oral surgery
Nasopalatine Duct Cyst Jamie Larmie, B.S.; Louis Mandel, D.D.S.
ABSTRACT The nasopalatine duct cyst (NPC) develops in the incisive canal from embryologic remnants of the nasopalatine duct. Clinically, the NPC’s presence is usually confined within the limits of the incisive canal but, occasionally, it may extend posteriorly to involve significant portions of the anterior hard palate. The nasopalatine duct cyst (NPC), first described by Meyer in 1914,[1,2] has been defined by the World Health Organization (WHO) as a developmental, epithelial, non-odontogenic cyst.[3] During the fetal period, an epithelial duct, the nasopalatine duct (NPD), exists as a communicator between the nasal and oral cavities. The duct probably served an olfactory function in primitive life.[4,5] Although present in the fetus, it is mostly obliterated by birth. Remnants of the duct may persist[5-8] and proliferate to form the NPC. The stimulus for the proliferation is believed to be trauma or infection, or it may even develop spontaneously. [2,7,9,10] Surprisingly, patency of the NPD may occasionally exist in adults, and its orifice is usually seen as small bilateral openings on either side of the papilla palatina.[5] The distinctive heart-shaped radiographic configuration of the NPC is best understood through an appreciation of the anatomy of the incisive canal. At the anterior aspect of the floor of the nasal cavity, on either side of the nasal septum, and in close relation to the septum, the foramina of Stensen are located. Stensen foramina open into the right and left incisive canals. These two canals course downward toward the oral cavity and join together to form the common incisive canal (Figures 1,2).
32 AUGUST/SEPTEMBER 2021 The New York State Dental Journal ●
The common canal then exits on the anterior hard palate just lingual to the maxillary central incisors at the incisive foramen beneath the papilla palatina. Consequently, a funnel-shaped Y anatomy is created. The nasal-to-oral length of the canal is reported to be 10 mm.[4,11] Although there are variations, the right and left incisive canals usually join together in the middle third of the incisive canal’s length as it slants downward and forward from the nasal cavity into the oral cavity.[11] Anatomically, the nasopalatine canal transports the terminal branches of the nasopalatine nerve and sphenopalatine artery. These structures serve to supply sensory innervation and vascularity to the tissues of the anterior hard palate. Although the NPC can occur in the young, it is seen most frequently in the 30- to 60-year age category,[1,8,10,12] with males slightly more susceptible than females.[2,8,10] Usually, the NPC is radiographically visualized as a heart-shaped radiolucency occupying the incisive foramen area (Figure 3). Its unique pattern results from the cyst’s growth conforming to the configuration of the Y anatomy of the incisive canal, plus the resistance offered superiorly by the anterior nasal spine. Inferiorly, the NPC has a tapered contour, because lateral expansion is frustrated by the roots of the central incisors. The normal radiographic width of the incisive foramen has been reported to be 6 mm.[4,8,11,13] Lucencies > 6 mm should be viewed with suspicion. Pathologic involvement by an NPC is assumed if the width exceeds 10 mm.[11] If radiologic differentiation of a normal
From the Division of Oral and Maxillofacial Surgery, Columbia University College of Dental Medicine, New York, NY.
