Background: Chronic maxillary sinusitis is most often linked to dental, allergic, or anatomical etiologies, with foreign body-induced forms remaining rare. This case report describes a unique occurrence of chronic maxillary sinusitis resulting from misplaced hyaluronic filler due to a facial esthetic procedure. Case presentation: A 60-year-old woman experienced right-sided maxillary sinusitis symptoms for three years after hyaluronic filler injections. Multi-slice computed tomography showed total sinus opacification, a vermicular foreign body, and a small anterior wall perforation. The patient underwent Caldwell-Luc surgery for foreign body removal and mucosal excision, followed by histopathological analysis. Results: The procedure was successful, with complete extraction of the foreign body compatible with hyaluronic filler. Postoperative recovery was uneventful, and symptoms resolved. This rare complication likely resulted from accidental filler penetration into the maxillary sinus during the injection. Conclusions: To the best of our knowledge, after a detailed search of the available literature, this is the first reported case of chronic maxillary sinusitis caused by material that is compatible with misplaced hyaluronic filler. It stresses the critical need to minimize serious complications in the facial esthetic procedures through detailed anatomical knowledge, technical skill, and a strict credentialing protocol of practitioners. Further awareness and regulations could improve patient safety.