A case of thyroid-like low-grade nasopharyngeal papillary adenocarcinoma of the posterior nasal septum

Abstract

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare neoplasm that generally originates in the nasopharynx or the posterior nasal septum and is characterized by morphological analogy to papillary thyroid carcinoma and expression of thyroid transcription factor-1 (TTF-1). We herein report a case of TL-LGNPPA. A 35-year-old woman visited our hospital complaining of nasal congestion and nasal discharge. Nasopharyngoscopy revealed a tumor originating from the posterior nasal septum. Endoscopic endonasal surgery was performed. The tumor was composed of papillary or glandular proliferation of cuboidal epithelium, and focally short-spindle shaped cells proliferated in a fascicular pattern. Immunohistochemically, the tumor cells were positive for TTF-1 and negative for thyroglobulin. Therefore, the postoperative diagnosis was TL-LGNPPA. The patient has shown neither local recurrence nor distant metastasis in the 17 months after since the removal of the tumor.