Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is a rare primary adenocarcinoma of nasopharynx. of the nasopharynx is extremely rare, representing STL127705 less than 0.5% of all primary carcinomas of the nasopharynx [1C3]. According to the recent WHO classification, thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is considered a variant of nasopharyngeal papillary adenocarcinoma [3]. Patients usually present with nasal fullness, obstruction, STL127705 or epistaxis. The tumor exhibits exophytic growth with papillary fronds [3]. Immunostains have defined two subsets of low-grade nasopharyngeal papillary adenocarcinoma. The conventional type shows positivity with CK5/6, CK7, and S100. The other subtype is thyroid-like which shows strong positivity for TTF-1 and CK19. Both are CK20 and CDX2 negative. TL-LGPPA is extremely rare with only about 40 cases reported in English literature. This tumor is composed of papillary structures, and the papillae are lined with columnar or cuboidal epithelium. A bi-phasic pattern with spindle cell population has been reported in very few cases [4, 5]. 2. Case Report Our patient is a 54-year-old white male presented with dysphonia since the last three months. He was otherwise healthy. He had been smoking heavily for the last 35 years. No abnormality in thyroid function was detected. Flexible laryngoscopy showed a mass arising from the midline of the anterior nasopharynx. The patient underwent excision of the nasal mass. The mass was tan pink nodular (10 5 5?mm) and attached with the superior part of the posterior nasal septum. The entire tumor mass was excised by endoscopic surgery. Formalin-fixed, paraffin-embedded tissue samples were cut into 4?m thick sections and stained with hematoxylin and eosin. Immunostains were performed using the Ventana autostainer (Ventana Medical System Inc., USA) using a panel of antibodies to TTF-1, CK19, CK5/6, S-100, thyroglobulin, and Ki67. Appropriate tissue controls were used for each of the stains. Microscopically the tumor demonstrated a complex papillary Rabbit Polyclonal to OR4A15 growth with fibrovascular cores, lined by a single layer of columnar to s stratified columnar epithelium (Figures 1(a) and 1(c)). The cytoplasm in the neoplastic cells was scanty and eosinophilic and contained no mucin. The nuclei were elongated and hyperchromatic. No nuclear overlapping, grooving, or pseudonuclear inclusions were observed. Significant hyalinization was present in the fibrovascular cores (Figure 1(b)). The tumor also had several foci with solid aggregates of spindle cells (Figure 1(d)). Immunostains showed strong cytoplasmic positivity with CK19 (Figure 1(e)) and nuclear positivity with TTF-1 (Figure 1(f)) in both epithelial and the spindle cells. Tumor cells were negative for CK5/6, S-100, and thyroglobulin. No significant cellular atypia or mitosis was noted. Ki67 nuclear positivity was seen in less than 2% of the neoplastic cells. The immunomorphologic findings supported the diagnosis of thyroid-like low-grade papillary adenocarcinoma of nasopharynx. No local recurrence has been reported after 12 months of follow-up after excision. Open in a separate window Figure 1 Thyroid-like low-grade papillary adenocarcinoma of nasopharynx demonstrates arborizing papilla (a); papillae have hyalinized fibro vascular core and are lined by STL127705 a columnar epithelium (b, c). Solid component is made of spindle cells (d). Tumor cells are positive with CK19 (e) and TTF-1 (f). Besides the nasal mass, the reported patient was also found to have a laryngeal mass and a left cheek lesion. The laryngeal mass was subsequently biopsied and diagnosed as an invasive squamous cell carcinoma (T1bN0M0). The patient then received radiation therapy for the laryngeal mass. The cheek lesion was excised and diagnosed as a basal cell carcinoma with negative margins. 3. Discussion Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is a rare variant of primary adenocarcinoma of the nasopharynx. It has an interesting immunostain pattern. Low-grade nasopharyngeal papillary adenocarcinoma was first reported by Wenig et al. in 1988 [6]. Afterwards, Li et al. noticed the TTF-1 expression and reported two cases of thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) [7]. Since then, few cases have been reported. Literature review demonstrates this tumor typically locates in the nasopharynx arising from the roof or lateral wall of the nasopharynx, and in few cases, it has been noted to be attached with the back end of the nasal septum [6]. In all reported cases, the neoplasms have been exophytic, polypoid masses with or without stalk. The size has ranged from 0.3?cm to 4.0?cm. Because of its location, the patient usually presents with nasal obstruction and/or.