Orofacial synovial sarcoma: a clinicopathologic study of 11 new cases and review of the literature.

Synovial sarcoma arises most commonly in the lower extremity, particularly in the region of the lower thigh and knee. Yet the occurrence of thus mesenchymal neoplasm in the head and neck area has been convincingly documented, albeit confined almost exclusively to cervical and parapharyngeal sites. Therefore, in view of its rarity in the head and neck, we analyzed a group of 11 synovial sarcomas arising in the orofacial region. The series comprised nine men (82%) and two women (18%). In common with synovial sarcoma at more conventional sites, this is a disease of young adults: ages ranged from 16-49 years (median, 34 years). Topographically, two subsets were delineated, a more common facial group with eight cases (four cheek, two parotid region, one infraorbital, one submental), all arising as gradually enlarging, usually nontender, solitary tumors; and three intraoral ones (two tonsillar, one lingual), two of which were polypoid and one was an exophytic tonsillar mass which presented with hemoptysis and stridor. Follow-up data, obtained for nine patients (range, 1.3-15.0 years), disclosed three (33%) tumor-related deaths, all belonging to the facial group. Treatment, difficult to significantly correlate with survival in this small series, varied from surgical excision alone to a multimodality approach including both irradiation and chemotherapy. Histologically, all the neoplasms revealed characteristic biphasic features, predominantly fibrosarcomatous in one, but, more typically, showing epithelial clefts and/or pseudoacinar spaces in the others. Differential diagnosis, depending on the proportion of the biphasic components, ranged from spindle cell mesenchymal neoplasms to various adenocarcinomas, including those arising in mixed tumors of salivary gland.