Oculomotor nerve schwannoma of orbit with extension into cavernous sinus

Abstract

Schwannomas (neurilemmomas) are benign encapsulated, slow growing peripheral nerve sheath tumors. Primary orbital schwannomas are uncommon, accounting for about 1–4% of orbital tumors. Characteristically, they arise from the first division of the trigeminal nerve. Oculomotor schwannomas are rare tumors with only one case reported till date. Here, we report a 28-year-old male presenting with an axial proptosis of left eyeball with progressive loss of vision. Magnetic resonance imaging of orbit revealed a large left-sided orbital mass extending into cavernous sinus. Surgical excision of the mass was done, and based on clinical, histological, and immunohistochemical analysis, a final diagnosis of oculomotor nerve schwannoma with left orbital extension was made.