Successful reconstruction using a buccal fat pad flap in misdiagnosed buccinators intramuscular synovial sarcoma: A case report

INTRODUCTION: Synovial sarcoma (SS) is a subtype of soft tissue sarcoma that primarily usually occurs in the lower extremities but rarely arises in the head and neck areas, including the oral cavity. Due to its variable presentation and similarity to benign masses in terms of age at onset, growth rate, and favorable outcomes, SS is often misdiagnosed as a benign tumor. However, it is a malignant tumor. PATIENT CONCERNS: We report the case of intramuscular SS in the oral cavity. Initially, the lesion was clinically suspected as a benign mass but was ultimately confirmed as malignant SS. DIAGNOSIS: Although histopathological examination is the first step in diagnosing SS, molecular testing to confirm the presence of SYT-SSX fusion can provide a definitive diagnosis when the histopathology is inconclusive. In this patient as well, the postoperative pathological report confirmed the diagnosis of biphasic SS, and molecular testing revealed positive SYT/SSX fusion. THERAPEUTICS INTERVENTIONS: Following the recommendation of multidisciplinary care system, a wide excision was performed including the buccinators muscle, and reconstruction was performed using a buccal fat pad flap to prevent cheek depression. OUTCOMES: On the final pathologic report, SS was removed margin-free, and there were no metastatic lymph nodes. No evidence of cheek dimpling was observed, and follow-up neck CT showed no significant changes in the lymph nodes. As a result of observation up to several months after surgery, there were no functional and aesthetic complications. CONCLUSIONS: We report a successful case of intramuscular SS resection, initially misdiagnosed as a benign mass, using a buccal fat pad flap. We also highlight the importance of correctly diagnosing SS, especially in the craniofacial region where it can be mistaken for benign masses.