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This is an MRI of the brain and orbits

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in an eleven-year-old child

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with neurofibromatosis type 1.

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We can see areas of myelin vacuolization

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in the globus pallidus bilaterally.

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We can see there's fusiform enlargement of

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the orbital segment of the left optic nerve.

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There's tortuosity.

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We can see there's a focal kinking in

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the anterior orbital segment

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of the left optic nerve.

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Just this redundancy and tortuosity

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and then, a relatively normal caliber

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by the time we get to the orbital

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apex and the optic canal.

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The right optic nerve looks approximately

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normal caliber.

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But there is some tortuosity

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we can see here.

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If we look at this on the coronal image,

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we can see the tortuosity of

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the right optic nerve,

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the left optic nerve,

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we can see the fusiform enlargement

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and then this tortuosity and redundancy,

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because as it gets larger,

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it has to figure out a way

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to fit into the orbit.

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We can see this post-contrast enhancement

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within this fusiform enlargement,

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also seen here on this coronal image.

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So, this is a fusiform optic pathway glioma

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in the orbital segment of the left optic nerve.

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There's additionally tortuosity of the right

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optic nerve without definite visible discrete glioma.

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Now if we zoom in,

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we can see that this glioma is actually

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pushing on the left lateral rectus muscle.

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On the right,

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we can see, between the optic nerve,

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we can see intraconal fat between the optic

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nerve sheath complex and the medial rectus,

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as well as laterally in the lateral

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intraconal space between the optic nerve

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sheath complex and the lateral rectus muscle.

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Here, there is contact with the medial rectus

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muscle and there's actually tenting

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of the lateral rectus muscle.

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It's pushing it outward.

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So, this is an example of a fusiform left

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optic pathway glioma in the setting

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of neurofibromatosis type 1.