Management of the Primary Intraosseous Synovial Sarcoma of the Jaws: Be Careful of the Surgical Margin

Purpose: Synovial sarcoma (SS) is extremely rare in the jaws, and only 8 cases have been reported worldwide. The specific aims of this study were to report 15 cases of primary intraosseous SS (PISS) and analyze the histologic features and outcome-related prognostic factors. Materials and Methods: Data from patients diagnosed with PISS from 2004 to 2013 were collected in this retrospective study. Patient characteristics (primary location, histologic subtype, tumor size, and surgical margin) were defined as predictor variables. Local recurrence and tumor-related death were outcome variables. The association of tumor-related outcomes with patient characteristics was analyzed using Kaplan-Meier and Cox regression statistics. Other clinical and pathologic characteristics were summarized as a third category of variables for further analysis. Results: This study examined 15 cases (women, n = 10; men, n = 5) with a mean age at diagnosis of 35 years. There was no imbalance in the distribution of primary SS locations (maxilla, n = 7; mandible, n = 8). Six patients (40%) developed local recurrence and 4 patients (26.7%) had a tumor-related death. The 5-year local recurrence-free survival (LRFS) and overall survival rates were 57% and 69.1%, respectively. The strong statistical association of surgical margin with 5-year LRFS rate was shown by univariate (P = .01) and multivariate (hazard ratio = 7.598; P = .028) analyses. Conclusions: PISS is extremely rare in the jaw. Immunohistochemical analysis played an important role in the diagnosis of PISS. The surgical margin showed a strong association with local recurrence. Thus, ideal surgical margins should be achieved during surgery to obtain better local control. (C) 2015 American Association of Oral and Maxillofacial Surgeons