Synovial Sarcoma of the Maxillary Sinus Arising from Fibrous Dysplasia: A Case Report

We report on a 70-year-old female who developed synovial sarcoma of the maxilla in the setting of long-standing fibrous dysplasia of the facial skeleton. Synovial sarcoma represents approximately 10% of all soft tissue sarcomas, and most commonly occurs in the limbs of young adults. In 5 to 10% of patients, the tumor arises in the head or neck. The most common site is in the hypopharynx, but it has been described in the paranasal sinuses. There have been only two previously reported cases of synovial sarcoma arising in the maxillary sinus. Fibrous dysplasia has been shown to have the potential to transform into malignant neoplasms, although there is only one reported case of the development of synovial sarcoma after diagnosis of fibrous dysplasia, which occurred in the tibia. Our patient was initially treated with chemotherapy, which failed to control the disease. She subsequently underwent a total maxillectomy and orbital exenteration with complete resection of the tumor. Microvascular free tissue transfer was used for reconstruction, and she is undergoing postoperative radiation therapy. We discuss the manifestation of fibrous dysplasia and synovial sarcoma in the skull base, and review their diagnosis and treatment.