Abstract
Aplasia of the maxillary sinus and hypoplasia are rare conditions that can trigger symptoms such as headaches and altered speech. Most patients are asymptomatic, but given the role of these symptoms in the differential diagnoses for neoplasms and infection, such symptoms warrant investigating. We present a rare case of a young man with hypoplasia of the maxillary sinus on the left side with a large periapical cyst on the right side, diagnosed via a routine cone-beam computed tomography (CBCT). This case discusses the role of CBCT in investigating aplasia of the maxillary sinus.