Synovial sarcomas of the head and neck.

Springing from mesenchyme rather than mature synovial tissues, synovial sarcomas are high-grade neoplasms that express epithelial as well as supporting tissue features. Accordingly, their histologic phenotypes can be epithelial, stromal, or mixed. Between 3% and 10% of all synovial sarcomas originate in the head and neck, particularly from parapharyngeal sites. These is no appreciable difference in biologic activity between synovial sarcomas of the head and neck and those arising from other anatomic sites. Five-year survivals are misleadingly optimistic and do not adequately reflect the natural history of the sarcoma. Synovial sarcoma is known to metastasize late, and few patients survive that event.