Synovial sarcomas account for 5% of all pediatric soft tissue sarcomas, and primarily arise in the extremities. We report a case of synovial sarcoma arising in the right infra-auricular region. A 29-year-old woman presented with a 2-months’ history of a growing and slight painful tumor in the infra-auricular region. Pleomorphic adenoma arising from the lower pole of the parotid gland was suspected based on the findings of MRI and fine needle aspiration cytology of the tumor, and the tumor was resected. However, additional dissection was necessitated by the final diagnosis of synovial sarcoma by histopathological examination of the resected tumor. The SYT fusion gene from chromosomal translocation was detected by fluorescence in situ hybridization. Eight months later, a recurrent tumor was detected in the almost same region, and further dissection was performed with preservation of the mandibular branch of the facial nerve. The patient was administered postoperative radiotherapy at the dose of 60Gy, even though it was possible to resect the tumor with an adequate safety margin.
