Molecular and clinicopathological findings in a tonsillar synovial sarcoma. A case study and review of the literature.

Synovial sarcoma (SS), 3-5% of which occurs in the head and neck region, has generally been regarded as high grade sarcoma. Recent analysis of clinical, morphological, and molecular characteristics of SS, however, identified low and high risk group of patients, resulting in important implications for the treatment of patients diagnosed with SS. We describe the case of a 31-year-old male who presented with biphasic SS with poorly differentiated areas (clinical stage IIA) in a palatine tonsil, an extremely rare site of SS. Molecular analyses revealed typical t(X;18) translocation of the SYT gene and a SYT/SSX1 fusion type. The tumor was surgically resected with free margins. Adjuvant radiotherapy or chemotherapy was not considered indicated. To date, the patient has remained free of tumor for 4 years after surgery. Literature review reveals that primary tonsillar HNSS has previously been documented only in three patients. In all of these patients the tumor was histologically biphasic; however only one published case and the case presented here showed areas of poor differentiation. We discuss the relevance of the presented findings with regard to prognostic and therapeutic considerations in SS in the head and neck region.