Malignant peripheral nerve sheath tumor of the orbit: malignant transformation from neurofibroma without neurofibromatosis.

A 52-year-old woman suffered from progressive proptosis and vision loss due to a large tumor in her right orbit. Multiple recurrences of the tumor were treated with surgical excision. The pathologic diagnosis in each recurrence was neurofibroma, and the tumor transformed to malignant peripheral nerve sheath tumor in the final pathologic diagnosis. Orbital exenteration and postoperative irradiation were applied and there has been no evidence of tumor recurrence 5 years postoperatively.