Malignant parapharyngeal schwannoma (neurilemmoma).

A malignant parapharyngeal neurilemmoma developed in a 45-year-old woman who had had a benign solitary neurilemmoma removed from the same area nine years previously. Incomplete excision was achieved through a mandibulotomy approach. Malignant schwannoma usually is associated with neurofibromatosis and has a poor prognosis, spreading along the nerve of origin or by blood stream. Small localized tumors should be treated aggressively by surgery. The possibility that a previously benign schwannoma underwent malignant transformation must be considered.