Inflammatory histopathogenesis of nasopalatine duct cyst: a clinicopathological study of 41 cases

The aim of this study is to characterize immunohistochemical profiles of lining epithelia of nasopalatine duct cyst (NPC) as well as to correlate those findings with their clinicopathological features to understand the histopathogenesis of NPC.

Forty-one surgical specimens from NPC were examined for clinical profiles and expression of keratin-7, 13, MUC-1, and P63 by immunohistochemistry, compared to radicular cyst (RC) and maxillary sinusitis.

Nasopalatine duct cyst was clinically characterized by male predominant occurrence: 44% of the cases involved tooth roots, and 70% with inflammatory backgrounds. Lining epithelia of NPCs without daughter cysts were immunohistochemically distinguished into three layers: a keratin 7-positive (+) ciliated cell layer in the surface, a keratin-13+ middle layer, and a MUC-1+/P63+ lower half, indicating that they were not respiratory epithelia, and the same layering pattern was observed in RC. However, those immunolocalization patterns of the main cyst lining with daughter cyst were exactly the same as those of daughter cyst linings as well as duct epithelia of mucous glands.

Two possible histopathogenesis of NPC were clarified: one was inflammatory cyst like RC and the other was salivary duct cyst-like mucocele.