AimTo present a case of unilateral refractory maxillary sinusitis that underlines the difficulties in differentiating between odontogenic inflammatory and malignant pathology.Method and MaterialThe case report discusses the clinical presentation, investigations and specialist consultations of a patient suffering from refractory maxillary sinusitis.ResultsThe eventual diagnosis of keratinising squamous cell carcinoma.ConclusionThis case presentation highlights both the difficulty and importance in determining the underlying cause of refractory maxillary sinusitis.