Hybrid Schwannoma-Perineurioma of the Orbit

A 52-year-old woman presented with a 6-month history of progressive right proptosis associated with intermittent right retrobulbar and facial pain. MRI revealed a heterogeneously enhancing, well-circumscribed, ovoid, soft tissue mass in the intraconal space near the right orbital apex displacing the optic nerve medially. Excisional biopsy established the diagnosis of a schwannoma-perineurioma hybrid peripheral nerve sheath tumor (HPNST). This case represents only the second reported occurrence, to our knowledge, of an orbital schwannoma-perineurioma HPNST. A 52-year-old woman developed a schwannoma-perineurioma hybrid peripheral nerve sheath in the right orbital apex; to the authors' knowledge, this is only the second report of a tumor of this type occurring in the orbit.