Clinicopathologic Characteristics of Thyroid-like Low-grade Nasopharyngeal Papillary Adenocarcinoma: A Case Report

Abstract

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare neoplasm. It morphologically resembles papillary thyroid carcinoma and is immunochemically positive for thyroid transcription factor 1. Herein, we reported a case of TL-LGNPPA in a female patient of 35 years old. She felt pharyngeal foreign body sensation of unknown cause and subsequently developed dyspnea after activities. Nasopharyngeal plain computerized tomography showed no abnormalities, but laryngoscopy showed a peanut-sized smooth neoplasm with a pedicel at the posterior edge of the nasal septum. The mass was completely resected by nasopharyngoscopy. Histologic examination showed the tumor was composed of papillary configuration and tubular glands; each papilla was covered with cuboidal or columnar epithelial cells; tubular architecture and spindle cell component were also observed; some tumor cells had psammoma bodies. Immunohistochemically, tumor cells were positive for CKpan, CK7, CK19, VIM, and thyroid transcription factor 1, but negative for thyroglobulin, CK20, S-100, P63, P40, smooth muscle actin, CDX-2, and glial fibrillary acidic protein. This patient was diagnosed with TL-LGNPPA and followed up for 16 months, and metastasis and recurrence were not observed.

Thyroid-like low-grade papillary adenocarcinoma of nasopharynx

“…The most common IHC pattern of TL-LGNPPA tumour cells is TTF-1 positivity and TG negativity, which is negative for TTF-1 and diffusely positive for TG in PTC. Such finding has been reported in all previously reported cases of TL-LGNPPA as well as our patient 2–9. These two neoplasms have some similar IHC patterns including CK7 expression and vimentin 2.…”

“…In addition, BRAF V600E mutation which is commonly positive in PTC and negative in TL-LGNPPA may be used to differentiate these two tumours 5. This mutation was not seen in the case reported by Li et al 7. In Oide et al case of TL-LGNPPA, BRAF and RAS mutation was negative which shows different carcinogenesis processes of TL-LGNPPA and PTC 4…”

“…Thyroid-like LNPPA is an extremely rare tumour of nasopharynx with only a limited number of cases reported in the literature 2–9. NPPA includes 0.38%–0.48% of all malignant nasopharyngeal neoplasms 10.…”

Clinicopathological Features of Thyroid-Like Low-Grade Nasopharyngeal Papillary Adenocarcinoma: A Case Report and Review of the Literature

“…In 2005, Carrizo and Luna first reported that two pediatric patients with LGNPPA showed the expression of thyroid transcription factor-1 (TTF-1) in their tumor cell nuclei and named LGNPPA with the expression of TTF-1 "thyroid-like low-grade nasopharyngeal papillary adenocarcinoma" (TL-LGNPPA) (5). TL-LGNPPA is an extremely rare tumor; to date, only 27 cases have been reported (6).…”

Thyroid-Like Low-Grade Nasopharyngeal Papillary Adenocarcinoma

“…Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma is a rare entity; to date, only 27 cases have been reported [1]. This tumor is most frequently found in patients in the 4th decade of life and does not appear to have a sex predilection [2].…”