Abstract
Odontogenic keratocyst （OKC） is an odontogenic cyst that occurs most often around the mandibular third molars and tends to recur frequently. Here, we report a case of OKC that extended into the maxillary sinus in a 9-year-old boy. Computed tomography images revealed a cystic lesion that involved the second molar in the maxillary sinus. The cyst was treated with endoscopic sinus surgery with general anesthesia, by an otorhinolaryngologist. Marsupialization under the nasal meatus was performed because this procedure has relatively little influence on the maxilla and permanent teeth. OKC requires long-term follow-up to monitor for any possible cyst enlargement.
