Optic Nerve Sheath Meningioma

This is a case of an optic nerve sheath meningioma (ONSM) in a 56-year-old woman who presented with gradual, painless vision loss in her left eye. Optic disc photos at presentation showed temporal pallor of the left optic nerve (Figure 1) and Cirrus optical coherence tomography (OCT) of the retinal nerve fiber layer (RNFL) demonstrated thinning in the left eye (Figure 2). Humphrey visual fields (24-2 SITA-Fast) showed generalized depression in the left eye (Figure 3). MRI of the orbits (T1 with fat suppression, post-contrast) showed an enhancing mass along the posterior part of the left optic nerve sheath highly suggestive of an optic nerve sheath meningioma, the optic nerve itself appeared normal (Figure 4). She was treated with fractionated radiation therapy and her visual function improved (Figure 5). Optic disc photos 4 years after treatment showed temporal pallor in the left eye (Figure 6). OCT of the RNFL and GCL showed thinning in the left eye (Figure 7). OCT angiography was available for review and showed a reduction in the superficial vascular plexus in the left eye corresponding to the area of RNFL thinning (Figure 8). Follow-up MRI of the orbits (T1 with fat suppression, post-contrast), showed a small reduction in size of the left ONSM (Figure 9). [[Number of Figures and legend for each: 9 figures included. Figure 1. Optic disc photos at presentation showed temporal pallor of the left optic nerve. Figure 2. Optical coherence tomography (OCT) of the retinal nerve fiber layer (RNFL) demonstrated thinning in the left eye. Figure 3. Humphrey visual fields (24-2 SITA-Fast) showed generalized depression in the left eye. Figure 4. MRI of the orbits (T1 with fat suppression, post-contrast) showed an enhancing mass along the posterior part of the optic nerve highly suggestive of an optic nerve sheath meningioma, the optic nerve itself appeared normal. Figure 5. Humphrey visual fields (24-2 SITA-Fast) showed improved visual function after fractionated radiation therapy. Figure 6. Optic disc photos 4 years after treatment showed temporal pallor in the left eye. Figure 7. OCT of the RNFL and GCL showed thinning in the left eye. Figure 8. OCT angiography was available for review and showed a reduction in the superficial vascular plexus in the left eye corresponding to the area of RNFL thinning. Figure 9. Follow-up MRI of the orbits (T1 with fat suppression, post-contrast), showed a small reduction in size of the left ONSM.]]