Low-Grade Nasopharyngeal Papillary Adenocarcinoma.

Low-grade nasopharyngeal papillary adenocarcinoma is a rare tumor, and only a limited number of cases are reported in the literature. The case reported in this study had long-term nasal catarrh with a runny nose and was admitted to the hospital. Computed tomography (CT) examination revealed polypoid mass in the nasopharynx. Pathological examination revealed typical papillary growth pattern of glandular epithelial cells. Immunohistochemical (IHC) staining showed the tumor cells to be diffusely positive for cytokeratin 7 (CK7), vimentin, and thyroid transcription factor 1 (TTF-1). The Ki-67 proliferation index was approximately 1%. In situ hybridization for latent Ebstein-virus (EBV) injection was negative. The patient did not exhibit recurrence or metastasis of the tumor.