Clinicopathological features of SMARCA4-deficient sinonasal carcinoma

CHEN Jieyu; ZHENG Yinhai; ZHU Ying; YE Weibiao; XU Yongqiang

doi:10.3969/j.issn.1007-8096.2025.10.015

Abstract：Objective To investigate the clinicopathological characteristics,diagnosis and differential diagnosis of SMARCA4-deficient sinonasal carcinoma(SdSNC).Methods The clinicopathological data of one middle-aged male patient diagnosed with SdSNC were retrospectively analyzed.The histological morphology,immunophenotypic characteristics,and molecular genetic features of this tumor were observed.Relevant literature was reviewed.Results The patient was admitted to our hospital due to recurrent blood-tinged nasal discharge from the right nostril for more than half a year.Fiberoptic nasopharyngoscopy revealed a nasal neoplasm,and a tumor biopsy was performed.Histological examination of the biopsy specimen showed that tumor cells were arranged in nests or sheets,with pseudorosette structures formed around blood vessels in local areas.The tumor cells had scanty cytoplasm,round or oval nuclei,coarse granular chromatin,and some showed basophilic nucleoli,while mitotic figures were easily observable.The tumor stroma was mainly loose fibrous tissue with abundant blood vessels.Immunohistochemically,the tumor cells were positive for pan-cytokeratin,lacked SMARCA4 expression,and retained SMARCB1 expression.Fluorescence in situ hybridization(FISH)detection revealed breakage and deletion of the SMARCA4 gene in the tumor tissue.Conclusion SMARCA4-deficient sinonasal carcinoma is a newly recognized subtype of sinonasal undifferentiated carcinoma.This tumor is extremely rare and easily misdiagnosed in clinical imaging and pathology.Recognizing its histopathological morphology,immunophenotype,and molecular characteristics is helpful for its diagnosis and differential.