Sinonasal schwannoma--a clinicopathological analysis of five rare cases.

Schwannoma of the nasal cavity or the sinuses is a rare condition. We report a small series of five consecutive patients; three males and two females, age range 22-81 years, all Caucasian. Symptoms were typically non-specific, and the tumours were often quite large when diagnosed, being locally infiltrating and even destructive. Histologically, the tumours were remarkable by sparse occurrence of Antoni type B areas and lack of encapsulation. Four cases were benign; however, one case of melanotic schwannoma, exhibited malignant transformation. Two of the patients had intracranial involvement, but with an intact dura. All tumours were treated surgically; only the malignant case received adjuvant radiotherapy. Patients were followed from five months to 15 years, with a median of 57 months. The benign cases have so far shown good prognosis without recurrences; however, in the case of the melanotic schwannoma a fatal malignant transformation was seen 13 years after initial diagnosis. On the basis of our review early detection and complete surgical removal is recommended.