台耳醫誌

Dentigerous cyst is the second most common type of odontogenic cyst after periapical cyst. The dental follicle of unerupted tooth is believed to be its origin, and the mandibular third molar is the most frequently involved tooth. Ectopic tooth is the erupted tooth outside the dental arch, which has reportedly been observed in the nasal septum, mandibular condyle, coronoid process, palate, and maxillary sinus. The etiology of ectopic tooth eruption is still unclear. Dentigerous cyst associated with an ectopic tooth in the maxillary sinus is somewhat rare. Symptoms related to rhinosinusitis usually appear late in the process. Surgical approaches include transoral Caldwell-Luc procedure or transnasal endoscopic surgery, and the standard treatment is the enucleation and extraction of the associated tooth. In case of large cysts, marsupialization decompression is advocated. A 41-year-old woman with the complaint of postnasal drip and hyposmia for the last 2 months presented to our ENT department. Noncontrast sinus computed tomography scan revealed an ectopic tooth located in the posterosuperior aspect of the left maxillary sinus and surrounded by an expansile cyst. This case report demonstrates a minimally invasive management by transnasal endoscopic decompression via maxillary antrostomy, followed by removal of most of the cyst lining epithelium while preserving the ectopic tooth, to prevent internal maxillary artery injury and oroantral fistula formation. The patient remained asymptomatic over a postoperative follow-up time of half-year, and no recurrence was observed on sinoscope examination.
(J Taiwan Otolaryngol Head Neck Surg 2021; 56:164-168)