Malignant tumours of the maxillary sinus and benign conditions including fibro-osseus dysplasia, mucocele, and different odontogenic cystic lesions may present with expansile maxillary masses. Odontogenic keratocystis in the maxilla is relatively rare and invasion of the maxillary sinus unusual. We describe a patient with odontogenic keratocyst of the maxillary sinus. Differential diagnosis with expanding intrasinusal cyst can be assessed on the basis of CT findings: upward displacement of the inferior floor of the maxillary sinus is a peculiar finding in extrasinusal masses: as a consequence, the size of maxillary sinus is reduced, mimicking antral hypoplasia. The superiorly displaced maxillary sinus floor should not be misinterpreted as the calcified wall of an intrasinusal mucocele. MRI is valuable in demonstrating the relation between the odontogenic keratocyst and surrounding structures. However, as the cyst may show high signal intensity on T1-weighted scans because of its contents (epithelial debris, blood degradation products), differential diagnosis of extrasinusal masses involving the sinus and intrasinusal mucocele may be difficult.
An Unusually Large Parakeratinised Odontogenic Keratocyst in the Maxilla With Extension Into the Floor of the Maxillary Sinus
