Keratocystic Odontogenic Tumor Associated with Impacted Molar in the Maxillary Sinus Causing Osteomyelitis.

Keratocystic odontogenic tumors are cystic masses that arise from cells involved in tooth development. These lesions can be very locally aggressive and have a remarkable rate of recurrence. This combination of traits necessitates aggressive treatment and monitoring. They most commonly affect the mandible; an uncommon presentation is to involve the maxillary sinus. Here we present a case of a keratocystic odontogenic tumor that developed in association with an impacted third molar in the maxillary sinus that subsequently became infected and evolved to maxillary osteomyelitis.