Orbital schwannoma of abducens nerve: a case report and literature review

Intraorbital schwannoma arising from abducens nerve is an extremely rare entity, with only six previous case reports identified in the literature. We describe a case of intraorbital abducens nerve schwannoma in a 54-year old male, who presented with proptosis of the right eye and diplopia. Computed tomography (CT) scan and magnetic resonance imaging (MRI) showed an intraconal well-defined mass in the right orbital apex. The tumor was totally excised with the nerve intact, and the outcome was favorable. The relevant literature regarding intraorbital abducens nerve schwannoma was reviewed, and the clinical manifestations, radiological characteristics, surgical strategies, histopathological findings, and prognosis are discussed. A surgical approach should be elaborately designed for the functional preservation of the abducens nerve, in which MRI is a preferred method for providing valuable guidance. Furthermore, a strong understanding of the complicated anatomical structures surrounding the abducens nerve and lateral rectus is crucial for the complete resection of the tumor and nerve preservation.