Conservative approach to recurrent calcifying cystic odontogenic tumor occupying the maxillary sinus: a case report.

Calcifying cystic odontogenic tumor (CCOT) is an uncommon benign cystic neoplasm of the jaw that develops from the odontogenic epithelium. Invasion into the maxillary sinus by a CCOT is not a typical, and the recurrence of the cystic variant of CCOT in the posterior maxilla is rare. This report describes a recurrent CCOT occupying most of the maxillary sinus of a 24-year-old male patient. As a treatment, marsupialization was carried out as a means of decompression, and the involved teeth were all endodontically treated. Afterward, surgical enucleation was performed. The size of the lesion continued to shrink after marsupialization, and the maxillary sinus restored its volume. This patient has been followed-up for 3 years after the surgery, and there have not been any signs of recurrence.