(Mammary Analogue) Secretory Carcinoma of the Nasal Cavity: Report of a Rare Case with p63 and DOG1 Expression and Uncommon Exon 4-Exon 14 ETV6-NTRK3 Fusion Diagnosed with Next Generation Sequencing.

We present a 72 years old male with a left nasal cavity (mammary analogue) secretory carcinoma (SC) which exhibited classical morphological features on light microscopical examination, diffuse strong S100 and mammoglobin positivity on immunohistochemistry, and ETV6-NTRK3 gene fusion on next generation sequencing (NGS) analysis. Unusual features of this tumor are expression of p63 and DOG1 on immunohistochemistry and the atypical junction between Exon 4 of the ETV6 gene and Exon 14 of the NTRK3 gene.