Nasopalatine duct cyst: an analysis of 334 cases. The nasopalatine duct cyst (NPDC) is the most common cyst of nonodontogenic origin in the maxilla. However, the information reported about this lesion consists primarily of small surveys and isolated case reports. The purpose of this retrospective investigation was to gather demographic, clinical, and histologic data on a large series of NPDCs, and to compare the findings with those of previous studies. In this study, the overall mean age at diagnosis was 42.5 years, and there was a slight male predilection. The mean radiographic diameter was 17.1 mm, but 75% of the lesions were 20 mm or less in diameter. Symptoms were present in at least 70% of the cases. Only 28% of the specimens contained respiratory epithelium. There was no correlation between radiographic size, patient's age, presenting symptoms, or type of epithelium. Recurrence was noted in only 2% of the cases. 