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This is a 14-year-old child

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with neurofibromatosis type 1.

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Seeing an axial T2-weighted image,

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we can see this ovoid hyperintense area.

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And centered in the region of

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the left globus pallidus,

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we can see two patchy areas of signal

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abnormality in the right globus pallidus.

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If we look in this post-contrast

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T1-weighted image, we see this

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subtle halo of hyperintense

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signal around these areas.

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But before we refer to these as

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being areas of enhancement,

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we have to look at the pre-contrast T1.

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There is a hyperintense rim on

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pre-contrast T1-weighted imaging.

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So, there is no enhancement associated

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with these areas.

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They just happen to be hyperintense.

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So, looking at all the sequences is important.

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Now, if we look at this axial image on T2,

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we can see the two mammillary bodies.

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There's the optic chiasm.

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Here's the left optic tract.

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Here's the right optic tract.

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Now, the right optic tract looks asymmetrically thicker.

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Now, subtle asymmetry can possibly be related

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to obliquity slice selection.

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But even independent of the asymmetry,

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this is too thick for the right optic tract.

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If we look at this in the coronal image,

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we look at the prechiasmatic segment

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of the optic nerves,

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and there's actually asymmetric thickening

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of the prechiasmatic segment of the left

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optic nerve going into the left

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aspect of the optic chiasm.

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Now, if we go posterior,

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we can actually see there's asymmetric

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thickening and enlargement

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of the right optic tract.

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The left optic tract at this location

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looks approximately normal.

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The right optic tract is thicker,

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it's indistinct,

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and we're not seeing it clearly.

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So, this is a right optic tract glioma in the

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setting of neurofibromatosis type one,

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and likely also involvement of the left

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aspect of the optic chiasm and also

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the prechiasmatic segment of the left optic nerve.

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Now, if we go anterior to the orbits,

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seeing a little bit of tortuosity,

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we're not seeing any discrete enlargement.

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Now in this image here,

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we're seeing asymmetric hyperintense signal

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in the right optic nerve in the midorbital

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segment without significant enlargement,

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without definite abnormal enhancement.

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Given the other multifocal areas,

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this area here has to be suspicious for

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additional involvement of

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an optic pathway glioma.

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So, this shows that the optic pathway gliomas

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in neurofibromatosis type 1can manifest

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in several different locations.

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The question then becomes if there is a

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normal appearing intervening segment

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of the optic nerve on imaging,

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is that segment uninvolved

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or just subclinically involved?

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And the answer is,

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we don't know. It could be either.

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It is possible that the different areas of

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involvement are multicentric involvement,

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I say multi-centric because it may arise in

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two different locations due to

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the genetic predisposition,

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or it could be longitudinal spread of

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the glioma along the optic pathway,

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but with more focal areas that are

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discontinuous of more fusiform enlargement

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and enhancement. It could be both.

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So, that's one reason why we just need to try

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and look at the entire optic pathway,

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describe it the best we can,

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and if there's any questions,

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review it with the clinical team,

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with the oncologists,

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or anyone else who may have questions about this.