We report 2 cases of high-grade sinonasal adenocarcinoma with a distinct morphological and immunohistochemical phenotype. Albeit histologically different from secretory carcinoma of the salivary glands, both tumors presented here share an ETV6::NTRK3 fusion. The highly cellular tumors were composed of solid and dense cribriform nests, often with comedo-like necroses in the center, and minor areas with papillary, microcystic, and trabecular formations without secretions, mostly located at the periphery of the lesion. The cells displayed high-grade features, with enlarged, crowded, and often vesicular nuclei with conspicuous nucleoli and brisk mitotic activity. The tumor cells were immunonegative for mammaglobin while showing immunopositivity for p40/p63, S100, SOX10, and GATA3, as well as for cytokeratins 7, 18, and 19. For the first time, we describe 2 cases of primary high-grade non-intestinal type adenocarcinomas of the nasal cavity, distinct from secretory carcinoma by morphology and immunoprofile, harboring the ETV6::NTRK3 fusion.

• Keywords
• ETV6::NTRK3, Nasal cavity, Salivary duct carcinoma, Secretory carcinoma, Sinonasal, non-intestinal-type adenocarcinoma,
• MeSH
• Adenocarcinoma * genetics   pathology   MeSH
• Oncogene Proteins, Fusion genetics   MeSH
• Immunohistochemistry MeSH
• Carcinoma * genetics   pathology   MeSH
• Humans MeSH
• Biomarkers, Tumor genetics   MeSH
• Breast Neoplasms MeSH
• Salivary Gland Neoplasms * genetics   pathology   MeSH
• ETS Translocation Variant 6 Protein MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH
• Names of Substances
• Oncogene Proteins, Fusion MeSH
• Biomarkers, Tumor MeSH
• NTRK3 protein, human MeSH Browser

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.

• Keywords
• ETV6-NTRK3 fusion protein, human, Immunohistochemistry, Mammary analogue secretory carcinoma, Nasal cavity,
• MeSH
• Anoctamin-1 biosynthesis   MeSH
• Exons genetics   MeSH
• Oncogene Proteins, Fusion genetics   MeSH
• Humans MeSH
• Membrane Proteins biosynthesis   MeSH
• Biomarkers, Tumor analysis   MeSH
• Neoplasm Proteins biosynthesis   MeSH
• Nose Neoplasms genetics   pathology   MeSH
• Nasal Cavity pathology   MeSH
• Mammary Analogue Secretory Carcinoma genetics   pathology   MeSH
• Sequence Analysis, DNA MeSH
• Aged MeSH
• High-Throughput Nucleotide Sequencing MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Aged MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH
• Names of Substances
• ANO1 protein, human MeSH Browser
• Anoctamin-1 MeSH
• CKAP4 protein, human MeSH Browser
• ETV6-NTRK3 fusion protein, human MeSH Browser
• Oncogene Proteins, Fusion MeSH
• Membrane Proteins MeSH
• Biomarkers, Tumor MeSH
• Neoplasm Proteins MeSH