Imaging Clinic
A 72-year-old man presented with a 3-month history of a painful, nonhealing sore on his left upper gingiva. Computed tomography (CT) without contrast demonstrated a well-defined 2.1 × 1.8-cm expansile mass arising from the posterolateral wall of the left maxillary sinus, anterolateral to the base of the pterygoid plate (figure, A). Subsequent magnetic resonance imaging (MRI) showed that the mass was heterogeneously enhancing (figure, B, C, and D).



