Interactive Transcript
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This was a child that was being evaluated for visual
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field deficits and visual blurring.
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On the MRI of the brain,
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we identified that there was a mass at the foramen
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magnum that was located in an
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intradural extramedullary location. Let's look at this.
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Here we have the mass.
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We can see that it is extramedullary at the
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cervicomedullary junction at the skull base.
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And we see the so-called meniscus sign with
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enlargement of the CSF at the border with the tumor,
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which identifies it as intradural extramedullary.
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On the axial T2-weighted scan,
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we again see the masses separate from the spinal
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cord. So this is our intramedullary compartment,
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but it is within the dural
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thecal sac, so it's intradural extramedullary
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in location, identified here as the bright lesion.
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On our post-gadolinium-enhanced pulse sequences,
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we can see that the abnormality shows contrast
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enhancement. When we look further inferiorly,
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we see that this lesion extends outside the spinal
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canal. So if this is the edge of our dural thecal sac,
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we see that this lesion is extending outside and
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actually is going into the pre vertebral space from
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the neuroforamen at the C1-C2 level.
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I'd like to point out that this lesion has central
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lower signal intensity and a periphery
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of brighter signal intensity.
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And this is our so called target sign.
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If we were to do a sagittal through this,
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we would see as brighter on the periphery and darker
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in the center, the so-called target
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sign of neurofibromatosis, or
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neurofibroma as opposed to a schwannoma.
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And in point of fact,
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this patient has neurofibromatosis type 1,
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and this is what we would call
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a plexiform neurofibroma,
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which is one of the characteristic features
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of neurofibromatosis type 1.
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This patient also had additional lesions in the
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cervical spine. And we're going to move,
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move from the current study to one that's three
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years later after the patient has had resection of
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that cervicomedullary mass. So on this example,
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we can see that on a sagittal and coronal scan,
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that this patient has additional
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lesions in the brachial plexus.
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So this is clearly outside the spinal canal,
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which is here,
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but this is a mass that's associated with
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the brachial plexus on the right side.
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As you notice,
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it has somewhat of a lower signal intensity in the
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center and a periphery of brighter area on the
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T2-weighted scan, so-called target sign
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once again of neurofibroma.
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You'll notice that there's an additional
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one further superiorly here.
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So this patient has neurofibromatosis type 1.
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Let's look at the lumbar spine quickly
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for any additional neurofibromas,
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and we don't see anything of concern here on the
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coronal initial scan and then on the axial scans,
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no additional lesions.
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So it's important to inquire and to investigate the
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entire central nervous system when we're dealing
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with a patient with neurofibromatosis type 1.
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So let's go back to the original question.
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This was a child who had visual field
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problems and visual blurring.
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Remember that neurofibromatosis
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type 1 is associated with
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optic pathway gliomas.
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So if we look back at the patient's optic
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nerves on the scans through the orbits,
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we would be examining it closely for any evidence
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of optic nerve glioma. In this case,
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the patient did not have it.
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So for those of you who are trying to remember this,
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what are the seven major criteria
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of neurofibromatosis type 1?
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Again, we have to do this from memory.
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We have cafe au lait spots. That's one.
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Number two,
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axillary freckling.
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Number three,
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optic pathway glioma.
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Number four,
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a spinal dysplasia,
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sometimes with sphenoid wing dysplasia.
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We have number five,
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family member with neurofibromatosis type 1.
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Number six, plexiform neurofibroma.
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And number seven, lisch nodules,
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which are identified in the globes.
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So this was indeed a case of neurofibromatosis type 1
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with multiple neurofibromas in the intradural
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extramedullary, as well as extradural space,
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as well as in the brachial plexus.
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