Primary Nasopharyngeal Papillary Adenocarcinoma: Report of 2 Cases and Review of the Literature.

The primary nasopharyngeal papillary adenocarcinoma (NPPA) is extremely rare which accounts for less than 0.48% of all malignant neoplasms in the nasopharynx. The clinical features, diagnosis, and treatment of NPPA have not been well described.