinous processes back
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here. And between the spinous processes,
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you have some fat as well.
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Let's look at the lesion.
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The lesion is in the thecal sac.
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There is a meniscus sign which is better seen
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on the T2-weighted scan where the
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CSF space is, if anything,
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widened at the level of the tumor
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as opposed to being narrowed.
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And it's clearly along the posterior dura.
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Not only that,
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but we have some accentuation of
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the dark signal of the dura,
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suggesting that it is thickened
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and possibly even calcified.
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This would identify the lesion as most
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likely representing a meningioma.
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The spinal cord is displaced anteriorly.
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It's important for us to make a comment about
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the spinal cord signal intensity.
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If we think that the spinal cord
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signal intensity is bright,
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it may correlate with clinical symptoms
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of a myelopathy. It may encourage
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the neurosurgeons to remove this
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tumor more readily and more quickly,
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as opposed to waiting for the lesion
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to demonstrate interval growth.
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So even when you have an intradural
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extramedullary lesion,
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you do want to make a comment as to whether
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or not it is leading to cord edema,
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which might precipitate a more aggressive
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stance by the neurosurgeons
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to remove the lesion.
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