Pterygoid Muscle Necrosis Caused by Radiation and Intra-Arterial Cisplatin Infusion Chemotherapy (RADPLAT): A Case Report

INTRODUCTION: Radiation and intra-arterial cisplatin infusion chemotherapy (RADPLAT) for advanced maxillary sinus cancer has accumulated evidence as a treatment with fewer complications and better 5-year survival rates. In this study, we report a case in which pterygoid muscle necrosis occurred 6 months following RADPLAT treatment for maxillary sinus cancer. CASE PRESENTATION: The 45-year-old woman had a long history of taking immunosuppressants against rheumatoid arthritis (RA) prior to treatment. Although achieving complete response (CR) to RADPLAT, the patient developed trismus (1 fingerbreadth or less) 6 months following treatment. Abscess formation and recurrence were suspected from the imaging findings; however, the biopsy with endoscopy indicated necrotic tissue. Currently, 18 months have passed without cancer recurrence. Although trismus temporarily improved with rehabilitation, the width of the mouth opening is currently a few millimeters, so the patient can only take liquid food. CONCLUSION: Pterygoid muscle necrosis should be recognized as a new major complication.