Minimally invasive treatment for hard palate-invading maxillary keratocystic odontogenic tumor

Keratocystic odontogenic tumor (KCOT) is one of the benign developmental odontogenic cystic lesions arising from impacted teeth. In comparison to other odontogenic cysts, such as radicular cysts and dentigerous cysts, KCOT is known to be more aggressive and is associated with a relatively high recurrence rate. Traditionally, KCOT has been treated with total resection through sublabial incision. Marsupialization is advocated to reduce surgical invasion. However in all the cases, marsupialization was performed in the oral cavity. With the recent development of appropriate instruments and the endoscopic modified medial maxillectomy (EMMM) technique, which allows preservation of the inferior turbinate and nasolacrimal duct, an exclusive endoscopic approach to KCOT becomes possible. However, when the KCOT invades the hard palate, total resection of the tumor requires subtotal maxillectomy including hard palate. Consequently, as the maxillary sinus connects to the oral cavity, life-long use of a prosthesis becomes mandatory. Here we report a case of a seventeen-year-old female with a hard palate-invading KCOT who was successfully treated with the EMMM approach. The KCOT was fenestrated to the nasal cavity, leading to preservation of the hard palate. The lesion invading the hard palate was found to remain unchanged over one year upon follow-up. The trans-nasal approach with EMMM is a direct, minimally invasive method providing a direct field of view for the treatment of maxillary odontogenic cysts. Marsupialization of the KCOT with the EMMM technique might be a viable treatment option if the maxillary KCOT invades surrounding structures.