Objective To Summary the clinical characteristics, histological morphology, immunophenotype, diagnostic features, differential diagnosis, treatment and follow-up of SMARCB1 (INI1)?deficient sinonasal carcinoma (SDSC), and deepen the understanding of this disease. Methods The clinicopathologic data of one SDSC patient diagnosed and treated in Hospital were collected and analyzed and literatures were reviewed. Results An 59-year-old woman was diagnosed with T3 stage, the imaging of computer tomography and magnetic resonance showed a mass occupying the right nasal cavity and ethmoid sinus with bone destruction. Microscopically, the tumor cells were composed of epithelioid or basal cell-like morphology, most were consistent with mild pleomorphism, The mitotic image was easy to see, no obvious squamous or adenoid differentiation was observed, and a few residual normal mucosal epithelium could be seen around the tumor. Immunohistochemical staining showed that INI-1 nuclear expression was completely absent in tumor cells. Conclusions SDSC is a rare and new subtype of undifferentiated carcinoma of sinuses. It is highly invasive with rapid progression, relapse, early metastasis and poor prognosis. INI-1 immunohistochemical detection was performed for the poorly differentiated carcinoma of sinonasal, which was helpful for the accurate diagnosis of this subcategory. Preoperative TPF chemotherapy helps to shrink the lesion and facilitate radical surgical excision.