Supplementary Material for: 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 five-year survival rates. In this study, we report a case in which pterygoid muscle necrosis occurred six 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) six 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.