Solitary fibrous tumor of the parapharyngeal space.

Solitary fibrous tumors are benign neoplasms of mesenchymal origin. They usually arise from the visceral or parietal pleura and peritoneum, although they have been found in many areas throughout the body. We report a case of solitary fibrous tumor of the parapharyngeal space. Microscopically, the tumor contained spindle cells with areas of marked hypercellularity without a definitepattern. Consistent with a benign lesion, there were few mitoses and no necrosis. The tumor cells stained strongly positive for CD34 and vimentin. At the 2-year follow-up, the patient was well and free of local and/or distant disease.