Malignant solitary fibrous tumor of the tongue.

Solitary fibrous tumor is a generally benign spindle-cell neoplasm that has been predominantly described in the visceral pleura and other serosal sites and is extremely rare in the head and neck area. We report the first known case of malignant solitary fibrous tumor of the tongue in a 57-year-old female patient who experienced rapid growth of a longstanding right anterior tongue mass, with associated dysphagia and dysarthria. Magnetic resonance imaging was suggestive of a low-flow vascular malformation not requiring preoperative embolization. The patient underwent partial peroral glossectomy for the excision of the tumor. Final pathology, however, was consistent with solitary fibrous tumor, characterized as malignant by histopathologic criteria, and the patient was returned for re-excision of the close surgical margins. The patient has experienced symptomatic improvement, and she remains free of recurrence 12 months later. All reports of solitary fibrous tumors of the oral cavity and 3 reports of the tongue tumors described in the literature to date represent benign lesions. To our knowledge, this is the first report of a malignant solitary fibrous tumor of the tongue. Presentation, differential diagnosis, criteria for malignancy, treatment, and possible prognostic implications of this rare entity are discussed.