Optic Nerve Sheath Schwannoma of the Orbit: A case report

• Main Author: Nyoman Golden
• Format: Article
• Language: English
• Published: DiscoverSys 2019-01-01
• Series: Bali Medical Journal
• Subjects: optic nerve sheath, schwannoma, orbit
• Online Access: https://balimedicaljournal.org/index.php/bmj/article/view/1308

<p><span>From the anatomical point of view s</span><span lang="IN">chwannoma of optic nerve is anatomically impossible, </span><span>as Schwann cells </span><span lang="IN">are absent </span><span>in the optic nerve</span><span lang="IN">. However, there were five</span><span> cases of optic </span><span lang="IN">nerve s</span><span>chwannoma had been reported. </span><span lang="IN">Among the five cases, t</span><span>hree</span><span lang="IN"> were located in the orbit.</span></p><p><span lang="IN">The authors present a case of orbital schwannoma<span>  </span>arising from the optic nerve. A 26 year old </span><span>female</span><span lang="IN"> presented with gradual decreasing of vision followed by<span>  </span>proptosis of the right eye over four years</span><span> duration</span><span lang="IN">. Three weeks before admission the patient was noted totally blind. T</span><span>he globe was straight</span><span>proptosed with ocular motility was </span><span lang="IN">restricted</span><span> to all </span><span lang="IN">direction</span><span>. The</span><span lang="IN">re was no perception of light</span><span>. </span><span lang="IN">The pupil was dilated</span><span> and fixed</span><span lang="IN">. </span><span>The cornea was clear and the sensation was present. There w</span><span lang="IN">ere</span><span> no birthmarks </span><span lang="IN">and family history </span><span>suggesting </span><span lang="IN">n</span><span>eurofibromatosis. CT scan showed an ovoid homogenous enhanced tumor that filled most of the orbit and extended into cavernous sinus through the enlarged superior orbital fissure and into anterior portion of optic canal producing an enlargement of that structure. </span><span lang="IN">On the basis of </span><span>CT scan </span><span lang="IN">findings, the preoperative diagnosis in this case included cavernous hemangioma, meningioma and optic nerve</span><span lang="IN">glioma.</span></p><p><span>Frontotemporal craniotomy with orbital osteotomy was performed. The optic canal and the superior orbital fissure were unroofed. The tumor was well encapsulated. Intratumoral decompression and piecemeal capsule resection were done. As the size of the tumor was decreased, the optic </span><span lang="IN">nerve just behind the globe </span><span>was indentified and the medial side of this nerve </span><span lang="IN">fused with the mass.<span>  </span></span><span>Posteriorly optic nerve could not be identified due to it was engulfed by tumor itself</span><span lang="IN">. </span><span>Extension of some tumors into superior orbital fissure and cavernous sinus limited their surgical resection. </span><span lang="IN">Postoperatively</span><span>,</span><span lang="IN"> t</span><span>he patient experienced</span><span lang="IN"> temporary</span><span> ptosis</span><span lang="IN"> and op</span><span>h</span><span lang="IN">thalmop</span><span>legia</span><span lang="IN">. The pathological report was optic nerve schwannoma<span>  </span>.</span></p><span lang="IN">This present case </span><span>is the fourth case of primary </span><span lang="IN">orbital </span><span>optic nerve schwannoma </span><span lang="IN">has ever been reported. Since this tumor originates from optic sheath, decreasing of vision would appeared first. The authors suggest to include orbital optic nerve schwannoma in the differential diagnosis of perioptic tumors although its occurence is exceedingly rare.</span>